Paediatrics: Miscellaneous skin conditions

Miscellaneous skin conditions

Ichthyoses

Inherited group of disorders with underlying abnormal keratinization. The most common variants include:

•   ichthyosis vulgaris;

•   x-linked recessive ichthyosis;

•   lamellar ichthyosis (LI);

•   non-bullous congenital ichthyosiform erythroderma (CIE);

•   bullous congenital ichthyosiform erythroderma.

Some types present as a ‘collodion’ baby (LI and CIE most commonly). There may also be eye ectropion and lip eclabium. Otherwise, presents in the first few months of life with dry scaly skin +/– erythema.

Investigation 

Skin biopsy and histology.

Treatment

Avoid soap and detergents, use bath oils, apply regular urea-containing emollients, or mild keratolytics (e.g. 1% salicylic acid in aqueous cream). If severe, oral retinoids are justified.

Prognosis 

Most forms improve with age (except X-linked ichthyosis).

Dermatitis herpetiformis

•   A rare, chronic autoimmune disease s to IgA antibody directed against dermoepidermal junctional antigen.

•   Occurs in coeliac disease. Affects ages 6–12yrs.

•   Presents as an initial itchy rash of knees, elbows, buttocks, perineum that evolves into blisters.

Treatment 

Gluten-free diet; oral dapsone. Prognosis is good.

Epidermolysis bullosa

A group of genetically distinct disorders in which the epidermis separates from dermis. Often presents at birth with sloughing of skin (9 mucous membranes) following minor skin trauma; blister or bulla formation; exhibits positive Nikolsky’s sign. The level of epidermal/dermal cleavage differs between disorders with the more severe form resulting in scar-ring, finger pseudowebbing, oesophageal strictures, and limb contractions. Nails, hair, teeth may also be affected. Skin biopsy for immunofluorescent mapping determines precise diagnosis.

Treatment

Supportive (e.g. minimal handling, skilled nursing on silk sheets, foam padding, IV fl uid/protein/electrolyte replacement as needed, antibiotics for superficial infection, nutritional support, topical paraffin and non-adherent bandaging of blistering areas). Referral to specialized unit is recommended.

Prognosis

Variable and depends on exact disorder. Generally, autosomal recessive forms are more severe, result in scarring, and present at birth. Severe forms are frequently lethal in newborn period. Prognosis improves with skilled input.

‘Adult’ seborrhoeic eczema

Affects post-pubertal child. Caused by yeast overgrowth, e.g. Malassezia ovale. Presents with erythema with overlying scaling affecting scalp (dan-druff), eyebrows, nasolabial folds, cheeks, and joint flexures. Treat with a mild topical steroid/antifungal.

Zinc deficiency

Causes

Dietary deficiency (e.g. breastfed very preterm infants) and acrodermatitis enteropathica (rare autosomal recessive defect in zinc absorption).

Presentation

Infants develop demarcated areas of erythema, scaling, and pustules around the mouth, ears, fingers, and toes, anogenital regions; diarrhoea; FTT.

Investigation 

Low plasma zinc levels.

Treatment 

Oral zinc supplements restore health.

Ectodermal dysplasia

There are many forms, the commonest is hypohidrotic ectodermal dyspla-sia (X-linked recessive).

Presentation

Sparse sweat glands, dry skin, sparse hair, thin eyebrows, characteristic facies (prominent frontal ridges in chin, saddle nose, sunken cheeks, thick lips, large ears), and defective peg-shaped teeth. Patients are prone to hyperthermia and heat stroke due to reduced/absent sweating.

Treatment 

Supportive. Avoid hyperthermia and treat appropriately if it occurs with rehydration and salt replacement. Use dental prosthetics.

Incontinentia pigmenti

In this rare X-linked dominant ectodermal dysplasia girls present in the neonatal period with blistering lesions (cropping circumferentially on the trunk and in a linear distribution on the limbs) that within weeks turn into warty plaques and nodules that resolve to leave streaky hyperpigmenta-tion. Ultimately, the lesions regress by late childhood to leave atrophic, streaky areas of hypopigmentation (often most noticeable on the back of the calves). Associated with dental, eye, musculoskeletal, and neurological abnormalities. No specific treatment available.

Dermatitis artefacta

Caused by self-inflicted skin lesions. Usually affects adolescent girls. Lesions are very variable, but are usually bizarre and sudden in appearance. A help-ful clue is that the patient is often inappropriately unconcerned. Occlusive dressing leads to rapid healing. Sympathetic listening is most likely to be helpful. Consider underlying abuse. Psychiatric input may be helpful.

Lichen planus

Cause is unknown. Itchy, flat-topped violaceous papules develop, usual-ly over flexor aspects of wrist and trunk. Papules tend to coalesce into hypertrophic plaque. The nails (pits or ridges) and mouth (white lacy net-work) are also often involved.

Treatment 

Topical steroids. Lesions may recur for several years.

Mastocytosis

In this developmental, abnormal collection of skin mast cells, single or multiple macular or nodular lesions urticate when rubbed (Darier’s sign). Hyperpigmentation develops after several months. There may be systemic involvement.

Treatment 

Antihistamines. Lesions and pigmentation resolve.