Endocrine Abstracts

Introduction: Although dipeptidyl peptidase-4 (DPP-4) inhibitores are generally safe and are associated with less side effects compared to other oral antidiabetic medications, they could also be associated with some side effects including skin rash. Herein we report the first case of a type 2 diabetes patient who developed a painfull maculopapular rash induced by linagliptin, a widely used DPP-4 inhibitor.

Case presentation: A-54-year old female patient with newly diognesed Tip 2 diabetes admitted to our outpatient clinic due to nausea, vomiting, polyuria and polydipsia. Physical examination was normal except for a reduced skin turgor and tonus. On biochemical analysis, her fasting plasma glucose (FPG), HbA1c, white blood cell count (WBC), serum creatinin, BUN and C-reactive protein levels were 300 mg/dL, %9.8, 17.000 (%70 neutrophil), 1.7 mg/dL, 60 mg/dL and 3 mg/L (<5 mg/L), respectively. She didn’t have ketonuria or acidosis and the serum potassium level was normal. One day after starting rehydration with isotonic saline infusion and intensive insulin therapy for acute renal injury and hyperglycemia, the skin turgor and tonus, FPG, serum creatinin, BUN and white blood cells count returned to normal. On the 3th day after admission, treatment with metformin was started, however, she developed dyspeptic complaints and watery diarrhea. Therefore,metformin was stopped and treatment with linagliptin was started. However, one day later, the patient developed a painfull, maculopapular rash without itching, on the palmar sides of the both hands. The linagliptin treatment was stopped. A skin biopsy revealed an eosinophilic superficial dermatitis. So, a diagnosis of an allergic skin reaction due to linagliptin was made.Treatment with bethametasone ointment was started. Four days after cesation of linagliptin and starting treatment with bethametasone oinment, the pain and maculopapular rash were completely dissapeared.

Conclusion: The present case suggests that like other DPP-4 inhibitores such as sitagliptin and vildagliptin, linagliptin may also cause skin reactions. Therefore, attention should be paid to patient receiving this class of drugs and treament should be stopped after appearance of skin reactions. However, it is not well known whether cross reaction would develop after switching to another DPP-4 inhibitor in patients with skin rash developed after starting a DPP-4 inhibitore. However, close follow-up of patients with skin reactions after a DPP-4 inhibitor is necessary to prevent serious skin reactions.