A patient receiving long-term therapy with chloroquine or hydroxychloroquine may develop a hyperpigmentation of the skin and/or nails.
Clinical features:
(1) history of a rheumatic disorder, malaria or other conditions with long-term therapy with chloroquine or hydroxychloroquine
(2) hyperpigmentation of the skin and/or nails which may be bluish, grey or black
(3) exclusion of other diagnoses
(4) reverses if the medication is stopped
(5) hyperpigmentation of the palate or oral mucosa may be present
Pathologic findings in a skin biopsy:
(1) biopsy shows pigment deposition in the dermis
(2) the pigment may stain as hemosiderin or melanin
