Topical rapamycin for acanthosis nigricans in the Fitzpatrick IV/V adolescent population.

Dermatologically, FGFR3 mutations can lead to acanthosis nigricans (AN), epidermal nevi, and seborrheic keratosis. A recent case report found that topical rapamycin (sirolimus) can improve FGFR3-induced epidermal nevi with AN features in children, specifically with Fitzpatrick skin type (FST) I/II, and we would like to expand these findings to skin plaques with extensive AN-like features in the FST IV/V adolescent population. An 18-year-old female with FST IV/V and FGFR3-induced hypochondroplasia presented to our clinic with extensive AN-like plaques. Significant improvement with lightening and thinning of the plaques was observed after applying 1% topical rapamycin cream twice daily. Topical rapamycin should be considered as a treatment option for AN, particularly in FST IV/V adolescents with FGFR3-induced AN.