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In conjunction with BMJ Case Reports, DTB will feature occasional drug-related cases that are likely to be of interest to readers. These will include cases that involve recently marketed drugs for which there is limited knowledge of adverse effects and cases that highlight unusual reactions to drugs that have been marketed for several years.
Summary
We describe two patients, in their 70s, each presenting to the emergency department, with 6-week histories of progressively developing pruritic bullae. Both individuals had multiple comorbidities, including type 2 diabetes—for which they took linagliptin, chronic kidney disease, hypertension and prosthetic heart valves. Owing to systemic illness and endocarditis secondary to superadded bacterial infections, they both required intensive treatment and prolonged hospital admissions.
Despite the beneficial effect of linagliptin on glycaemic control and its reported cardiovascular and renal safety profiles, we add our cases as evidence of the significant risk of developing bullous pemphigoid while taking this medication. Secondary infection of bullous pemphigoid increased the risk of developing endocarditis, particularly among individuals with a medical history of valve replacement surgery. Considering this, we advocate caution when prescribing this medication.
Background
Bullous pemphigoid (BP) is an autoimmune blistering disease, more common in the elderly, characterised by tissue bound and circulating autoantibodies to the epidermal basement membrane. These are predominantly directed to two components of the hemidesmosomes, BP180 and BP230.1 Although diagnosis is clinical, it can be confirmed by a mixture of histopathology, circulating autoantibodies and direct immunofluorescence.2 Most cases are idiopathic; however, certain medications, have been linked to the disease.
Dipeptidyl peptidase (DPP)-4 inhibitors are oral hypoglycaemic agents that treat type 2 diabetes via inhibition of glucagon-like peptide 1 breakdown.3 This results in increased insulin secretion, decreased glucagon secretion and delayed gastric emptying.4 Linagliptin has been a preferred agent in this class as dose adjustment …
Footnotes
Contributors The following authors were responsible for drafting of the text, sourcing and editing of clinical images, investigation results, drawing original diagrams and algorithms, and critical revision for important intellectual content: supervised by AC. Patients were under the care of AC. Report was written by MPV, AT and AC. The following authors gave final approval of the manuscript: MPV, AT and AC.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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