Multiple lentigines arising in resolving psoriatic plaques after treatment with etanercept.

Development of lentigines in zones previously affected by plaques of psoriasis has been described, and its frequency has probably been underestimated. Most cases have been described following the use of phototherapy, although other authors have observed the appearance of lentigines in patients with psoriasis treated only with topical products. It has been suggested that the mechanism involved could be an abnormal reaction to UV light or an unusual form of postinflammatory hyperpigmentation. We report the case of two patients in whom multiple lentigines appeared, confined to plaques of psoriasis after using etanercept. Development of lentigines after using biologic drugs is a phenomenon that does not appear to have been described previously. We consider that the mechanism of production of lentigines is related to psoriasis itself and not to the therapy used.