Role of desensitisation for drug hypersensitivity in patients with HIV infection.

Drug hypersensitivity is common in patients with HIV infection and manifests as a delayed onset maculopapular rash, often with fever, mucositis and occasionally visceral involvement. In the 50% of patients who require treatment modification, many can be treated with an equally effective alternative that does not cause hypersensitivity. For the remainder, options include 'treating through' the reaction, adjunctive corticosteroids and/or antihistamines, rechallenge and desensitisation. Formal comparisons are lacking but preliminary data suggest that desensitisation is more successful than rechallenge. The most common reason for performing desensitisation is sulphonamide hypersensitivity for treatment or prophylaxis of pneumocystosis, where success rates of 68 to 100% have been reported. Success seems more likely when regimens lasting 7 or more days are used and in patients with lower CD4+ lymphocyte counts. However, the best tolerated, effective and simple desensitisation regimen has not been determined.