Cutaneous Reactions to Trimethoprim-Sulfamethoxazole in African Patients with the Acquired Immunodeficiency Syndrome

Trimethoprim-sulfamethoxazole has been shown to be effective treatment for Pneumocystis carinii pneumonia and probably as prophylaxis of such infection. However its use in the US is limited by moderate to severe side effects such as rash fever neutropenia thrombocytopenia and hepatitis. Such side effects are most frequent with high-dose intravenous treatment but have also been reported with low-dose oral prophylactic therapy. Cutaneous eruptions occur in 50%-60% of American patients with the acquired immunodeficiency syndrome (AIDS) treated intravenously and generally develop 1-9 days (median 4) after therapy is initiated. From December 1986-March 1987 patients infected with the human immunodeficiency virus (HIV) treated with trimethoprim-sulfamethoxazole consecutively seen at Mama Yemo Hospital Kinshasa Zaire were enrolled in a study and their cutaneous reactions were evaluated. All patients were examined before treatment was started at least once weekly during treatment and after treatment was completed. 72 patients (42 men and 30 women) were enrolled. Patients received trimethoprim-sulfamethoxazole as therapy for pulmonary infections (43 patients 60%) fever of unknown origin (24 patients 33%) Isospora belli infection (4 patients 6%) and for urinary tract infection (1 patient 1%). 8 patients had a documented opportunistic infection (candida esophagitis [6 patients] or chronic herpes simplex ulceration [2 patients] and 6 had Kaposis sarcoma. Medication was given in dosages of trimethoprim 320-640 mg and sulfamethoxazole 1600-3200 mg daily. The mean duration of oral therapy was 12 days (range 1-35 days). 11 (15%) of the patients had a pruritic papular eruption before treatment was started. During treatment pruritus developed in only 3 (4%) of the 61 patients without a pruritic eruption before therapy. In all 3 patients pruritus was noted on the 1st day of treatment but none developed a rash. 1 of the 11 patients with a previous pruritic eruption reported an increase in pruritus after therapy. In 1 of 72 patients trimethoprim-sulfamethoxazole was discontinued after 1 day because of nausea and vomiting. A similar low frequency of cutaneous reactions was reported in Haitian and black American AIDS patients treated with trimethoprim-sulfamethoxazole. In African Haitian and black American patients infected with HIV the incidence of cutaneous reactions during treatment does not seem to be higher than the incidence seen in white patients with diseases other then AIDS. African and Haitian but not American black AIDS patients generally received lower dosages of trimethoprim-sulfamethoxazole and more oral treatment than American white AIDS patients. The pathophysiologic mechanism causing cutaneous reactions in AIDS patients treated with trimethoprim-sulfamethoxazole remains unknown. The finding that such a reaction seems to occur less frequently among African Haitian and American black AIDS patients than in white AIDS patients suggests a genetic susceptibility for such reaction. (full text)