Longitudinal melanonychia and subungual hemorrhage in a patient with systemic lupus erythematosus treated with hydroxychloroquine

Hydroxychloroquine is an antimalarial agent, most commonly prescribed in the treatment of several rheumatic diseases. Although generally well tolerated, a variety of mucocutaneous adverse effects have been reported. Besides the familiar adverse effects, longitudinal melanonychia is rarely seen. Although the incidence is extremely low, systemic lupus erythematosus may also cause nail pigmentation in its own right. We report the case of a 55-year-old woman who was diagnosed with systemic lupus erythematosus and presented with longitudinal melanonychia of all 10 fingernails after 3 years of treatment with hydroxychloroquine, without mucocutaneous hyperpigmentation. The pigment of the nail lasted for more than 15 years. To the best of our knowledge, this is first published report of hydroxychloroquine-induced melanonychia without mucocutaneous hyperpigmentation. This case demonstrates that hydroxychloroquine treatment and the primary disease should be considered in the case of multiple nail changes in patients with systemic lupus erythematosus.