Dapsone-induced photosensitivity: a rare clinical presentation.

Dapsone is an efficient anti-inflammatory and antimycobacterial agent. It is one of the main constituents of multidrug therapy (MDT). It acts by interference with folate metabolism. Dapsone-induced photosensitivity is a rare, non-dose-related adverse effect of the sulfone and can occur in patients with inflammatory skin disorders treated with dapsone. So far, only 12 cases seem to have been reported in the literature. We report a case of dapsone-induced photosensitivity in an Indian patient with leprosy.

Photosensitisation induced by clofazimine in a cat.

A pale ginger cat was treated with clofazimine for feline leprosy. During the course of treatment, photosensitisation by clofazimine led to a dermatological disease resembling actinic dermatitis. The mycobacterial disease was eventually cured with clofazimine and the photosensitisation was managed by regulating sunlight exposure. Upon review of the literature, this appears to be the first documented case of drug-induced photosensitisation in the cat.

Dapsone-induced photodermatitis in a patient with linear IgA dermatosis.

Dapsone (4, 4' diaminodiphenylsulfone) is an efficient antiinflammatory agent. Its therapeutic use may result in a variety of adverse effects. The most frequent unwanted reactions are hemolytic anemia and methemoglobinemia. By oral route dapsone is mainly metabolized to monoacetyldapsone (MADDS) and hydroxylamine dapsone (DDS-NOH). We report a 76-year-old female patient with linear IgA dermatosis who developed a dapsone-induced photosensitivity 8 weeks after initiation of sulfone therapy. She showed a widespread erythematous eruption in UV-exposed skin area. After clearing of skin lesions the photopatch test revealed positive reactions to dapsone, MADDS and DDS-NOH. Dapsone-induced photosensitivity to date has been described only in leprosy patients. We demonstrate for the first time that this adverse reaction is not restricted to leprosy and that dapsone metabolites may also contribute to the mechanism of photosensitivity like the parent sulfone. Dapsone-induced photosensitivity is a rare, not dose-related adverse effect of the sulfone and can also occur in patients with inflammatory skin disorders.

DDS-induced photosensitivity with reference to six case reports.

Photosensitivity as an adverse reaction to DDS was recognized in 6 patients of our hospital during the summer of 1988. The clinical manifestations and also the management of those patients are given in detail. All doctors and health workers involved with leprosy need to be aware of such a problem and to take correct decisions after weighing the risk of photosensitivity against the potential benefit of DDS.

[Dapsone-induced photodermatitis in a patient with leprosy]. / DDS-induzierte Photodermatitis bei einem Lepra-Patienten.

We report on a 60-year-old man suffering from borderline leprosy. He was treated many times with DDS and Clofazimin and underwent the so-called multiple drug treatment (MDT). Under this therapy, the patient developed allergic photodermatitis. Unfortunately his file was lost and, as nobody was informed about his allergic reaction, he was again treated with the preparations mentioned above. Consequently, he responded once more with photodermatitis.