A Life-Threatening Adverse Reaction During Trimethoprim-Sulfamethoxazole Desensitization in a Previously Hypersensitive Patient Infected with Human Immunodeficiency Virus

Abstract

A Life-Threatening Adverse Reaction During Trimethoprim-Sulfamethoxazole Desensitization in a Previously Hypersensitive Patient Infected with Human Immunodeficiency VirusThe use oftrimethoprim-sulfamethoxazole (TMP-SMZ) in HIVinfected patients is limited by the high frequency of adverse cutaneous reactions.Management of these reactions includes treatment throughout the duration of hypersensitivity, rechallenge, and desensitization.According to published studies, the desensitization procedure is safe [1][2][3][4][5][6].We observed a life-threatening adverse reaction during TMP-SMZ desensitization.A 48-year-old man with asymptomatic HIV infection was enrolled in a 3-day TMP-SMZ desensitization procedure in April 1995.In January 1995 he had experienced a febrile rash 10 days after he began primary prophylaxis with TMP-SMZ (1 doublestrength tablet per day) for pneumocystosis; at that time his CD4+ cell count was 0.199 X 109/L.He also reported a posterior myocardial infarction in September 1994.He was receiving therapy with aspirin (250 mg every other day), didanosine (400 mg/d), and zidovudine (500 mg/d).When he was hospitalized for the desensitization procedure, his CD4+ cell count was 0.366 X 10 9 /L (16% of total lymphocytes).The procedure consisted of incremental administration of TMP-SMZ; on day 1, he received 0.8 mg of TMP and 4 mg of SMZ (9 A.M.), followed by 1.6 mg of TMP and 8 mg of SMZ (11 A.M.), followed by 4 mg ofTMP and 20 mg ofSMZ (1 P.M.), and, finally, 8 mg of TMP and 40 mg of SMZ (5 P.M.).He was receiving therapy with dexchlorphenirarnine at the time (2 mg/d).He did not have a reaction to the three initial doses, apart from mild and transient conjunctivitis after the third dose.Twenty minutes after the fourth dose, he developed tachycardia, bilateral conjunctivitis, high fever, diffuse cutaneous rash, and intense pruritus.