Afebrile vancomycin-induced delayed hypersensitivity suggestive of incomplete drug rash with eosinophilia and systemic symptoms syndrome: a case report.

Background: Vancomycin-induced delayed hypersensitivity reactions are rare and typically accompanied by systemic symptoms such as fever, eosinophilia, and organ dysfunction, known as drug reaction with eosinophilia and systemic symptoms syndrome. However, nonsteroidal anti-inflammatory drugs can mask typical systemic signs, complicating diagnosis.

Case Presentation: A 61-year-old Asian Taiwanese male patient developed widespread erythematous macules and papules, significant skin desquamation, pruritus, and eosinophilia after 25 days of vancomycin therapy initiated for suspected methicillin-resistant Staphylococcus aureus (MRSA)-related spondylodiscitis. Notably, the patient remained afebrile, likely owing to concurrent prolonged aceclofenac (nonsteroidal anti-inflammatory drug) usage, which masked the fever commonly associated with hypersensitivity reactions. Symptoms improved significantly after discontinuing vancomycin and initiating antihistamines and corticosteroid therapy.

Conclusion: This case highlights an atypical presentation of vancomycin-induced delayed hypersensitivity with incomplete drug reaction with eosinophilia and systemic symptoms syndrome due to the absence of fever, potentially masked by nonsteroidal anti-inflammatory drug treatment. Clinicians should remain vigilant for atypical presentations of drug hypersensitivity reactions, especially in patients concurrently taking nonsteroidal anti-inflammatory drugs that can suppress fever.