Terbinafine-Induced DRESS Mimicking Acute Cholecystitis: A Rare Presentation

Terbinafine is an antifungal commonly used to treat onychomycosis. Its association with Drug Reaction with Eosinophilia and Systemic symptoms (DRESS) is exceedingly rare with two prior cases reported in the literature. We report a case of terbinafine-induced DRESS who presents with abdominal pain and is initially thought to have cholecystitis. A 66 year old male with a past medical history of hypertension, dyslipidemia and trigeminal neuralgia presents with a three day history of right upper quadrant crampy abdominal pain associated with nausea, asthenia, and low grade fevers. Starting that morning the patient also noticed a rash appearing over his entire body. A CT Abdomen was performed in the emergency room which revealed an edematous gallbladder wall with possible pericholecystic fluid. The patient was thrombocytopenic and had elevated liver enzymes in a mixed hepatic and cholestatic pattern (Table 1) but initial labs were otherwise unremarkable. Lab results a few months prior were within normal limits. The patient was evaluated by surgery and a cholecystectomy was planned for the next day. A few hours later the patient was reassessed due to rapid spread of his rash up to his face, facial swelling and discomfort in the patient's throat. He was given IV epinephrine and diphenhydramine and transferred to our hospital for further care. Upon evaluation, patient was found to have a generalized morbilliform rash covering his entire torso. The patient reported he had been started on terbinafine two weeks ago for toenail onychomycosis. He has otherwise been on his other medications for years. An abdominal ultrasound revealed concentric gallbladder wall edema with no calculi or biliary ductal dilatation. A HIDA scan with CCK revealed mildly reduced gallbladder ejection fraction at 28%. An MRCP was unremarkable. Viral serologies and autoimmune tests were performed and were found to be negative (Table 1).Terbinafine was discontinued and the patient was started on intravenous steroids and his rash, abdominal pain, thrombocytopenia and liver function tests improved over the course of the next few days. The patient was discharged with a steroid taper and close follow up. Terbinafine can be associated with significant hypersensitivity reactions and patients can present with abdominal pain and liver dysfunction. The presence of eosinophilia in DRESS is only found in 30% to 57% of patients and clinicians should be aware of this potentially fatal syndrome.1. Laboratory Results