Autofluorescence of clofazimine in discoid lupus erythematosus

A 70-year-old woman developed dark reddish blue pigmentation in scarred areas of discoid lupus erythematosus after taking clofazimine intermittently over a period of 10 years. Although light microscopy of routinely processed tissue failed to define the cause of the pigment, fluorescent microscopy showed vivid red deposits concentrated around larger vessels within the dermis. These deposits were shown to correspond to birefringent red clofazimine crystals on fresh frozen sections. Although the hyperpigmentation may clinically resemble melanin, biopsy specimens from our patient revealed a loss of melanin pigment in lesional skin, suggesting a primary role for clofazimine in producing the color changes observed.