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How to treat
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Bacterial
infections
Fungal infections
Viral infections
Infestations
The author
DR GAYLE FISCHER,
senior lecturer in dermatology,
University of Sydney, and
paediatric dermatologist, Royal
North Shore Hospital,
St Leonards, NSW.
Background
ALTHOUGH the most common
reason for children to visit a dermatologist is atopic eczema, skin infections are almost as common as a
cause of skin problems in this age
group.
Although infection of the skin can
occur at any age, children present
more often with infectious skin disease than adults. Part of the reason
for this is because those with eczema
are prone to infection, but also children experience rashes in connection
with viral illnesses much more often.
cont’d page 27
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How to treat – skin infections and infestations in children
Bacterial infections
STAPHYLOCOCCUS
aureus is the most common
cause of skin infection in all
age groups, both as a primary
pathogen but also as the most
common cause of secondary
infection on an underlying
condition, particularly atopic
eczema.
Although many patients are
alarmed at the words ‘golden
staph’, S aureus most often
causes mild superficial infections, which can sometimes be
managed by topical therapy
only. Many patients have
heard of this infection in association with sepsis and hospital-acquired methicillin-resistant S aureus (MRSA). This is
unusual in children.
Nevertheless sometimes
bacterial skin infections may
be serious. In addition to less
severe infections, such as
impetigo, staphylococcal
toxins and antigens can be
responsible for serious illness
with skin signs, for example,
toxic shock, staphylococcal
scalded-skin syndrome and
staphylococcal scarlatina.
S aureus can act as a superantigen, which results in an
inflammatory cascade that
worsens dermatitis. Some
cases of osteomyelitis in children, which is also usually due
to S aureus, are thought to be
acquired via breaks in the skin.
In all longstanding cases of
S aureus infection, a carrier
state can occur that makes the
infection difficult to eradicate.
Family members may also
become carriers, re-infecting
their child without any clinical
signs themselves.
Cutaneous infections may
also be due to beta-haemolytic
streptococci, usually group A
(Streptococcus pyogenes). This
organism may also cause trivial superficial infections but is
somewhat more likely to
become invasive than S
aureus, resulting in cellulitis.
Streptococci also elaborate
toxins and, as a result, streptococcal skin infections may
be complicated by a variety of
post-infectious immune-mediated diseases such as glomerulonephritis and vasculitis.
Streptococci may also cause
scarlet fever and toxic shock.
Because of the potential dangers of streptococcal infection,
systemic antibiotics should
always be used in preference
to topical antibiotics.
Other bacteria causing skin
infection are encountered
uncommonly. The incidence
of Haemophilus influenzae
cellulitis in young children is
now much lower than it used
to be because of immunisation.
Pseudomonas aeruginosa very
occasionally causes folliculitis.
Impetigo and folliculitis
Impetigo is caused most commonly by S aureus and less
commonly by group A S pyogenes. In some lesions both
organisms are cultured. Certain racial groups, particularly
Aboriginal and South Pacific
Author’s case study — an exacerbation of
longstanding eczema
JOSH, eight, has atopic eczema. This is usually easily
controlled with moisturisers and mild-to-moderate
corticosteroid creams. However, in the last three months it has
seemed much more severe and treatment no longer seems to
be working.
On examination the usual eczema was present, but there
were also many pustules scattered on Josh’s legs and areas of
moist crusting overlying the eczema. Josh had previously had
an attack of impetigo complicating his eczema and his 10year-old sister had also had pustules from time to time.
A diagnosis of superinfected eczema with chronic folliculitis
was made and Josh was started on oral cephalexin. His usual
bath oil was changed to one containing triclosan.
A skin swab from a pustule demonstrated S aureus,
fortunately sensitive to cephalexin, as most communityacquired infections are. Nasal swabs from Josh and his sister
and mother were all positive. The whole family was treated with
mupirocin nasal ointment bd for a week and everyone used an
antiseptic wash. Hot-water washing of clothes, sheets and
towels was started.
Within a couple of weeks the infection had cleared and
Josh’s eczema became easy to treat again, but he will need
regular follow-up to make sure the carrier state does not return.
Josh has probably been colonised by S aureus for months to
years. He is prone to this because of his eczema, but his sister
had aquired the infection, with clinical folliculitis, and his
mother was an asymptomatic carrier.
Impetigo in an Indigenous child.
Bullous impetigo.
Folliculitis.
Islander peoples, are more
susceptible to S pyogenes
infections.
Impetigo presents in several
different ways. The most
common form is crusted, or
non-bullous, impetigo, seen
with itchy but not painful
yellow crusts and erosions.
Much less commonly impetigo
may cause blisters. This is
known as bullous impetigo.
The blisters can look quite
dramatic but they are not
painful. They are superficial
and erode quickly to leave a
brownish crust.
When impetigo is caused by
streptococcus, it may present
as a painful ulcer surmounted
by a thick crust. This is
known as ecthyma.
Impetigo may also supervene on atopic dermatitis.
When this happens the rash
becomes moist and crusted
and may weep. The presentation is more complex than
when impetigo presents as a
primary problem, as in addition to treating the infection
it is essential to control the
underlying problem.
Even though clinically indistinguishable from impetigo
due to sensitive organisms, in
some children impetigo is
caused by MRSA, both multiresistant and community
acquired. In the latter case,
treatment with either clindamycin or sulfamethoxazoletrimethoprim is required. In
the former, it may be necessary to use IV antibiotics,
guided by susceptibility testing, as no oral antibiotics will
be effective.
Folliculitis is a common
condition that presents with
itchy pustular lesions. In
children it is often found on
the buttocks, especially if
they are in night nappies;
however, it can occur as an
acute event or may supervene
on eczema.
Folliculitis is most often
due to S aureus infection, of
which the child is often a
chronic carrier, but other
organisms can be involved. P
aeruginosa (usually acquired
from water contaminated by
pseudomonas colonisation of
plastic bath toys or water
tanks), pitysporum and herpes
simplex virus may also cause
the condition.
Folliculitis may also be noninfective, due to maceration
and irritation of hair follicles.
Because S aureus is not the
only cause, it is helpful to take
a swab and sometimes a viral
culture and fungal scraping
for microscopy.
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Boils are deep forms of
folliculitis and are usually
painful. The causative organism is generally S aureus.
Individual lesions can be
treated by simple drainage
but patients with them are
very often S aureus carriers and
will need treatment for this.
Management
In all cases a skin swab will
confirm the diagnosis within
48 hours. Although not
always done in general practice, culture is important to
determine sensitivities and to
assess whether the impetigo is
due to streptococcus. This is
particularly important in
racial groups prone to infection with this organism, who
may go on to develop
glomerulonephritis.
When impetigo is localised,
treatment can be initiated with
topical mupirocin 2% cream
or ointment. However, when
it is widespread or severe it is
reasonable while awaiting the
results of culture to start therapy with flucloxacillin,
cephalexin or roxithromycin.
In all cases bathing with
saline or even just soap and
water to remove the crusts
reduces the burden of organisms.
When streptococcus is suspected, oral cephalexin is the
most practical treatment. The
logistics of giving oral penicillin can be somewhat daunting to parents because of the
need to take it on an empty
stomach. If you are unsure
whether staphylococcus or
streptococcus is the cause of
impetigo, cephalexin and roxithromycin usually cover both
organisms.
It is not uncommon for
impetigo to become recurrent
or resistant to treatment. In
this situation it is reasonable
to assume chronic carriage of
S aureus. This can be confirmed with a nasal and/or
perineal swab, depending on
the location of the lesions. If
swabs are positive, the whole
family and close contacts may
need treatment.
S aureus carrier states
S aureus is frequently present
on skin as a colonist. Colonisation favours hair-bearing
areas, including the anterior
nares, genital area, axilla and
scalp. Many patients who are
carriers are asymptomatic;
however, some — particularly
children with atopic dermatitis
— are prone to recurrent
staphylococcal infections,
including all those mentioned
above. They may also complain of persistent crusting of
the anterior nares.
For patients with recurrent
staphylococcal skin infections
the usual treatment is initiated
but at the same time it is helpful to document chronic carriage with nasal and/or perineal swabs and start a ‘staph
eradication program’ using
mupirocin 2% nasal ointment
intranasally, bd for seven
days, as well as washing daily
with an antiseptic wash containing triclosan 1% or
chlorhexidine 2%, paying particular attention to hair-bearing areas.
Recent studies also show
that half a cup of ordinary
household bleach may be
safely added to bathwater to
reduce the risk of infection. It
may be more convenient for
small children to use a bath
oil containing triclosan.
In addition to this, wash
clothes, towels and sheets in
hot water for four weeks.
This is a laborious process
that should involve the
whole family and close contacts; however, it is safe and
often effective.
In cases of failure, treatment with rifampicin plus
another antibiotic such as
fusidate sodium, flucloxacillin or clindamycin is
usually effective.
Cellulitis
Cellulitis is unusual in
healthy children. It presents
with a rapidly spreading,
tender, erythematous nonscaly rash associated with
fever. It may be associated
with lymphangitis and lymphadenopathy. Occasionally
blistering can occur.
The causative organism in
spontaneous rapidly spreading cellulitis is almost always S
pyogenes, but S aureus is
important when cellulitis surrounds a wound. Although
older textbooks mention H
influenzae, vaccination programs have made this a rare
cause of cellulitis.
Cellulitis in children is
often periorbital or associated with herpes simplex
infections, wounds or insect
bites. Children with vascular malformations with a
lymphatic element are also
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How to treat – skin infections and infestations in children
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prone to cellulitis in the affected limb.
Cellulitis should always be treated
with systemic antibiotics using penicillin
and adding flucloxacillin if there is an
associated wound. It is often not possible
to obtain a positive culture, but it is reasonable to assume S pyogenes and treat
accordingly. If the child is allergic to
penicillin, use cephalexin or clindamycin.
Treatment should be continued for 10
days, as trials have shown that five days’
therapy does not eradicate streptococci and
is not sufficient to prevent post-streptococcal glomerulonephritis. This organism is
more sensitive to antibiotics than staphylococcus, and bd treatment schedules are
effective.
If the child seems systemically unwell or
is not responding to oral therapy after 48
hours it is best to send them to hospital for
IV therapy.
Genital streptococcal infections
Most genital infections in prepubertal children are due to infection with group A
streptococcus. Streptococcal perianal dermatitis in children presents with a persistent perianal eruption. The rash is itchy
and tender and may be complicated by
painful fissuring. There is usually welldefined erythema, with scaling or weeping, which may extend several centimetres
from the anal verge. Bleeding and discharge
may occur.
Acute balanitis and vulvovaginitis in
children are most often due to the same
organism. They may occur in conjunction with perianal lesions or in isolation.
Confirmation of the condition should be
made by skin swab, and vaginal swab
in cases of vulvovaginitis. Treatment is
with oral penicillin, cephalexin or roxithromycin for 10 days. Concurrent use
of mupirocin 2% prevents recurrence.
Streptococcal balanitis.
Fungal infections
Tinea
TINEA is caused by fungi
called dermatophytes.These
micro-organisms affect skin,
hair and nails but are never
systemic. The lay term for this
infection, ‘ringworm’, is a misnomer but reflects the fact
that the typical rash is annular
or at least arcuate.
Despite this, tinea has many
atypical presentations, particularly if it has been treated
with topical corticosteroids,
and can easily mimic eczema.
The classic itchy round lesion
with a scaly definite edge and
central clearing as it expands
can be lost readily. Tinea is
often difficult to distinguish
from dermatitis, psoriasis and
other annular or patchy conditions such as pityriasis rosea
and granuloma annulare.
In children, tinea most commonly involves the scalp, face
and body. In children, tinea is
commonly acquired from
dogs, cats, pet mice and
guinea pigs, but human
pathogens may also be
responsible, especially in the
case of tinea pedis. Animal
dermatophytes tend to produce a more inflammatory
and acute form of tinea.
Tinea of hair-bearing
areas presents with patchy
alopecia, scaling and broken
hairs. Rarely, particularly
when the scalp is infected
with an animal fungus, there
can be an exuberant inflammatory reaction called a
kerion, which can easily be
mistaken for an abscess.
However, despite the alarming appearance, the child
remains well and afebrile.
Tinea of the hands, feet and
nails is very uncommon in
children but when it does
occur there is almost always
an adult family member who
has the same infection. It is
also often seen in children
with Down syndrome. As in
adults, it presents with interdigital maceration, scaling and
nail dystrophy. The incidence
rises with age, reaching adult
levels by late adolescence.
Author’s case study — pet-related dermatophyte infection
KATE, 10, was given a guinea pig. Two weeks afterwards she noticed itching on the right side of
her scalp and within a few days her hair started to fall out. The scalp became very inflamed and
swollen but she did not feel particularly unwell and was not febrile.
When a large bald area developed, her parents took her to the accident and emergency
department. After a surgical opinion, Kate was taken to theatre with a provisional diagnosis of an
abscess and an attempt was made to drain the lesion. However, at operation the surgeons were
surprised to find no collection of pus.
The next day the dermatology team was consulted, and pulled hairs and skin flakes were sent
for culture and microscopy. Fungal hyphae were demonstrated. Kate was started on oral
griseofulvin 20mg/kg/day, the drain was removed and she was sent home. She was instructed to
wash her hair using ketoconazole shampoo.
Fungal culture eventually demonstrated the dermatophyte Trichophyton mentagrophytes. The
source was the guinea pig.
Progress was slow. A month later, there was no sign of regrowth, and Kate’s mother had
developed an itchy scaly rash on one hand, which also appeared to be tinea. This was treated
with topical terbinafine cream bd for two weeks and Kate’s medication was changed to oral
terbinafine 125mg/day.
Terbinafine is a fungicidal drug, as opposed to griseofulvin which is fungistatic. Although much
more expensive and with more potential side effects than griseofulvin, terbinafine was essential to
effect a cure in this case.
It took six months for Kate’s hair to grow back, but she eventually recovered without any
permanent sequelae. The guinea pig was returned to the pet shop.
A
Candida infection
C
D
A: Tinea; B: Tinea capitis; C: Tinea pedis; D: Tinea unguum.
Management
Diagnosis is confirmed by
microscopy and culture of
skin scrapings, subungual
debris, clipped nail or plucked
hair, which is simple and inexpensive although the results of
the culture may take 3-4
weeks. Confirming the diag-
28
B
sary for tinea that is widespread, has failed or recurred
after topical therapy or has
been previously treated with
corticosteroids.
The safest and most widelyused agent in children is griseofulvin, used at a dose of 1020mg/kg/day up to a dose of
500mg/day until the rash has
cleared and cultures are negative, but usually for a minimum of four weeks. Griseofulvin tablets should be
crushed and given with fatty
food.
Terbinafine, itraconazole
and fluconazole may also be
used in children if griseofulvin is ineffective. At the end
of the treatment period the
culture should be repeated. If
the culture is now negative
and hair has regrown and
there is no scalp inflammation, stop treatment.
If the culture is positive,
continue therapy, repeating
the culture every 4-6 weeks.
Therapy may be stopped
when a negative culture is
obtained and hair has
regrown. Occasionally this
may take several months. Permanent alopecia is unusual as
a sequel of tinea capitis.
Ketoconazole and selenium
sulfide shampoos reduce shedding of spores and are a useful
adjunct to therapy; however,
used alone they are ineffective
as treatment.
Use of antibiotics, oral corticosteroids and surgical
debridement does not add to
the management of kerion.
| Australian Doctor | 7 November 2008
nosis is useful before treatment with antifungals, particularly if systemic agents are
being used, as tinea can mimic
other conditions.
False negatives can occur
and if there is still a strong
diagnostic suspicion, a trial of
therapy is the ultimate diagnostic tool, and treatment
may be started while waiting
for culture.
Treatment of uncomplicated tinea corporis in children can usually be achieved
with topical therapy using any
of the imidazole creams such
as cotrimazole, bifonazole,
econazole, ketoconazole or
miconazole or, alternatively,
terbinafine cream. There are
various regimens but, as a
general rule, using the cream
until the rash has disappeared
and then another week thereafter usually results in success.
Nystatin cream is not active
against tinea.
Oral therapy is recommended for tinea in hair-bearing areas, the palms and soles
and nails. It is usually neces-
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Candida albicans infection of
the skin and mucosal surfaces
is usually only seen before
puberty in the setting of
babies and young children in
nappies. It is not a cause of
genital rashes in older children, and candida vulvovaginitis is not seen before
puberty.
Otherwise-healthy infants
may develop oral candidiasis.
Generalised cutaneous candida may be seen in healthy
vaginally delivered newborns
whose mothers have vaginal
candidiasis. This presents as a
generalised, erythematous
scaly rash with pustules.
More often candida presents as patches of moist, confluent erythema with a soggy,
scaly edge, sometimes with
vesicles and satellite pustules.
It is commonly found as a
superinfecting complication
on nappy rash. On mucosal
surfaces, curd-like white material is seen on a red base.
Diagnosis is readily confirmed
by culture of a swab or a
scraping for microscopy.
Candida is easily treated
with any topical antifungal
agent, including nystatin;
however, it is important to
realise that oral griseofulvin is
ineffective. The addition of
topical 1% hydrocortisone is
useful to settle inflammation.
Pityriasis versicolor
Pityriasis versicolor is a
common condition in children
and teenagers, caused by
malassezia yeasts, which are
normal commensals of the
skin. It is common in tropical
climates and is exacerbated by
heavy sweating.
The typical rash presents
as very well-demarcated
small patches of hyperpigmentation or hypopigmentation, with fine scale. It usually occurs on the upper
trunk in teenagers but in
prepubertal children is often
on the cheeks and temples,
where it can be easily mistaken for dermatoses such as
pityriasis alba.
The rash is usually asymptomatic and the most patients
complain of is very mild itch.
Treatment is usually requested
for cosmetic reasons. Diagnosis is made by skin scrapings,
which reveal spherical budding yeasts and coarse mycelia
on microscopy, but the clinical
appearance is usually diagnostic.
Pityriasis versicolor is easily
treated with any imidazole
cream; however, 2.5% selenium sulfide shampoo (Selsun)
is also effective. It is also possible to treat with oral agents,
using fluconazole or itraconazole; however, this is rarely
required in children. Griseofulvin is ineffective.
If the rash is hypopigmented, this may persist for
some months until adequate
sun exposure repigments the
areas of pallor. Pityriasis versicolor is often recurrent,
and repeated courses of
treatment may be necessary.
Alternatively, using selenium
sulfide 2.5% or ketoconazole 2% shampoos weekly
in the shower will be effective as a preventive agent.
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Viral infections
Warts
WARTS are benign, virally
induced tumours seen most
commonly in children.
Common warts usually occur
on the hands and around the
nails, feet and extensor surfaces. Facial warts often take
the form of multiple, tiny,
plane, brown or fleshcoloured lesions. Warts near
the mouth, on the nose and
around the genital area are
frequently filiform. Nail biters
often transfer finger warts to
their faces.
There is no specific or reliably effective treatment for
warts, and all therapies have a
failure rate. In children warts
frequently resolve spontaneously within two years,
making aggressive therapy
inappropriate. It is imperative
never to make the treatment
worse than the disease and to
make sure parents understand
the nature and natural history
of warts before embarking on
therapy. Also make sure it is
the child, not the parent, who
wants treatment.
There are many over-thecounter products for warts.
These often rely on keratolytics such as salicylic acid, or
anti-mitotics
such
as
podophyllum resin. Other
reported treatments include
soaking the warts in formalin
and occluding them with tape.
Plane warts sometimes seem
to respond to topical tretinoin
0.05% cream. Oral cimetidine
has been reported to be a successful treatment in children
at high dose (40mg/kg/day),
but reports are anecdotal and
there are no randomised controlled trials to support its use.
Ablative therapy with liquid
nitrogen has a reasonable success rate but is too painful for
many children to cope with.
Methods such as cautery,
excision and CO2 laser are
well reported but cause scarring and again are significantly
painful.
Topical imiquimod has a
good success rate for genital
warts but is disappointing
when used for common warts.
Its expense coupled with poor
success rate tends to produce
disappointed and resentful
parents.
Several other treatments are
used by specialists. These
include bleomycin injection
and immunotherapy with the
topical sensitiser diphencyprone (DCP). Both are
effective but can be hazardous. Bleomycin injection in
a child requires a general
anaesthetic because it is so
painful, while DCP carries the
risk of severe allergic contact
dermatitis.
Cantharidin is a substance
that can be applied to warts in
the surgery and subsequently
produces a blistering reaction.
It can be complicated by pain
and sometimes infection. Nevertheless, for patients who are
determined enough to rid
themselves of warts to see a
Warts.
Plane warts.
Mollusca.
Herpes simplex.
Varicella.
Herpes zoster.
Hand, foot and
mouth disease is
usually mild but
occasionally it
may be a severe or
even fatal disease,
complicated by
meningitis,
myocarditis and
respiratory failure.
dermatologist, all these
modalities can occasionally be
useful.
Molluscum contagiosum
This is another very common
viral infection, which can
occur anywhere on the body.
The virus is spread in water
and infection is usually
acquired in public swimming
pools, then transferred to siblings in the bath. The typical
lesion is a pearly papule with
central umbilication and a
core that may be extracted
with firm pressure or, if the
child is brave, with the tip of a
needle.
At times it can be quite difficult to diagnose, and particularly when there are only one
or a few lesions mollusca can
mimic naevi and other minor
growths. A micropapular
form occurs that can look like
folliculitis. Atrophic scarring
may occur whether the lesions
are treated or not.
Molluscum contagiosum
usually resolves spontaneously
in immunocompetent patients,
but may take up to two years.
The infection may be complicated by dermatitis, particularly in atopic patients, and by
bacterial superinfection.
It is not practicable or necessary to isolate children with
molluscum contagiosum, but
showering rather than bathing
does at least reduce the spread
of the virus at home.
Management
This condition is always selflimiting in healthy children,
and the best course of action
is often simply to wait for it to
resolve.
Most chemical therapies are
ineffective. Topical imiquimod
has been well described as a
treatment but the success rate
is far from 100%, and treatment is expensive and irritating. In children, conservative
management (ie, waiting for
spontaneous resolution) is
usually best, unless lesions are
widespread and interfering
with lifestyle and function.
Any ablative therapy works
— squeezing the lesions,
extracting the core with a
curette or needle, cryotherapy,
and even laser — but, as for
warts, keep this in perspective
and never make the treatment
worse than the disease. If it is
the parent not the child who is
worried, encourage them to
wait for spontaneous resolution.
Showering rather than
bathing reduces self innoculation and spread to other siblings. Treat secondary infection and dermatitis if present
and do little more.
Herpes simplex infection
Herpes simplex virus infections are very common in children, and the primary attack
often occurs in childhood,
with fever, toxicity and oral
ulceration associated with
lymphadenopathy. Healing
occurs in two weeks, but
during this time it may be difficult for the child to eat and
drink, and hospitalisation may
be required.
Recurrent attacks usually
occur on the lips, but if the primary attack has been on the
skin, recurrences can occur on
that area of skin. Recurrences
are usually mild and infrequent but occasionally are very
frequent and disabling. Sun
protection is important in preventing recurrences of facial
herpes simplex.
Coxsackie viruses may also
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cause oral ulceration (herpangina and hand, foot and
mouth disease). The diagnosis of herpes simplex, if in
doubt clinically, can be confirmed by PCR or rapid
immunofluorescence. Viral
culture is also useful, but it
may take several days to grow
the virus.
Mild cases can be treated
symptomatically, but in children with atopic dermatitis
and in immunosuppressed
patients, herpes simplex virus
may disseminate, causing a
generalised eruption requiring
hospitalisation and antiviral
therapy.
Herpes simplex infection
may be complicated by erythema multiforme, which is
often more disabling than the
infection itself, and this also
requires antiviral therapy.
Occasionally herpes simplex
infections can be complicated
by cellulitis and lymphangitis.
Infections on the eyelids may
be complicated by periorbital
cellulitis.
For primary attacks, dissemination, erythema multiforme and very frequent
recurrences, particularly near
the eyes, systemic treatment is
indicated. Aciclovir may be
given to children orally or
intravenously. Although there
are few data on use of valaciclovir, there would appear to
be no reason why it should
not be given, as it is metabolised to aciclovir in the
body, is much better absorbed
and has a much easier dosing
schedule. The only real reason
to give aciclovir IV is inability
to swallow.
Varicella (chicken pox) and
herpes zoster (shingles)
Varicella is becoming much
less common because of
immunisation but still exists
in the community.
The rash of varicella is classic and invariable, consisting
of a febrile prodrome, sometimes with a non-specific maculopapular eruption followed
by crops of clear vesicles
which become purulent, then
indented and then crust over.
A good clue is lesions on the
scalp and also mucosal surfaces. What is not consistent is
the severity of the rash, which
can vary from just a few
lesions to a severe, generalised
eruption.
Children with a normal
immune system usually survive varicella without treatment, although significant
scarring can occur and is
unpredictable. Those who are
immunosuppressed or who
have existing skin disease such
as atopic dermatitis are more
at risk for severe disease with
complications, and in such
children antiviral treatment is
warranted. Bacterial superinfection may occur.
Varicella in the nonimmune can be prevented
after exposure to an infected
patient by administering either
varicella vaccine within five
days of exposure, or high-titre
varicella-zoster immune globulin (ZIG) within 96 hours of
exposure.
Herpes zoster (shingles) is
caused by reactivation of the
varicella-zoster virus. It can be
seen in children and may be
seen in the first two years of
life if there has been a history
of maternal varicella. Most
children with herpes zoster are
not immunosuppressed.
This condition is infective
in the vesicular stage, and
exposure may result in varicella in non-immune contacts.
The eruption presents with
dermatomally distributed blisters on an erythematous base.
Lesions erupt over a week and
then heal over two weeks.
Pain is usually minimal in
children and can be managed
with simple analgesics.
Antiviral treatment can be
used in children seen within
72 hours of the onset of vesicles, and should be used in all
patients with ophthalmic
herpes zoster and in immunocompromised patients. An
ophthalmology referral should
be made if the eyelid is
involved.
Hand, foot and mouth
disease
This is a common vesicular
exanthem caused by coxsackie
A virus. Mildly painful blisters occur in the mouth as
well as on the hands and feet,
although the rash may be
more extensive, involving the
legs and buttocks. In children
with atopic eczema it may
generalise. The attack lasts
about a week.
Hand, foot and mouth disease is usually mild but occasionally it may be a severe or
even fatal disease, complicated
by meningitis, myocarditis and
respiratory failure.
Parvovirus infection
(slapped-cheek disease,
erythema infectiosum)
This eruption presents initially
with a confluent facial rash
followed by a generalised
maculopapular rash most
obvious on the arms and legs
and classically developing a
reticulated appearance. However, the rash is not diagnostic, and other viral rashes can
look similar. The eruption may
come and go for 2-3 weeks.
In children arthralgias are
very uncommon and the
infection is a benign condition. Nevertheless, cases of
aplastic anaemia have been
reported and infection in
the first trimester of pregnancy can result in
intrauterine death.
The disease can be diagnosed by the finding of specific IgM, which may be present for 2-3 months after
acute infection. When there is
a pregnant woman in close
contact with the infected child,
this is worth investigating.
cont’d next page
7 November 2008 | Australian Doctor |
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How to treat – skin infections and infestations in children
Infestations
Head lice
HEAD lice are endemic in
Australia, are a specific
human pathogen and are a
common problem in school
children. The infestation is
most often noticed because
of eggs attached to the hair
shaft. Itching of the scalp is
the usual symptom and cervical lymphadenopathy is
common.
Head lice are treated by
application of topical insecticides. In the past, permethrin and maldison have
been the treatments of
choice; however, resistance
to head lice treatments is a
problem not only in Australia but worldwide, and
new treatments are currently
under investigation.
Some cases can be cured
by wet combing (applying
hair conditioner to wet hair
and using a fine nit comb)
every day for 10-14 days
until no lice are found. This
method has only about a
40% success rate. Heat may
be effective, using a
hairdryer. Oral sulfamethoxazole-trimethoprim or oral
ivermectin may be used in
very resistant cases.
All lice treatments should
be repeated after 7-10 days,
and the conditioner and
combing method (above)
should be used the next day
to check there are no further
live lice on the scalp. In
between treatments use the
same combing method twice,
removing all eggs <1.5cm
from the scalp with a headlice comb or by pulling them
off with fingernails. These
eggs may contain viable
larvae. Wet combing should
be repeated weekly for several weeks after cure to
detect recurrence.
Washing of pillow cases,
combs and brushes in hot
water (60°C) is important.
Family and close physical
contacts should be examined
and treated if live lice are
found. The patient’s school
should be notified but it is
not necessary to exclude
children with head lice from
school after initial treatment.
The presence of nits on the
hairs >1.5cm from the scalp
indicates previous, not
active, infestation.
Scabies
Scabies is caused by infesta-
Practice points — bacterial infections
■
Resistance to
head lice
treatments is a
problem not only
in Australia but
worldwide.
■
■
■
■
■
The most common cause of skin infections in children is
Staphylococcus aureus
Most bacterial skin infections in children are mild and easily
treated
It is common for S aureus infections to become recurrent or
chronic as a result of a carrier state that can involve the
whole family
Community-acquired MRSA is becoming more common and
it is becoming increasingly important for GPs to document
staphylococcal infection with culture
Almost all genital infections in prepubertal children are due to
beta-haemolytic group A streptococcus
Cellulitis should always be treated with systemic antibiotics,
however Streptococcus pyogenes is more sensitive to
antibiotics than S aureus and can be treated with bd dosing
Practice points — fungal infections
Tinea (dermatophyte infection) is common in young chidren
and is usually acquired from pets such as guinea pigs, mice
and cats
■ Tinea may cause a very inflammatory scalp lesion with loss of
hair; however, even though the condition appears dramatic,
the child remains systemically well
■ Candida albicans rarely causes rashes other than nappy rash
in healthy children
■ In children pityriasis versicolor usually presents as depigmented facial macules
■
tion with the mite Sarcoptes
scabiei var. hominis, a
human pathogen spread by
close physical contact
between infested persons.
Human scabies is not
acquired from animals.
Untreated it will usually
spread to all members of a
patient’s family and other
close contacts.
Scabies is common in
school-age children and is a
very big problem in Aboriginal and South Pacific
Islander communities. These
racial groups are also more
prone to secondary streptococcal infection, which in
turn can lead to glomerulonephritis. It has been
shown that having access to
a public swimming pool
reduces bacterial skin infections in these communities.
The rash of scabies is
highly variable and this can
make it difficult to diagnose.
There may be virtually no
signs apart from itching that
is most severe at night. A
vesicular or pustular eruption
on the palms and soles is
characteristic in babies, but a
non-specific excoriated rash
on the trunk or scattered
nodules may also be present.
The diagnostic lesion is a
burrow in which the mite
lives and lays eggs. It is typically found between the fingers or on the wrists. This
lesion, which is superficial,
may be gently scraped off
with a scalpel, smeared on a
glass slide and examined
under a microscope. This
procedure does require some
skill, particularly in selecting
the right lesion.
Management
For the topical treatment of
scabies, the treatment of
choice in terms of safety and
efficacy is permethrin 5%
cream, even in babies.
Benzyl benzoate is effective if
used correctly but it is more
irritating than permethrin.
All anti-scabetic treatments
are more effective if used on
two occasions a week apart.
Permethrin is not approved for children under
six months of age; however,
untreated scabies at this age
can be severe. Other treatments said to be useful compared with permethrin
include 10% sulfur cream
and 10% crotamiton cream,
each used topically for three
days, although very few
safety data are available.
In resistant cases ivermectin may be used at a
dose of 200μg/kg orally as a
stat dose. Ivermectin is not
approved for use in children
under five years of age, as
safety in this group has not
been established.
The usual recommendation is to apply the treatment
from the neck down; however, scabies above the neck
is common in central and
northern Australia and in
infants, and in this situation
treatment should also be
applied to the face and hair
(avoiding eyes and mucous
membranes).
Clothes, towels and bedding should be washed or
subjected to heat from an
iron or a hot clothes dryer. If
this is not possible they can
simply be stored for a week,
as the mites survive for a
maximum of 36 hours away
from the host.
Contact tracing, notification and treatment are essential to prevent treatment failure. All members of the
patient’s family and close
contacts should be treated
simultaneously. If a schoolage child has had scabies,
the school should be notified, but treatment of clinically uninvolved children is
not required. Infested children
may return to school when
two treatments one week
apart have been completed.
Scabies is a stigmatised
condition. Patients are
often horrified at the diagnosis and say they feel
dirty. It is important to
reassure them that this is
just an infestation and not
a hygiene problem.
The itch of scabies may
not resolve immediately after
treatment, and topical corticosteroids should be prescribed to relieve it. Patients
need to be warned not to
overuse insecticides, as this
often just worsens the itch.
After treatment, many
patients need a lot of reassurance that the infestation
is over.
Practice points —
viral infections
There is still no reliable
treatment for viral warts
■ Genital warts in children
may be a sign of sexual
abuse
■ Molluscum contagiosum
infections are most
responsive to procedures
that extract the viral core:
topical medications are
often disappointing
■
Practice points —
infestations
Head lice are becoming
increasingly resistant to
treatment, not just in
Australia but worldwide
■ Scabies is seen in all
sections of society but is a
serious and endemic
problem in Indigenous
communities, where
secondary infection is also
common
■ The itch of scabies does
not always settle as soon
as it is treated. Use topical
steroids and warn the
patient not to overuse
topical insecticides
■
GP’s contribution
Case study
DR JON FOGARTY
Point Clare, NSW
30
MARK, 13, presents complaining of
“pimples” on his anterior thighs and
both deltoid regions. On examination
he has low-grade folliculitis affecting
both these areas, with an underlying
‘sandpaper’ texture to his skin. He has
had several courses of antibiotics, with
minimal effect.
While there, Mark’s mother asks if
you could “have a quick look at
Aaron”, Mark’s 11-year-old sibling.
| Australian Doctor | 7 November 2008
Aaron has excessively sweaty hands
and feet and has hyperkeratotic skin
on the soles and an offensive smell from
his feet.
The boys’ mother announces that
“the whole family are terrific sweaters”.
Questions for the author
What is the likely diagnosis for Mark
and how is his condition best managed?
It sounds as though Mark has keratosis pilaris, which is why his skin feels
www.australiandoctor.com.au
like sandpaper and why antibiotics have
made no difference. Sometimes this can
look pustular and have the appearance
of a folliculitis, and sometimes it can
be truly superinfected with S aureus.
The way to sort this out is to simply
take a swab from a pustule and send it for
culture. If the report comes back “no
growth”, you are just dealing with a
harmless genetic variant found in half the
population, which can mimic folliculitis.
cont’d page 32
Online resources
■
■
■
Dermnet New Zealand:
www.dermnet.org.nz
American Academy of
Dermatology:
www.aad.org
British Association of
Dermatologists:
www.bad.org.uk
AD_032___NOV07_07 Page 6 30/10/08 3:42 PM
How to treat – skin infections and infestations in children
from page 30
What is the long-term outlook for this condition?
There is not a lot one can
do to change it and it can look
quite inflammatory in adolescence. Keratolytics such as
10% urea cream or 6% salicylic acid in sorbolene can be
used but only reduce the sandpaper feel and make little
impact on the appearance. It is
pretty unlikely that a 13-yearold boy will be too keen on
such treatment, particularly
long term. Philosophical
acceptance is the best way to
deal with it in many cases.
Can you advise on any measures to help deal with
Aaron’s excess sweating?
At age 11 there is not a lot
that can be done. Excess
sweating is not a disease; it
is a variation of the norm
for most healthy young
people. The place to start
with a primary-school child
is with a potent antiperspirant such as Driclor, available at pharmacies. Home
iontophoresis is a possibility, but ask yourself
whether the whole thing is
as distressing to Aaron as
to his mum.
If Aaron has hyperkeratotic
feet, consider the possibility
of tinea or pitted keratolysis.
The former can be diagnosed
with a scraping. Pitted keratolysis has a honeycomb
appearance, which is diagnostic. However, don’t forget
to include psoriasis in the differential diagnosis, particularly if your scraping doesn’t
produce a positive result for a
dermatophyte.
General questions for the
author
Griseofulvin is difficult to
obtain at times. Are there
How to Treat Quiz
2. Which THREE statements about the
management of impetigo and folliculitis are
correct?
a) Skin swabs for microscopy and culture are
not useful for guiding treatment of impetigo or
folliculitis in general practice
b) Topical mupirocin 2% cream or ointment may
be used for localised impetigo
c) When impetigo is widespread or severe it is
reasonable to start therapy with flucloxacillin,
cephalexin or roxithromycin
d) If impetigo is recurrent or resistant to
treatment, chronic carriage of S aureus
should be checked for
3. Which TWO statements about cellulitis in
children are correct?
a) The causative organism in spontaneous,
rapidly spreading cellulitis is almost always S
aureus
b) Cellulitis should always be treated with
systemic antibiotics
You mentioned it is not
standard practice to swab
for impetigo. Do you feel we
should be doing this and, if
not, are there any clinical
signs that would suggest that
a bacterial infection is more
likely to be a streptococcal
rather than a staphylococcal
infection?
We are seeing ever more
community-acquired MRSA
but there is really no way to
tell this clinically from other
staphylococcal infections
other than non-response to
antibiotics. It is easier to tell
streptococcus from staphylococcus. Streptococcus usually produces cellulitis.
When streptococcus is
responsible for impetigo it
often has an ulcerative quality and we call this ecthyma.
If the diagnosis is a streptococcal infection, should we
do routine surveillance as
part of our follow-up (eg,
urine dipstick testing)?
Yes, indeed you should.
Indigenous Australians and
people of Pacific Island
descent are prone to streptococcal infections of skin.
As a result they have a big
problem with glomerulonephritis and even
rheumatic fever is being seen
in Indigenous communities.
I was once told that we
should refer children with
warts to the dermatologist
we like the least! Is this still
sage advice?
No of course not!
Although the best treatment for warts in children
is, in many cases, masterful
indifference, when they are
unsightly or creating emotional problems we have to
do our best to help
patients.
The most effective treatments in my hands are
either diphencyprone (DCP)
immunotherapy or cantharidin. DCP is a substance to which almost
everyone is allergic, so
putting it on the warts
causes a type IV allergic
reaction. The wart is the
casualty while the immune
system attacks the DCP.
Cantharidin is a product
extracted from a ‘blister
beetle’. It is painless to apply
but later causes blood blisters that lift the wart. As you
can imagine, both methods
have their risks and it is perhaps best to leave these to
the specialist.
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answer.
Skin infections and infestations
in children — 7 November 2008
1. Which TWO statements about impetigo
and folliculitis are correct?
a) Impetigo is caused most commonly by
Staphylococcus aureus
b) Certain racial groups, particularly Aboriginal
and South Pacific Islander peoples, are more
susceptible to infection with Streptococcus
pyogenes
c) Ecthyma is a type of impetigo with superficial
blisters caused by S aureus infection
d) Folliculitis is invariably due to infection with S
aureus
any particular safety concerns around alternative oral
antifungal medications?
The availability of griseofulvin has been quite an
issue this year, as it is a very
safe, inexpensive medication
for treating tinea in children.
Three other broad-spectrum
oral antifungals are available: terbinafine, itraconazole and fluconazole.
Terbinafine has the advantage of being the only fungicidal drug available.
All are very well tolerated
and safe medications,
although terbinafine has a
more worrying track record.
There have been cases of
drug-induced hepatitis and
permanent dysgeusia.
However, the main problem with these medications
is the cost. None is PBSlisted for the sort of indications we would require in
treating paediatric skin infections.
ONLINE ONLY
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c) Twice-daily treatment schedules can be used
for infection with S pyogenes
d) Five days’ therapy is adequate for cellulitis
due to S pyogenes
4. Lisa, six years, presents with an itchy,
scaly, well-circumscribed rash on one arm.
Which TWO statements about tinea are
correct?
a) Tinea of the hands, feet and nails is
uncommon in children
b) Nystatin cream is the treatment of choice for
uncomplicated tinea corporis
c) Where an oral agent is required for tinea, the
safest and most widely used agent in children
is griseofulvin
d) Permanent alopecia is a common sequela of
tinea capitis
5. Toby, 14, presents with a rash on the
upper trunk, which is comprised of small,
well-demarcated hypopigmented patches.
Which TWO statements about pityriasis
versicolor are correct?
a) Pityriasis versicolor is caused by malassezia
yeasts, which are normal skin commensals
b) The rash of pityriasis versicolor does not
involve the face
c) Pityriasis versicolor may be treated with an
imidazole cream
d) Pityriasis versicolor is rarely recurrent
6. Abbey, nine, presents with several
common warts on both hands. She is not
bothered by them, but her mother is
concerned about their appearance. Which
THREE statements about warts in children
are correct?
a) Common warts in children frequently resolve
spontaneously within two years
b) It is imperative to make sure parents
understand the nature and natural history of
warts before embarking on therapy
c) There is randomised controlled trial evidence
to support the use of oral cimetidine in the
treatment of warts
d) Genital warts in children may be a sign of
sexual abuse
7. Josh, six, and his younger brother Ben,
four, both have numerous lesions, mainly on
the trunk and limbs. The lesions consist of
raised pearly papules, with central
umbilication. Which TWO statements about
molluscum contagiosum are correct?
a) Molluscum contagiosum spontaneously
resolves by six months
b) Treatment of molluscum contagiosum
prevents development of scarring
c) Showering rather than bathing is helpful in
reducing spread of the virus to siblings
d) In children, conservative management, ie,
waiting for spontaneous resolution of
molluscum contagiosum, is usually best
8. Which TWO statements about varicellazoster virus infection are correct?
a) Antiviral treatment is warranted in
immunosuppressed children with varicellazoster virus infection
b) After exposure to an infected patient, varicella in
the non-immune can be prevented by use of
varicella vaccine up to one week after exposure
c) Most children who develop herpes zoster are
immunosuppressed
d) Exposure to patients with herpes zoster in the
vesicular stage may result in varicella infection
in non-immune contacts
9. Ginny, seven, has head lice for the second
time in the last couple of months. Which
TWO statements about head lice are correct?
a) Head lice are becoming increasingly resistant
to treatment
b) All lice treatments should be repeated 7-10
days later
c) Children with head lice should be excluded
from school for 7-10 days after treatment
d) The presence of nits on the hairs more than
1.5cm from the scalp indicates active
infestation
10. Which TWO statements about scabies are
correct?
a) Scabies never affects the face or scalp
b) Permethrin 5% cream is the topical treatment
of choice for scabies but is not approved for
use in babies under six months of age
c) If a child has scabies, the school should be
notified, and all children in the same class
should be treated regardless of whether they
are symptomatic
d) The itch of scabies may not resolve
immediately after treatment, so topical
corticosteroids may be used to relieve it
CPD QUIZ UPDATE
The RACGP now requires that a brief GP evaluation form be completed with every quiz to obtain category 2 CPD or PDP points for the 2008-10 triennium. You
can complete this online along with the quiz at www.australiandoctor.com.au. Because this is a requirement, we are no longer able to accept the quiz by post
or fax. However, we have included the quiz questions here for those who like to prepare the answers before completing the quiz online.
HOW TO TREAT Editor: Dr Wendy Morgan
Co-ordinator: Julian McAllan
Quiz: Dr Wendy Morgan
NEXT WEEK Although hepatitis B virus (HBV) vaccination is on the Australian immunisation schedule, the number of Australians with HBV infection is predicted to increase over the next 5-10 years. Those
with chronic HBV infection are at increased risk of developing cirrhosis, liver failure and hepatocellular carcinoma. The next How to Treat is a timely review of the diagnosis and management of HBV infection.
The author is Dr Gordon Jung-Hyuk Park, visiting gastroenterologist and hepatologist, Royal North Shore Hospital, St Leonards and Concord Hospital, Concord, New South Wales.
32
| Australian Doctor | 7 November 2008
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