Hemorrhagic bullous pemphigoid developing after linagliptin

Linagliptin, a dipeptidyl peptidase IV inhibitor used to treat diabetes mellitus, has been associated with increased blood urea levels, increased lipase levels, arthralgia, dermatological reactions, heart failure and hypersensitivity reactions. A 68-year-old female patient presented to the emergency department with pruritic, raised, and hemorrhagic bullous eruptions on the skin. The patient's medical history included diabetes mellitus, hypertension and renal failure, and it was noted that she had started linagliptin therapy three weeks previously. The patient's complete blood count and biochemistry were unremarkable. Physical examination revealed fluid-filled lesions on the neck, back of the neck, trunk and both thighs. Examination of the oral and genital mucosa was normal. The patient had erosive haemorrhagic bullae and the Nikolsky sign was negative. After consultation with the dermatology department, a skin biopsy was planned, and after consultation with the internal medicine department, it was suggested that the current clinical condition was linagliptin-dependent and discontinuation of the medication was recommended. Bullous lesions are often associated with autoimmune etiologies and are observed between two weeks and five months. However, in subepidermal cases, the prognosis of haemorrhagic clinical features is more fatal and morbid compared to non-haemorrhagic ones. Various dermatological symptoms and bullous pemphigus have been reported in the literature following the use of linagliptin, whereas our case was a haemorrhagic bullous pemphigus.