Abstract: Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is an acute, rare and potentially fatal drug reaction. To date, limited studies have reported secondary Pneumocystis jirovecii pneumonia (PJP) infection during the treatment of DRESS syndrome. A 53-year-old man was admitted to the hospital due to a persistent fever lasting for 5 days. He had a medical history of hypertension, psoriasis, urticaria, and had recently been treated with carbamazepine for nerve spasm two weeks ago. After admission, the patient presented with a high fever accompanied by chills, abdominal pain, bilateral upper limb muscle pain, and generalized lymph nodes enlargement. Laboratory tests revealed elevated eosinophils and atypical lymphocytes. Subsequently, the patient developed multiple internal organ complications, including oliguria, elevated serum creatinine, liver enzymes, and cardiac troponin I. Based on diagnostic criteria, the patient was diagnosed with DRESS syndrome. To manage the DRESS syndrome, the patient was successively or simultaneously prescribed methylprednisolone, cyclosporin and intravenous immunoglobulin, resulting in an improvement of the condition. However, during the treatment, the patient was infected with Pneumocystis jirovecii. Despite targeted therapy with trimethoprim/sulfamethoxazole, primaquine and clindamycin successively, no remission was observed. Chest CT scans exhibited multiple exudations in both lungs, indicative of interstitial pneumonia. Unfortunately, the patient’s oxygenation progressively declined, leading to his untimely demise. This rare case further highlights the need for clinicians to be aware of the risk of Pneumocystis jirovecii infection in DRESS syndrome patients treated with long-term and high-dose glucocorticoid therapy.

Keywords: DRESS syndrome, Pneumocystis jirovecii pneumonia, carbamazepine, glucocorticoid therapy, case report