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Paediatric dermatology

Paediatric dermatology

 

Atopic dermatitis in children

 

Introduction

Atopic dermatitis is the most common chronic skin condition affecting young children. Onset is most often in the first year of life, with xerosis, itching and a patchy erythematous rash which may occur on any part of the skin but is most often found on the face, cubital fossa and popliteal fossa. Children with atopic dermatitis are sensitive to environmental irritants and allergens and are prone to cutaneous infections. Management of this condition therefore has the following components: encouraging compliance; prevention (environmental modification and control of xerosis); treatment (specific medical management, control of infection, as well as investigation and management of allergy, although not applicable in every case).

 

Compliance and atopic dermatitis in children

 

It cannot be stressed too highly that this is a chronic condition. Parents must comprehend the chronicity of this condition, the need for continuous suppressive therapy at times of activity, and ongoing preventative environmental modification at times of apparent normality.

Treatment failure often occurs because therapy is ceased as soon as the dermatitis clears, in the belief that a ‘cure’ has been achieved. When the inevitable relapse occurs, this leads to the belief that treatment has been a failure and subsequent abandonment of therapy. Another common reason for treatment failure is apprehension regarding the use of topical corticosteroids. Parents need to be reassured that if used correctly they have a good safety record.

In order to encourage compliance:

           educate parents regarding the nature of the condition

           prognosis and medication

           devise a simple

           easy to execute regimen of treatment

           attempt to minimise cost to the patient

           provide written information on the management of remission and exacerbation

           provide written information on environmental modification

           follow up regularly.

Environmental modification for atopic dermatitis in children

 

           Soap, shampoo and bubble bath should be eliminated.

           Skin contact with woollen and acrylic clothes, blankets and toys should be avoided. Substitute cotton and cotton blends.

           Dust should be minimised by using a plastic mattress cover and pillow covers, eliminating dust-catching objects (fluffy toys, curtains and carpets) and vacuuming thoroughly. If the child has to sit on the floor at school, a mat should be used. In very severe cases, removing carpet and curtains may be indicated.

           Contact with sand should be avoided.

           After swimming in a chlorinated pool, the patient should wash immediately and apply emollient.

Compliance and atopic dermatitis in children

 

It cannot be stressed too highly that this is a chronic condition. Parents must comprehend the chronicity of this condition, the need for continuous suppressive therapy at times of activity, and ongoing preventative environmental modification at times of apparent normality.

Treatment failure often occurs because therapy is ceased as soon as the dermatitis clears, in the belief that a ‘cure’ has been achieved. When the inevitable relapse occurs, this leads to the belief that treatment has been a failure and subsequent abandonment of therapy. Another common reason for treatment failure is apprehension regarding the use of topical corticosteroids. Parents need to be reassured that if used correctly they have a good safety record.

In order to encourage compliance:

           educate parents regarding the nature of the condition

           prognosis and medication

           devise a simple

           easy to execute regimen of treatment

           attempt to minimise cost to the patient

           provide written information on the management of remission and exacerbation

           provide written information on environmental modification

           follow up regularly.

Environmental modification for atopic dermatitis in children

 

           Soap, shampoo and bubble bath should be eliminated.

           Skin contact with woollen and acrylic clothes, blankets and toys should be avoided. Substitute cotton and cotton blends.

           Dust should be minimised by using a plastic mattress cover and pillow covers, eliminating dust-catching objects (fluffy toys, curtains and carpets) and vacuuming thoroughly. If the child has to sit on the floor at school, a mat should be used. In very severe cases, removing carpet and curtains may be indicated.

           Contact with sand should be avoided.

           After swimming in a chlorinated pool, the patient should wash immediately and apply emollient.

 Control of xerosis in atopic dermatitis in children

 

Dispersible bath oil should be used in the bath daily, and soap and shampoo substitutes used, see Table 1. An emollient should be applied over the whole body. The frequency of use will depend on the degree of xerosis. For mild xerosis, application after bathing is sufficient. For more severe xerosis, application 2 or 3 times daily is recommended. Emollients are easiest to apply if used on wet skin after bathing.

 

 

Bath additives and soap substitutes (Table 1)

bath additives

oatmeal, QV bath oil, Dermaveen shower and bath oil, Alpha Keri bath oil, Hamilton bath oil, Oilatum bath additive

soap substitutes

sorbolene cream, emulsifying ointment, Oilatum shower gel, QV wash and QV bar, Dermaveen cleansing bar, Cetaphil lotion and cleansing bar, Hamilton body wash and cleansing lotion

 

Choice of emollient

Numerous emollients are available and the choice depends on:

Xerosis severity: use greasier emollients for more severe xerosis.

Climate: a less greasy product is needed in hot, humid weather.

Adverse effects: some emollients (eg sorbolene cream) can cause stinging, which can lead to noncompliance and loss of confidence in treatment. Try the moisturiser to determine if there is a problem prior to purchase.

Cost: large amounts of emollient are required and compliance is more likely if the cost is minimised. Simple inexpensive preparations are as effective as proprietary compounds [Note].

Recommended over-the-counter preparations are QV cream, Dermaveen lotion or Dermadrate cream (useful for severe xerosis but may sting).

 

Emollient strength (Table 2)

sorbolene with glycerol (glycerin) 10%

medium strength (greasiness); inexpensive; readily available; sticky and may cause stinging

eucerin (wool alcohols) ointment

greasy; useful in severe xerosis; rarely stings; sticky feel

emulsifying ointment

vary strength by adding water; good patient acceptance; may sting

aqueous cream

medium strength; pleasant feel; rarely stings; vary consistency with white soft paraffin, paraffin, peanut or olive oils [Note]

white soft paraffin

very greasy; inexpensive; readily available; rarely stings; vary strength with aqueous cream [Note]

Topical corticosteroid use in atopic dermatitis in children

 

General recommendations for the use of topical corticosteroids are as follows. The topical corticosteroid should be applied daily to any areas of active dermatitis, titrating the strength of the preparation and the frequency of application to the severity of the dermatitis. An emollient should be applied to the entire skin before application of the corticosteroid to areas of active dermatitis. Patients should have a range of topical preparations. If there has been no response to a milder preparation after 3 days, a stronger one should be used.

Note

In general, corticosteroid ointments are preferable to corticosteroid creams as they are more effective and less likely to sting.

Corticosteroids may be used under wet dressings in severe cases; however, this frequently requires hospitalisation.

Only hydrocortisone 1% should be used on the face and flexures, unless the severity of the condition warrants the use of stronger preparations for short periods under close supervision.

Corticosteroids should be continued until the skin has normalised and then ceased until there is evidence of further dermatitis. Breaks from therapy, even if brief, are important to avoid tolerance to the effect of the corticosteroid.

Control of infection in atopic dermatitis in children

 

The most common infections seen in children with atopic dermatitis are: impetigo (usually due to Staphylococcus aureus, occasionally group A streptococcus); herpes simplex; molluscum contagiosum.

Infection commonly exacerbates atopic dermatitis, and control of infection is essential before the dermatitis can be effectively treated. For specific therapy of acute infection, see Infectious diseases.

In many cases, the child is chronically colonised by Staphylococcus aureus. This results in exacerbation of dermatitis, difficulty controlling dermatitis, and crusting and folliculitis. When this is encountered, cutaneous and nasal bacterial swabs should be taken.

If herpes simplex is suspected clinically (grouped vesicles or erosions), viral swabs should be taken.

For bacterial infections, the recommended therapy is

daily use of medicated bath oil OR chlorhexidine 5% solution 5mL in bath water with bath oil

AND

mupirocin 2% ointment or cream topically, to any crusted areas twice daily for 7 days

AND

mupirocin 2% nasal ointment intranasally, twice daily for 7 days, if nasal carriage has been confirmed.

 

An initial swab is useful to determine the presence and sensitivities of Staphylococcus aureus, and a nasal swab is useful to detect nasal carriage. Oral antibiotics are used in the situations described below.

           When the dermatitis has not settled with other measures and there is suspicion that infection is contributing to the dermatitis.

           When there is obvious secondary infection, particularly if using wet dressings.

Oral antibiotics aimed at Gram-positive organisms should be used for 7 days. Use

di/flucloxacillin 12.5 to 25mg/kg up to 500mg OR cephalexin 12.5 to 25mg/kg up to 500mg orally, 6-hourly

OR

erythromycin 7.5 to 12.5mg/kg up to 500mg OR roxithromycin 2.5 to 4mg/kg up to 150mg orally, 12-hourly (for sensitive organisms).

 

For sensitive strains, trimethoprim can be used.

 

Oral immunosuppressive therapy in atopic dermatitis in children


In general, oral immunosuppressive therapy is neither appropriate nor necessary for treatment of atopic dermatitis in children.

Oral corticosteroids are contraindicated, as severe rebound is usually experienced on withdrawal, and repeated courses destabilise the dermatitis and can result in erythroderma. This situation is completely different to treating acute exacerbations of asthma.

Oral cyclosporin, although described in the literature for treating very severe atopic dermatitis, is not approved for this use in children in Australia. Consultation with an immunologist or paediatrician would be required before embarking on this therapy.

Allergy testing in children with atopic dermatitis

 

The child should be considered for allergy assessment in the following situations: the dermatitis is severe or difficult to control; parents report exacerbations in relationship to particular foods or formula; the dermatitis has an urticarial component; the dermatitis is distributed on exposed areas, particularly the periocular area and the face, indicating the role of an aeroallergen.

A child with suspected food allergies should not be placed on a restrictive diet without allergy assessment and advice from a dietitian.

Prognosis and long-term management in atopic dermatitis in children

 

In the majority of cases, the prognosis of atopic dermatitis is good, with most children going into remission or substantially improving by the time they enter primary school. The minority still suffer from the condition as teenagers but only a few continue into adult life. Certain environmental situations may bring out the tendency for atopic dermatitis later, for example an occupation such as hairdressing or nursing may result in chronic hand dermatitis. Until remission occurs, parents need to maintain all environmental modification precautions.

The use of moisturisers and soap substitutes should be continued. Topical corticosteroids should be used on a prn basis, depending on the severity of the dermatitis. In general, use hydrocortisone 1% for face and flexures and a moderately potent preparation for body and limbs. Stronger topical corticosteroids should be utilised for intermittent exacerbations.

Parents should watch for signs of infection, such as weeping, crusting and pustules. This requires treatment with antibiotics. If infection is recurrent, a carrier state should be suspected, see Control of infection.

Nappy rash

 

Introduction

Nappy rash is the term used to describe any rash occurring in the area under the nappy. Although the most common cause for a rash in this distribution is a simple irritant dermatitis, there are many other causes, see Table 2. The severity of nappy rash is variable, and it may become so inflammatory that ulceration occurs. In general, the management for all forms of nappy rash is the same, even when very severe.

 

Causes of nappy rash (Table 2)

common

irritant, Candida albicans, seborrhoeic dermatitis, psoriasis, miliaria, atopic dermatitis

uncommon

staphylococcal infection (folliculitis and impetigo), streptococcal vulvitis and perianal dermatitis, herpes simplex

rare

tinea, gluteal granuloma, zinc deficiency, Langerhans cell histiocytosis, Kawasaki disease, congenital syphilis

 

Irritant nappy rash

 

The cause of this is loss of barrier function of the epidermis due to maceration, coupled with irritation from fecal enzymes and applied preparations, including soap and over-the-counter nappy creams. Virtually all cases become colonised with Candida albicans. Management involves two strategies, ie environmental modification and specific medical management.

Environmental modification

           Use disposable nappies with highly absorbent polymers or cloth nappies changed every 2 hours, avoiding the use of plastic overpants and nappy liners.

           Do not use soap. Use a soap substitute and dispersible bath oil.

           Do not use baby wipes. Use a damp cloth and soap substitute.

           Apply simple emollient after every nappy change. Zinc and castor oil cream, or liquid paraffin 10% in zinc paste may be more effective than the emollients outlined in Table 1.

Specific medical management

If the above simple measures are inadequate, the following additional measures are recommended

hydrocortisone 1% cream topically, 3 times daily until the rash resolves, then cease but restart at the first sign of recurrence

PLUS

nystatin 100 000U/g cream OR imidazole cream applied 3 times daily.

 

Nystatin is inexpensive and least likely to produce irritation. The management of all common causes of nappy rash is the same. In general, hydrocortisone 1% is the only corticosteroid that should be used in the nappy area. More potent corticosteroids may induce atrophy, striae or gluteal granuloma. When there has been inadequate response to treatment, the following should be considered: noncompliance with treatment; irritancy or allergy from topical therapy; bacterial or viral infection; psoriasis; underlying rare condition, see Table 2

Bacterial or viral infections in nappy rash

 

The presence of pustules, erosions, ulcers, or areas of weeping may indicate one of the following infections, particularly where there has been an inadequate response to therapy. In this situation, swabbing and culture should be done.

Staphylococcal infection

For minor infection, use

mupirocin 2% ointment applied 3 times daily for 7 days

IN ADDITION TO

hydrocortisone 1% cream topically, 3 times daily until the rash resolves, then cease but restart at the first sign of recurrence

PLUS

nystatin 100 000U/g cream OR imidazole cream applied 3 times daily.

 

If infection is severe, add

di/flucloxacillin 12.5 to 25mg/kg orally, 6-hourly for 7 days

OR

an appropriate oral antibiotic as indicated by sensitivity testing.

 

Note:

Most Staphylococcus aureus infections are resistant to penicillin. Penicillin and amoxycillin are therefore not appropriate.

 

Streptococcal infection

Use

phenoxymethylpenicillin 5 to 10mg/kg OR cephalexin 12.5 to 25mg/kg orally, 6-hourly for 10 days

PLUS

mupirocin 2% ointment or cream applied 3 times daily for 7 days

IN ADDITION TO

hydrocortisone 1% cream topically, 3 times daily until the rash resolves, then cease but restart at the first sign of recurrence

AND

nystatin 100 000U/g cream OR imidazole cream applied 3 times daily.

 

Herpetic infection

This is evidenced by very painful grouped ulcers and erosions (the vesicular phase is often very brief), and oedema is often a prominent feature. A swab should be taken from a fresh ulcer for viral culture.

For mild infection, no specific treatment is required, as the lesions will heal spontaneously within 2 weeks. For severe infection with ulceration or urinary retention, hospital admission for intravenous aciclovir may be necessary.

 Napkin psoriasis

 

In most cases, napkin psoriasis will respond to the measures recommended for nappy rash; however, in some older children a more potent corticosteroid will be required. In this situation the following is recommended.

Induce remission with

a moderately potent to potent topical corticosteroid applied 3 times daily.

 

Maintain with

a low-potency tar preparation, eg LPC 2% in aqueous cream, applied 3 times daily

AND

hydrocortisone 1% cream applied 3 times daily.

Neonatal acne

 

Neonatal acne is the term used to describe acne occurring in infants. It is more common in boys. The acne is frequently predominantly comedonal. Severity is variable and often no treatment is required. The condition is self-limiting, and usually remits by 12 months of age. If the parent desires treatment or if lesions are likely to cause scarring, the following is recommended.

For predominantly comedonal acne, use

tretinoin 0.025% cream applied once daily, increasing to 0.05% once daily, depending on response.

 

If there is an inadequate response to this, or there is an inflammatory component, add

erythromycin 2% gel applied once daily.

 

Oral antibiotic therapy is usually not required, and tetracycline is contraindicated in this age group.

Seborrhoeic dermatitis in children

 

Seborrhoeic dermatitis is a descriptive term denoting a clinical presentation that may occur in a number of common infantile dermatoses.

Note:

Infantile seborrhoeic dermatitis is a different condition to the adult disease of the same name.

 

The eruption is seen early in life, most often before 2 months of age. Initially the face, scalp, neck, axillae and nappy areas are involved, but it may generalise. The lesions are well defined and have a greasy scale. Characteristically, the baby is well and not itchy.

In typical seborrhoeic dermatitis, which is an idiopathic condition, the rash is self-limiting and will clear spontaneously in a few weeks, and more rapidly with treatment. However, follow-up studies show that both atopic dermatitis and infantile psoriasis may present in this way, and in such cases the rash recurs.

Infection with either Candida albicans or Staphylococcus aureus is common and should be suspected if crusting, weeping or pustulation is present. The diagnosis should be confirmed by skin swab and culture.

Soap, shampoo and bubble bath should be avoided and a dispersible bath oil used. For scalp lesions, de-scale the scalp using olive oil or paraffin oil prior to bath, and then use

salicylic acid 2% and sulfur 2% in aqueous cream applied to the scalp at night.

 

For skin lesions, use

a medium strength emollient applied 3 times daily

PLUS

hydrocortisone 1% ointment applied 3 times daily until the eruption has cleared.

 

If Candida albicans is cultured from skin, add

nystatin 100,000U/g cream OR imidazole cream applied 3 times daily.

 

If Staphylococcus aureus is cultured from skin, use

di/flucloxacillin 12.5 to 25mg/kg orally, 6-hourly for 7 days.

 

If there has been no response to therapy after a week, the strength of the topical corticosteroid may be increased to

betamethasone valerate 0.02% OR triamcinolone acetate 0.02%, applied 3 times daily until the eruption has cleared.

 

Follow up is recommended to ensure that this was not the first presentation of a chronic dermatosis.

Pityriasis alba in children

 

This common condition presents as poorly defined hypopigmented scaly patches on the face and upper arms. It is most obvious in summer when the skin is tanned, and in dark-skinned children. It is a mild form of dermatitis in which postinflammatory hypopigmentation is marked. Symptoms are usually minimal. It is more common in atopic subjects.

Avoid contact with skin irritants such as soap and shampoo and use a soap substitute. Apply emollient twice daily, together with

hydrocortisone 1% ointment twice daily to settle irritation and scaling.

 

A sunscreen should be used daily to avoid excess tanning of the noninvolved skin. Corticosteroid treatment will not restore pigmentation, and prolonged use of emollient coupled with graduated sun exposure is required.

Forefoot dermatitis in children

 

This is a relatively uncommon condition seen in children. The anterior part of the sole of the foot, including the ball of the foot and plantar surfaces of the toes, is persistently glazed and fissured. The main complaint is of pain from the fissures rather than itch, which is the predominant symptom in most cases of dermatitis. The condition is resistant to treatment with topical corticosteroids. Occasionally a similar pattern is seen on the fingertips. The prognosis is good and it usually remits by puberty. Avoiding occlusive or tight footwear where possible will be more comfortable, but in general, modifying footwear does little to change the condition. Avoid skin irritants and use a soap substitute. Apply

urea 10% cream or Dermadrate cream twice daily.

Ichthyosis in children

 

Ichthyosis is a genetically determined skin condition that presents at or soon after birth and persists throughout life. It presents with a chronically dry, scaly skin. It is commonly confused with atopic dermatitis, but lacks the itch or inflammatory component unless there is concomitant atopic dermatitis. There are many forms of ichthyosis, both dominantly and recessively inherited, but the most common is ichthyosis vulgaris. In this condition, the entire skin surface is dry and scaly, most obviously on extensor surfaces, particularly the lower legs which may exhibit a ‘crazy-paving’ appearance. The degree of severity is highly variable. The condition is more troublesome in dry winter weather and tends to worsen with age.

Soap, shampoo and bubble bath should be avoided and dispersible bath oil should be used daily. Emollient is required on a daily basis. In general the greasier preparations are more useful, particularly in winter. Patient preference is important, however a preparation containing a keratolytic such as urea 10%, salicylic acid 2 to 6% or propylene glycol 10 to 20% may aid in removing excess scale. Dermadrate, containing sodium pyrrolidone carboxylate, is particularly useful. It is important to note that keratolytics may cause stinging and may be poorly tolerated by children.

Topical corticosteroids are not required in the treatment of ichthyosis, unless there is coincident atopic dermatitis.

Some of the more severe forms of ichthyosis respond to treatment with oral retinoids. This treatment is long-term and involves adverse effects and long-term risks. A child with severe ichthyosis should be referred to a dermatologist for assessment.

 

Psoriasis in children

 

Background and treatment

Psoriasis is less common in children than in adults; however, in 15% of cases the condition appears by the age of 15 years.

In infancy, ‘napkin psoriasis’ presents with a severe well-defined nappy rash, later associated with typical psoriatic lesions on the face, scalp, neck, axillae and body.

In children, psoriasis may present with the typical plaques seen in adults, but usually these are smaller, thinner and less scaly. A common presentation in children is acute guttate psoriasis with acute eruption of small lesions following a streptococcal throat infection. The scalp, retro-auricular folds, face, flexures and genital areas are common presenting sites in children. In the genital areas, only a glazed, well-defined erythema without scaling is seen. Acral psoriasis with nail dystrophy and erythema and scaling of the fingertips may occur in children. It may involve only a few digits or even one digit alone.

Rarely, acute pustular psoriasis may occur in children, with sudden onset of widespread erythema studded with sheets of pustules and associated with fever and systemic toxicity.

Psoriasis is an unpredictable, recurrent or chronic condition. Management may vary depending on site, nature and severity at different stages. Long-term follow up is therefore recommended, as therapy may require revision from time to time.

In general, topical tar preparations are safer in the long term and are usually more effective than topical corticosteroids for treating psoriasis in children; however, their use may be limited by irritancy, cost and poor patient acceptance due to their odour. It is very difficult to generalise regarding treatment of psoriasis and treatment must be individualised. Topical corticosteroids may be used in conjunction with tars, particularly where the rash is itchy.

The following initial therapy is recommended. Commence therapy to lesions on body, limbs and scalp with

LPC 4% and salicylic acid 4% in aqueous cream, applied twice daily

AND

a moderately potent topical corticosteroid applied once daily.

 

If there is scalp involvement, use

a tar-containing shampoo, daily.

 

Commence therapy to lesions on face and flexures with

LPC 2% and salicylic acid 2% in aqueous cream applied twice daily

AND

hydrocortisone 1% cream applied once daily.

 

If there has been a recent streptococcal throat infection, to eliminate antigen use

phenoxymethylpenicillin 10mg/kg up to 500mg OR cephalexin 12.5 to 25mg/kg up to 500mg orally, 6-hourly, for 10 days.

 

Review the patient at 2 weeks for evidence of irritancy. If this is present, reduce the concentration of components of the tar cream. Tell the patient that if irritancy persists, the tar cream should be ceased.

Review the patient again in 4 weeks. The concentration of components of the tar cream should be titrated up or down, depending on response. The maximum concentration is usually LPC 10% and salicylic acid 10%.

If there has been a poor response to this therapy, referral to a dermatologist is recommended, as the use of other treatments in children is complex and beyond the scope of these Guidelines.

In this condition, a slow response to therapy is usual and it is important to warn parents to be persistent. Once the rash has cleared, treatment may be ceased but should be restarted at the first sign of any new lesions. Some patients require ongoing maintenance therapy at regular intervals to achieve control, and this varies from patient to patient.

Although most patients with psoriasis improve with exposure to ultraviolet light, this is not recommended in children because it increases the long-term risk of skin cancer.

Psoriasis in the genital area

Swab the skin for evidence of bacterial superinfection. Treat streptococcal infection with an oral antibiotic, and staphyloccocal infection with topical mupirocin as for nappy rash.

Initiate treatment with

hydrocortisone 1% applied 3 times daily.

 

In toilet-trained children, if there has been a poor response to treatment after a week, use

a more potent topical corticosteroid to clear the eruption.

 

This is usually not necessary in napkin psoriasis.

Once clear, attempt to introduce

LPC 1 to 2% in aqueous cream, and continue this as maintenance therapy.

 

If this is not tolerated, use

hydrocortisone 1% cream as maintenance therapy.

 

A more potent preparation should only be used for acute exacerbations.

Acute pustular psoriasis

Children with this condition should be admitted to hospital and monitored for systemic infection and evidence of dehydration. Weak corticosteroids, wet dressings and oral antibiotics are used for treatment. Recovery may take several weeks.

Streptococcal perianal dermatitis, vulvitis and balanitis in children


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 well-defined erythema, with scaling or weeping, which may extend to several centimetres from the anal verge. Bleeding and discharge may occur. Acute balanitis and vulvovaginitis in children are most often due to Streptococcus pyogenes. 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. Use

phenoxymethylpenicillin 10mg/kg up to 500mg orally, 6-hourly for 10 days.

 

If the child is allergic to penicillin, and the organism is sensitive, use

erythromycin 7.5 to 12.5mg/kg up to 500mg OR roxithromycin 2.5 to 4mg/kg up to 150mg orally, 12-hourly.

 

To prevent recurrence, use

mupirocin 2% ointment or cream applied 3 times daily for 10 days.

 

The eruption may recur. If the rash persists despite therapy, consider an underlying dermatosis with superinfection and treat as appropriate.

Papular urticaria in children


Papular urticaria is a term used to describe hypersensitivity to bites of mosquitoes, fleas, paspalum mites and other insects, and is seen in young children aged between 2 and 6 years. It is a misleading term, as it has no relationship to ordinary urticaria or hives. It usually occurs in spring and summer, and lesions are most often on exposed surfaces, although fleabites usually occur under clothes. Individual lesions are intensely itchy papules, blisters and crusts. Scratching leads to excoriation, infection and ulceration that may result in scarring and hypopigmentation. The prognosis of this condition is good and most children become hyposensitive to the bites after 2 to 4 years.

Minimise exposure to biting insects with insect repellent, protective clothing and insect control, using insecticide, screens and treatment of pets. These strategies must be maintained throughout spring and summer.

Treat infection with

topical mupirocin 2% ointment or cream if mild or an appropriate oral antibiotic (see Control of infection - Atopic dermatitis) if severe

AND

a potent topical corticosteroid applied daily to lesions

PLUS

with wet dressings (see Points on use of modified dressings) to prevent excoriation, until lesions have resolved.

 

Note:

Despite the naming of this condition, oral antihistamines are unhelpful, except as a night-time sedative.

 

Urticaria in children

 

In children, urticaria is most often a benign self-limiting condition. The most common causes are a preceding or current viral illness, foods and medications. Intestinal giardiasis may cause urticaria. Occasionally scabies and fungal infections may be complicated by urticaria. Extensive systemic investigations are rarely indicated.

Commence therapy with an antihistamine at the lowest dose, increasing the dose until the rash is controlled. Use

trimeprazine tartrate 3.75 to 15mg OR promethazine 5 to 10mg orally, 3 times daily

OR

loratadine OR cetirizine 5 to 10mg orally, daily for children <30kg; 10 to 20mg orally, daily for children >30kg.

 

Continue the antihistamine for 2 weeks then gradually withdraw. If the rash recurs, restart the antihistamine and attempt to withdraw it every 2 weeks.

In urticaria persisting for over 6 weeks, a chronic allergen should be considered. Giardiasis should be excluded and consideration given to an elimination diet, see Allergy testing.

Tinea in children

 

 

Introduction

In children, tinea (dermatophyte infection) most commonly involves the scalp, face and body. Tinea pedis is less common in children than in adults, but is seen often in children with Down syndrome. The incidence rises with increasing age, reaching adult levels by late adolescence. In children, tinea is commonly acquired from dogs, cats and guinea pigs but human pathogens may also be responsible, especially in the case of tinea pedis. The animal dermatophytes tend to produce a more inflammatory and acute form of tinea. A kerion is a very acute form of tinea capitis, usually caused by an animal dermatophyte, in which a large boggy, pustular mass appears on the scalp.

 

Tinea capitis, including kerion

These dermatophyte infections like tinea capitis are caused by fungi of the genera Trichophyton, Microsporum and Epidermophyton. Confirm the diagnosis by fungal culture of scrapings and plucked hairs prior to commencing therapy. This is important to confirm the diagnosis and for future monitoring. Topical therapy is ineffective in treating tinea capitis.

1

terbinafine (child <20 kg: 62.5 mg; 20 to 40 kg: 125 mg) 250 mg orally, daily for 4 weeks

 

OR

2

griseofulvin fine particle (child: 10 mg/kg up to) 500 mg or ultrafine particle (child >2 years: 5.5 mg/kg up to) 330 mg orally, daily for 4 to 8 weeks.

 

Hair may not have completely regrown at the end of therapy, but this improves with time. Scarring alopecia is unusual as a sequel of tinea capitis.

Ketoconazole and selenium sulfide shampoos are a useful adjunct to therapy, in that they reduce shedding of spores; however, used alone they are ineffective as treatment.

The use of antibiotics, oral corticosteroids and surgical debridement does not add to the management of kerion and is contraindicated.

 

Tinea corporis, faciei or pedis

Prior to commencing treatment, perform a fungal scraping for culture. Many rashes that are common in children, such as dermatitis and psoriasis, may mimic tinea.

For mild or localised cases, use

imidazole cream applied 3 times daily for a minimum of 3 weeks

OR

terbinafine 1% cream applied twice daily for minimum of 2 weeks.

 

For extensive cases or tinea that has received prolonged treatment with topical corticosteroid, use

griseofulvin fine particle (child: 10 mg/kg up to) 500 mg or ultrafine particle (child >2 years: 5.5 mg/kg up to) 330 mg orally, daily for minimum of 3 weeks.

 

Clinical improvement usually occurs promptly, but premature cessation of treatment will result in relapse. .

 

Birthmarks

 

Melanocytic naevi (pigmented birthmarks)

One child in 100 is born with a congenital pigmented naevus. Usually these lesions are small (<2cm), but rarely they may be large (20cm or more in diameter). Nearly all children will develop melanocytic naevi after the age of 2 years. Most of these lesions are completely harmless and do not require treatment. All naevi may occasionally become itchy or swollen. In some cases, a white halo may appear around the naevus (halo naevus). All these changes are benign.

The risk of melanoma in childhood naevi is negligible. Melanoma in children is very rare. In large congenital naevi, melanoma may occur before puberty, but not always in the naevus itself, see below.

Surgical removal of cosmetically distressing lesions should be contemplated before the child starts school.

Giant melanocytic naevi

These rare lesions occur in 1 in 500 000 births. They are arbitrarily described as being 20cm or more in diameter. They are invariably present at birth as raised verrucose or lobulated plaques with variable colours, most often brown or black, but slate grey and pink components may occur. The margin may be irregular and there are often long hairs protruding from the lesion. With time they often become thicker and hairier, although the overall size remains stable relative to the patient’s growth. They may be seen in a garment distribution on the trunk and may be surrounded by numerous satellite lesions.

The risk of melanoma in such large lesions is controversial and is probably from 4 to 6% over a lifetime. Of importance is the fact that melanoma may occur before the age of 10. This is extremely rare in small congenital naevi. Naevi involving the posterior trunk are most at risk, and large numbers of satellite lesions also correlate with melanoma risk. Lesions of the scalp and over the spine may also be associated with neurocutaneous melanosis (infiltration of the central nervous system by melanocytes or melanoma).

In some children with giant naevi, magnetic resonance imaging (MRI) appearances of the brain are abnormal, but the exact significance of this is unknown and for the time being MRI is not recommended unless there are neurological signs. In at least half the cases of melanoma occurring in patients with giant melanocytic naevi, the malignancy is found in areas other than the naevus.

Removal of such large lesions is rarely easy and may involve numerous complex surgical procedures. Further, since melanoma may be extralesional, surgical removal may not necessarily decrease the risk of melanoma. Curettage in the neonatal period has been recently described as a treatment modality for these lesions. They may also be treated with dermabrasion and laser therapy. These are cosmetic procedures that still leave a cancer risk and the cosmetic effect may not be lasting. Referral to a dermatologist is recommended for any newborn with such a lesion.

Capillary haemangioma

This is a common tumour of infancy affecting 10% of neonates. It is more common in girls and in premature babies. Although not usually present at birth, the lesion appears within the first month of life and then expands for up to 20 weeks, rarely reaching very large proportions. After stabilising, the lesion then slowly regresses, resolving substantially by the time the child is of school age and completely by the age of 9 years.

The majority of these lesions do not cause a problem and, because of their natural history, no treatment is recommended. However, for facial lesions that may become disfiguring, lesions interfering with an orifice (eye, ear, nose, genitals) or rapidly growing large lesions, recommended therapy is

prednisolone 2 to 4mg/kg orally, daily.

 

Therapy should be started as early as possible and urgent referral to a paediatrician or dermatologist is recommended.

Capillary malformation

This lesion, encountered in 1 in 1000 births, is present at birth although not always obvious, and may not be diagnosed for several months. This is a malformation and is a permanent lesion. It may be associated with underlying vascular and soft tissue abnormalities. When found on the face in the distribution of the first trigeminal nerve, particularly when there is upper eyelid involvement, the Sturge-Weber syndrome may be associated, with epilepsy and ocular abnormalities. Referral to a paediatrician is recommended.

Capillary malformations may be treated by laser, and this is best done before the child enters school. Extensive lesions should be investigated by ultrasound to determine if there are underlying abnormalities. Lesions on the face may require computerised tomography scan investigation and ophthalmology referral.

 

 

 

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