Acute generalized exanthematous pustulosis associated with polysensitivityto paracetamol and bromhexine: the diagnostic role of in vitro interferon-gamma release test

We report a patient with acute generalized exanthematous pustulosis (AGEP), which occurred 3 days after ingesting paracetamol and bromhexine. Both wer e immediately stopped and the rash resolved rapidly. To determine the offen ding drug responsible for AGEP, an in vitro drug-induced interferon (IFN)-g amma release test was performed using an ELISA technique. Increased IFN-gam ma release was observed following in vitro challenge of the patient's lymph ocytes with paracetamol or bromhexine (110% and 157% increase, respectively ). In vitro challenge with paracetamol or bromhexine in a control patient, treated with paracetamol and bromhexine, did not induce an increase in IFN- gamma. These findings suggest that the patient with AGEP may have polysensi tivity to both drugs. The ELISA assessment also demonstrates the relevance of in vitro cytokine release tests in the investigation of such dermatoses.