Pediatric and Special Population Dermatology Flashcards

What is the pathognomonic skin finding of Kawasaki disease in children?

Answer: Polymorphous exanthem with desquamation of fingertips in the recovery phase

Kawasaki disease features a polymorphous rash plus desquamation of the fingertips and toes beginning in the periungual region during the subacute phase (10–25 days after fever onset).

Xeroderma pigmentosum (XP) results from defects in which cellular repair mechanism?

Answer: Nucleotide excision repair (NER) of UV-induced DNA damage

XP is caused by inherited mutations in nucleotide excision repair genes, leaving UV-induced pyrimidine dimers unrepaired, leading to early and multiple skin cancers and photosensitivity.

Which congenital melanocytic nevus size poses the greatest risk of malignant melanoma transformation?

Answer: Giant CMN (>20 cm in adult equivalent size)

Giant congenital melanocytic nevi (>20 cm) carry the highest lifetime risk of melanoma transformation (estimated 5–10%) and are also associated with neurocutaneous melanocytosis.

Gianotti-Crosti syndrome (papular acrodermatitis of childhood) is most commonly associated with which viral infection?

Answer: Epstein-Barr virus (EBV)

While historically associated with hepatitis B, Gianotti-Crosti syndrome in the US is now most commonly triggered by EBV infection, presenting with papular eruption on the face and extremities.

What is the recommended treatment for head lice (Pediculosis capitis) when permethrin 1% has failed?

Answer: Oral ivermectin or topical spinosad/benzyl alcohol

Resistance to permethrin is widespread; second-line options include oral ivermectin, topical spinosad (Natroba), or benzyl alcohol (Ulesfia), which work through different mechanisms.

A teenager presents with grouped erythematous papules and nodules along the jawline and perioral area. Which hormonal influence is most implicated?

Answer: Androgens stimulating sebaceous gland activity and sebum production

Teenage acne along the jawline and lower face is driven by androgen-stimulated sebaceous gland hypertrophy and increased sebum production, particularly during puberty.