Diltiazem-associated photodistributed hyperpigmentation - A review of 4 cases

Background: Diltiazem hydrochloride is a widely used calcium channel blocki ng agent. While a few cases of diltiazem-associated photosensitivity have b een reported, no cases of photodistributed hyperpigmentation are known. Observation: Four cases of photodistributed hyperpigmentation associated wi th the long-acting formulation of diltiazem hydrochloride (Cardizem CD) are presented. All patients were African American women, with a mean age of 62 years. The mean duration of diltiazem administration prior to the developm ent of hyperpigmentation was 8 months. The hyperpigmentation was slate-gray and reticulated. Phototesting during diltiazem therapy revealed a decrease d minimal erythema dose to UV-A in 1 patient. Histopathologic examination s howed lichenoid dermatitis with prominent pigmentary incontinence. Electron microscopic examination of the tissue revealed multiple melanosome complex es. Discontinuation of diltiazem therapy resulted in the gradual resolution of the hyperpigmentation. Conclusions: Long-term administration of diltiazem may be associated with c haracteristic reticulated, slate-gray hyperpigmentation on sun-exposed area s. Discontinuation of the therapy results in resolution of the eruption.