Rash Evaluation in a Transplant Patient.

Objective: To present the case of a solid organ transplant recipient with a rash, which might be a drug allergy mimic.

Case report: We present a 62-year-old male lung transplant recipient, who experienced a sudden erythematous rash two months post-transplant after he was given new medications for his transplant status. Physical examination by the team revealed the patient had a generalized flat, polymorphic papular rash with pinpoint crusting and associated excoriations. Skin biopsy indicated purpuric interface dermatitis with eosinophils, which suggested a drug reaction. In the workup process, patient was admitted for Rhinovirus (HRV) infection and placed on 30 mg prednisone tapering. His rash slowly resolved with discontinuation of Bactrim and Voriconazole. His overall clinical picture was concerning for a drug allergy, but he was on high-dose systemic corticosteroid regimen (Prednisone 40 mg daily) which hindered drug allergy testing.

Conclusion: Findings suggest a potential drug allergy or drug reaction, but workup was limited. Thus, the consulting clinician could consider this case a drug allergy mimic or should consider other medical conditions. Challenges exist in identifying a correct differential diagnosis of drug allergy in clinically complicated transplant patients; misdiagnosis may occur, which might lead to delayed care. There is a need for alternative differential diagnostic strategies and treatment options.