Paediatric Dermatology and Genodermatoses
Neonatal and infant skin
Erythema toxicum (blotchy erythema with eosinophil-rich pustules, day 2–3, self-limiting), miliaria (sweat duct obstruction) and neonatal cephalic pustulosis are benign - recognise them so antibiotics are avoided. Nappy rash: irritant dermatitis spares the flexures, whereas candidal dermatitis involves flexures with satellite pustules; seborrhoeic dermatitis is a third pattern.
Inherited disorders
Neurofibromatosis type 1: six or more café-au-lait macules over 5 mm (prepubertal), axillary or inguinal freckling, neurofibromas, Lisch nodules, optic glioma. Tuberous sclerosis: ash-leaf macules, facial angiofibromas, shagreen patch, seizures. Sturge–Weber: facial port-wine stain in the V1 distribution with neurological and ocular risk. Ichthyosis and epidermolysis bullosa need multidisciplinary care.
Vascular anomalies
Infantile haemangioma appears after birth, proliferates, then involutes; oral propranolol is indicated for problematic lesions (ulceration, visual axis, airway, large segmental). Segmental facial haemangioma should prompt consideration of PHACE syndrome. Port-wine stains do not fade and respond to pulsed dye laser.
Common paediatric dermatoses
Atopic dermatitis, molluscum contagiosum, viral warts, tinea capitis, hand-foot-and-mouth disease and drug eruptions are frequent. Mastocytosis shows a positive Darier sign on rubbing.
Traps
- Missing a segmental haemangioma syndrome.
- Treating tinea capitis with topical therapy alone.
- Attributing blistering in a newborn to infection when a genodermatosis is possible.
- Overlooking safeguarding when lesions do not fit the history.
Rule of thumb
In a child, a "birthmark" plus one syndrome feature means look carefully for a second and third before reassuring the family.