Drug Reaction With Eosinophilia and Systemic Symptoms Secondary to Trimethoprim/Sulfamethoxazole: A Case Report.

Drug reaction with eosinophilia and systemic symptoms (DRESS syndrome) is a rare and potentially life-threatening condition. Symptoms typically manifest two to eight weeks after exposure to an offending agent, such as anticonvulsants and antibiotics. Clinical features include fever, morbilliform rash, eosinophilia, lymphadenopathy, and, in severe cases, multiorgan dysfunction, including interstitial nephritis, hepatitis, and pneumonitis. This case report discusses a 55-year-old female who developed DRESS syndrome while being treated for a urinary tract infection with trimethoprim/sulfamethoxazole (TMP/SMX). Presenting with fever, dysuria, flank pain, and a widespread non-pruritic maculopapular rash, her lab results were remarkable for eosinophilia, while the urinalysis revealed mild hematuria. Computed tomography imaging ruled out nephrolithiasis and acute pyelonephritis, leading to the diagnosis of DRESS syndrome. Management focused on discontinuing TMP/SMX and initiating systemic glucocorticoids. The patient responded well to treatment and was discharged on hospital day two with prescriptions for topical and oral steroids, famotidine, and diphenhydramine. The patient was provided with follow-up instructions and return precautions. Drug reaction with eosinophilia and systemic symptoms poses unique diagnostic challenges due to its similarity to other cutaneous reactions and the delay between drug exposure and symptom onset. Early recognition and intervention are vital for preventing severe complications. Given its potential for multiorgan dysfunction and poor patient outcomes, healthcare providers must be vigilant when evaluating patients presenting with fever and rash. Comprehensive history taking and accurate reconciliation of active and recent medications are necessary to make the diagnosis. Immediate discontinuation of the offending agent is essential, while supportive care and topical or systemic glucocorticoids remain the treatment standards.