⚪ Chapter 694: Hypopigmented Lesions

Nelson Textbook of Pediatrics 22nd Edition | Disorders of melanin synthesis, melanoblast migration, and melanocyte destruction: Oculocutaneous albinism (OCA types 1-7), ocular albinism, Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, piebaldism, Waardenburg syndrome, vitiligo (segmental vs generalized), tuberous sclerosis (ash leaf spots), hypomelanosis of Ito.

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📋 30 MCQs — Hypopigmented Lesions (Albinism, Piebaldism, Vitiligo, Syndromes)

📇 High‑Yield Review Cards | Hypopigmentation Syndromes

🩺 Hypopigmented Pattern → Diagnosis

Select a hypopigmentation presentation to learn diagnosis, associated features, and management.

📋 Stepwise Evaluation of Hypopigmented Lesions

🔑 Key Principles — Nelson Chapter 694
• Oculocutaneous albinism (OCA): Tyrosinase deficiency. Nystagmus, photophobia, foveal hypoplasia, reduced vision. Skin cancer risk. OCA1A (tyrosinase-negative) → white hair/pink skin. OCA2 most common worldwide.
• Hermansky-Pudlak syndrome: OCA + bleeding diathesis (platelet dense granule deficiency) + pulmonary fibrosis + granulomatous colitis. Common in Puerto Rico (HPS1).
• Chediak-Higashi syndrome: OCA + recurrent infections + easy bruising + neurologic dysfunction + hemophagocytic lymphohistiocytosis (HLH). Giant granules in leukocytes.
• Piebaldism: White forelock, depigmented patches (ventral trunk, extremities), islands of hyperpigmentation. KIT mutation. Congenital, stable.
• Waardenburg syndrome: White forelock, dystopia canthorum (WS1), deafness, heterochromia irides. PAX3, MITF, SOX10.
• Vitiligo: Acquired depigmentation (autoimmune). Generalized (symmetric) or segmental. Treat with topical steroids, calcineurin inhibitors, NB-UVB.

    ⚡ Reflex Prompts — Hypopigmented Lesions

    📖 Summary: Hypopigmented Lesions (Nelson 694)