Trimethoprim-sulfamethoxazole-induced aseptic meningitis-not just another sulfa allergy

To review the literature on trimethoprim-sulfamethoxazole (TMP-SMX)-induced aseptic meningitis (TSIAM) and discuss the features, possible mechanisms, evaluation, and treatment options relevant for the allergist.

A MEDLINE search was performed using the terms aseptic meningitis, trimethoprim-sulfamethoxazole, trimethoprim, and sulfamethoxazole.

Cases were included that fit the case definition of headache, neck pain, or change in mental status with elevated cerebrospinal fluid white blood cell count or protein attributable to TMP-SMX or either medication alone.

Forty-one patient cases were reviewed. There was a predominance of female patients and patients with autoimmune disease reported. Fever, headache, neck pain, and altered mental status were the most common findings reported in TSIAM reactions. Severe reactions ranged from hypotension to seizure and unconsciousness or coma. Typical cerebrospinal fluid findings included elevated white blood cell count with neutrophil predominance, elevated protein, and normal glucose. Symptoms quickly remitted with withdrawal of TMP-SMX, typically over 48 to 72 hours. Full recovery was typically experienced, although permanent paraplegia was reported in 1 case. The mechanism of reaction is unknown, although an IgE-mediated reaction is unlikely. Many patients experienced multiple TSIAM reactions before the diagnosis was made. Diagnosis can be confirmed with drug challenge or graded test dosing when necessary. Patients with TSIAM subsequently reacted to TMP and SMX alone and therefore should be advised to avoid these 2 classes of medication after diagnosis.

TMP-SMX is the most common antibiotic to cause drug-induced aseptic meningitis. By being aware of this reaction, allergists are well poised to diagnose TSIAM and prevent future reoccurrences for the patient.