Pediatric Dermatology and Genodermatoses
Pediatric dermatology
Neonatal skin has immature barrier function, higher surface-area-to-weight ratio (affecting topical drug absorption), and distinct eruption patterns. Know transient neonatal eruptions (erythema toxicum neonatorum, milia, sebaceous hyperplasia, neonatal cephalic pustulosis), atopic dermatitis with its age-related distribution, nappy rash vs candidiasis, and vascular anomalies (infantile haemangioma versus vascular malformation).
Genodermatoses
Learn the inheritance and hallmark features of neurofibromatosis type 1 (café-au-lait, freckling, neurofibromas, Lisch nodules), tuberous sclerosis (ash-leaf spots, angiofibromas, shagreen patch), xeroderma pigmentosum (defective nucleotide excision repair, photosensitivity, malignancy), epidermolysis bullosa (structural proteins, mechanobullous), ichthyoses, and incontinentia pigmenti (X-linked dominant, Blaschko lines, male lethality).
Traps
- Infantile haemangioma proliferates then involutes; vascular malformations do not.
- Café-au-lait spots alone are not diagnostic - count and context matter.
- Incontinentia pigmenti is X-linked dominant with male lethality, so affected males are rare.
- Neonatal topical absorption can cause systemic toxicity (e.g., steroids).
Rule of thumb
For a child with a genodermatosis, build a system checklist (skin, eye, nervous system, skeleton, malignancy risk). Exam stems often test the extracutaneous association rather than the skin sign itself.