Pediatric Dermatology and Genodermatoses
Domain 9 tests benign neonatal findings versus serious genodermatoses, and cutaneous clues to multisystem disease.
Neonatal and infantile
- Transient benign findings: erythema toxicum (eosinophils), transient neonatal pustular melanosis, milia, sebaceous hyperplasia, salmon patch.
- Diaper dermatitis: irritant on convex surfaces versus candidal with beefy redness and satellite pustules.
- Infantile haemangioma proliferates then involutes; propranolol for threatening or ulcerated lesions; more than five lesions warrant liver ultrasound.
Genodermatoses
- Epidermolysis bullosa: cleavage level (simplex, junctional, dystrophic) predicts scarring and extracutaneous disease.
- Ichthyosis: harlequin, lamellar, X-linked steroid sulfatase deficiency with corneal opacities.
- Neurofibromatosis type 1: cafe-au-lait macules, freckling, neurofibromas, Lisch nodules, optic glioma.
- Tuberous sclerosis: ash-leaf spots, facial angiofibromas, Shagreen patch, seizures, renal angiomyolipoma; mTOR inhibitors.
- Incontinentia pigmenti: X-linked dominant, Blaschko lines, four stages.
Worked example
A 2-year-old has eight cafe-au-lait macules, axillary freckling and two cutaneous neurofibromas. Diagnosis: neurofibromatosis type 1, since clinical criteria are met. Reasoning: pigmentary criteria plus neurofibromas suffice; arrange ophthalmology and genetics rather than biopsying every lesion.
Traps
Do not confuse salmon patch with port-wine stain; a V1 port-wine stain needs glaucoma and CNS assessment. Do not delay propranolol for a vision-threatening haemangioma. Do not miss failure to thrive in ichthyosis.