Dapsone-induced methemoglobinemia: an anesthetic risk

Dapsone is used to treat several systemic inflammatory diseases, many of which have head and neck manifestations, such as leprosy, systemic lupus erythematosus, rhinosporidiosis, relapsing polychondritis, dermatitis herpetiformis, pemphigus vulgaris and bullous pemphigoid. It has also been recently used prophylactically alone or in combination against malaria and in AIDS patients against Pneumocystis carinii infections. This is significant to the otolaryngologist-head and neck surgeon since approximately 40% of AIDS patients will have head and neck manifestations. Thus, the likelihood that otolaryngologists will be treating patients who are taking dapsone regularly is significant. We present a case of a 16-year-old female who presented with a presumptive diagnosis of discoid lupus for biopsy confirmation of her disease. Induction of general anesthesia was complicated by methemoglobinemia, an uncommon side effect of dapsone. We will discuss recognition and prevention of this side effect, its potential anesthetic implications, complications and treatment.