A case of exogenous ochronosis associated with hydroxychloroquine

Abstract

Exogenous ochronosis is characterized by hyperpigmented skin lesions that arise in association withlocal suppression of homogentisic acid oxidase enzyme. Although it generally develops in associationwith topical application of chemical agents, it can occasionally develop in association with antimalarialdrugs. Here we present the case of a patient with rheumatoid arthritis who developed hyperpigmenta-tion on the face and neck regions during hydroxychloroquine treatment. Hydroxychloroquine is beingwidely used in rheumatology practice, and cutaneous hyperpigmentation may develop as an adverseeffect. In the present case, we emphasize the potential underlying mechanisms through which it maycause cutaneous hyperpigmentation and determine the clinical and histopathological findings of ex-ogenous ochronosis.