A 62-year-old woman was a close contact of a patient with active sputum positive TB. She had a positive Quantiferon test and no evidence for active disease. She had never taken rifampin before. She had hypertension and hyperlipidemia and took metoprolol 25 mg, atorvastatin 20 mg, calcium and vitamin D, and a multivitamin daily. She began rifampin 600 mg daily. Four days later, she developed mild itching that did not respond to diphenhydramine. Twenty-three days later, her lips and eyelid swelled and she developed a generalized rash. She was admitted to the hospital for angioedema. No abnormality was found in routine laboratory tests. She recovered 2 days after stopping rifampin. Her latent tuberculosis was later treated with isoniazid.
In this patient, angioedema developed about a month after starting rifampin and recovered soon after its discontinuance. There was no eosinophilia associated with the reaction. Possible rifampin-associated angioedema was questioned previously, but data have not strongly supported it. The pathogenesis of rifampin-induced angioedema is not clear. It may be a non-immunoglobulin E (IgE) mediated mechanism with an imbalance in the arachidonic acid cascade, increasing of leukotrienes or bradykinin-mediated. We alert readers to this adverse effect of a widely prescribed drug to avoid serious outcomes. Rifampin-induced angioedema is a life threatening side effect; therefore, rifampin should not be readministered.