Pediatric Dermatology and Genodermatoses
Scope
Questions cover neonatal skin lesions, vascular anomalies, inherited ichthyoses, epidermolysis bullosa, and neurocutaneous syndromes, with emphasis on distinguishing benign transient eruptions from serious disease.
Core rules
- Neonatal pustules: erythema toxicum has eosinophils; transient neonatal pustular melanosis has neutrophils and leaves pigmented macules.
- Ichthyoses: ichthyosis vulgaris (FLG), X-linked (STS deletion), Netherton (SPINK5), harlequin (ABCA12).
- Epidermolysis bullosa: simplex (keratin), junctional (BPAG2/laminin-332), dystrophic (collagen VII); dystrophic scarring and esophageal stenosis.
- Neurofibromatosis type 1: café-au-lait macules, axillary freckling, Lisch nodules, neurofibromas; NF1 gene.
- Tuberous sclerosis: ash-leaf spots, facial angiofibromas, seizure disorder; TSC1/TSC2; mTOR inhibitors for subependymal giant cell astrocytoma.
- Incontinentia pigmenti: X-linked dominant, NEMO, Blaschko-linear stages.
- Infantile hemangioma: proliferation then involution; beta-blockers for problematic lesions. Port-wine stains: PDL.
Worked example
An infant has hypopigmented ash-leaf macules and seizures. Reasoning: the combination suggests tuberous sclerosis; Wood's lamp helps detect macules, and MRI is indicated for neurologic symptoms.
Traps
Do not mistake neonatal pustular melanosis for infection. Harlequin ichthyosis is ABCA12-related, not keratin-related. Port-wine stain in a trigeminal distribution warrants evaluation for Sturge-Weber syndrome.