This 16-year-old boy with obesity (BMI 40), insulin resistance, and gynecomastia presented with a 6-mo hx of thickened, hyperpigmented, scaly reticulate eruption on the chest, back, and abdomen. A scraping for fungus was negative. What is the diagnosis?
Terra firma-forme dermatosis
Scabies infestation
Papillomatosis (CARP) + acanthosis nigricans
Pityriasis (tinea) versicolor
Tinea corporis (ringworm)
You are correct. Acanthosis nigricans and confluent and reticulated papillomatosis (CARP). After 2 months of minocycline, the rash improved, but hyperpigmentation persisted in the neck, midchest and axillae, consistent with acanthosis nigricans.