Longitudinal melanonychia associated with hydroxyurea therapy in a patient with essential thrombocytosis

Occurrence of skin lesions during long-term therapy with hydroxyurea are well described, but there have been only a few case reports of longitudinal melanonychia associated with hydroxyurea treatment. We report herein longitudinal melanonychia associated with hydroxyurea therapy in a subject with essential thrombocytosis. The prolonged time lapse (1 year) between initiation of hydroxyurea therapy and the onset of the longitudinal melanonychia should be noted.