Tacrolimus Immunosuppression Causes Drug-Induced Hypersensitivity Reactions In Liver-Transplant Patients: A 3-Case Report

Background. Drug-induced hypersensitivity reactions attributed to the immunosuppressive agent tacrolimus after an organ transplant are rare in the literature. We present 3 cases of male adult patients grafted with a cadaveric liver who developed delayed hypersensitivity reactions to tacrolimus in the form of the prolonged-release capsules (Advagraf). Furthermore, the appropri-ate drug concentration solutions used for allergy testing are proposed. Methods. All patients received a liver transplant (LT) because of cirrhosis of various etiolo-gies. They were immunosuppressed with tacrolimus once daily. Several months after they had been placed on an immunosuppressive regimen with tacrolimus in the form of prolonged-release capsules (Advagraf), the patients presented with delayed hypersensitivity reactions and torturous pruritic rash that affected the whole body and was unresponsive to treatment with oral ursodeox-ycholic acid, cholestyramine, or levocetirizine. Allergy testing that was performed by skin prick testing was negative. Nevertheless, intradermal testing yielded positive results in all 3 patients. Management was by interruption of the culprit agent, which was followed by symptom resolu-tion. The immunosuppressive treatment was continued with alternative drugs. Results. Appropriate nonirritating drug concentration solutions of the drug used for intrader-mal testing were highly sensitive and confirmed the clinical diagnosis of tacrolimus allergy in all the affected patients. Conclusion. Immunosuppressive treatment with tacrolimus in the form of prolonged-release capsules may cause a drug hypersensitivity reaction. A suspicion of allergy warrants a referral for allergy testing. Pruritic rash refractory to treatment in liver transplanted patients should be evaluated by an allergist for possible drug allergy when bile stasis and graft disease have been excluded. Intradermal testing has proven a highly sensitive method for confirming a drug allergy diagnosis, whereas skin prick testing did not.