Introduction:
Bullous pemphigoid (BP) is a bullous autoimmune skin disease that is
characterized by autoantibodies targeting BP180 and BP230, which are two
hemidesmosomal proteins localized at the epidermal-dermal junction
[1]. BP is relatively common among elderly people, mainly affecting
the trunk, lower limbs, and face [1]. Various drugs have been
reported to show an association with BP [2]. Recently, there have
been several reports that use of dipeptidyl peptidase-4 (DPP-4)
inhibitors is associated with an increased risk of BP, with the highest
risk being noted for vildagliptin among these drugs [3-6]. DPP-4
inhibitors are oral anti-diabetic drugs that inhibit degradation of
incretins (gastric inhibitory peptide and glucagon-like inhibitory
peptide -1). Several studies have shown that the clinical outcome is
better if DPP-4 inhibitor therapy is discontinued when BP is diagnosed
[7-9].
However, we experienced two cases of BP associated with DPP-4 inhibitor
therapy showing unfavorable outcomes despite immediate discontinuation
of the relevant drugs. Here, we report a total of three cases of DPP-4
inhibitor-associated BP in patients with type 2 diabetes, summarizing
their characteristics and the clinical course of BP after
discontinuation of DPP-4 inhibitors. Patients provided informed consent
for publication of these cases.