Melanonychia Caused by Hydroxyurea in Hematologic Patients: Report of 4 Cases

Melanonychia is a nail pigmentation disorder which is predominantly seen in female patients treated by hydroxyurea; especially in patients with diagnosed myeloproliferative disorders. Hydroxyurea inhibits DNA synthesis through its action on ribonucleoside diphosphate-reductase, and can be lead to dermatological disorders including mucocutaneous side effects and nail disorders such as onycholysis, onychodystrophy, and melanonychia. The pathogenesis of hydroxyurea-induced melanonychia is not clear. We present the cases of 4 female patients that two of four patients with diagnosed as polycythaemia rubravera and two of four patients with diagnosed as essential thrombocytosis who are developed melanonychia during hydroxyurea therapy. It is emphasized that the side effects of chemotherapeutic drugs should asses carefully by observing the clinical historyin hematologic patients and treatment should modify, although the side effects will quickly disappear with the reduction or discontinuation of the drug.