Serum sickness-like illness associated with rifampicin.

We describe a patient with human immunodeficiency virus infection who developed the main clinical features of a serum sickness reaction while receiving treatment with daily therapeutic doses of tuberculostatic drugs. A decrease in complement titers as well as a detection of significant levels of circulating immune complexes were observed. A positive skin test result was observed six hours after an intradermal test with rifampicin. No immunoglobulin or complement deposition was observed by direct immunofluorescence of a punch biopsy specimen from the cutaneous lesion.