Confluent and Reticulated Papillomatosis Successfully Treated with Topical Vitamin A Derivative.

Confluent and reticulated papillomatosis (CARP) is a rare dermatosis that typically develops in adolescents and young adults. Clinical characteristics include hyperkeratotic papules that coalesce centrally with a reticulated pattern peripherally on the central and upper trunk, neck, and axilla. Its etiology is not precisely known, and disordered keratinization has been postulated as one of the etiologies. Treatment options of the disease include systemic (such as antibiotics, antifungals, and retinoids) and topical treatments (such as lactic acid, antifungals, retinoids, salicylic acid, urea, tacrolimus, and vitamin D analogs). We report a case of a 17-year-old boy, otherwise healthy, presented with a new onset of asymptomatic, persistent, and slowly progressing brownish skin lesions over the trunk for 6 months. The diagnosis was revised to CARP based on clinical and histopathological examination. Treatment with topical tretinoin 0.025% cream once daily was begun. There was complete resolution of his lesions at the end of 8 weeks of therapy. There has been no relapse at 2 months follow-up. The effectiveness of tretinoin in this patient supports the theory that CARP is a keratinization disorder. Initiating treatment with topical tretinoin when no limitations for its use would be reasonable as it can provide a safer alternative to systemic therapy.