Dx: Bullous pemphigoid secondary to linagliptin use
DIF of the biopsy sample demonstrated linear deposition of complement 3 (C3) and immunoglobulin (Ig) G along the basement membrane zone. Indirect immunofluorescence on salt-split skin demonstrated linear deposition of IgG and C3 on both the roof and floor of the induced blisters. These findings and the patient’s clinical presentation met the criteria for bullous pemphigoid (BP), which is the most common autoimmune skin-blistering disease.1
BP is associated with subepidermal blistering, which can occur in reaction to a variety of triggers. Pathogenesis of this condition involves IgG anti-basement membrane autoantibody complex formation with the hemidesmosomal antigens BP230 and BP180—a process that activates C3 and the release of proteases that can be destructive to tissue along the dermo-epidermal junction.1
Growing incidence. BP usually occurs in patients > 60 years, with no racial or gender preference.1 The incidence rate of BP ranges from 2.4 to 21.7 new cases per 1 million individuals among various worldwide populations.2 The incidence appears to have increased 1.9- to 4.3-fold over the past 2 decades.2
What you’ll see, who’s at risk
Symptoms of BP include localized areas of erythema or pruritic urticarial plaques that gradually become more extensive. A patient may have pruritis alone for an extended period prior to developing blisters and bullae. The bullae are tense and normally 1 to 7 cm in size.1 Eruption is generalized, mostly affecting the lower abdomen, as well as the flexural parts of the extremities. The palms and soles also can be affected.
FPs should be aware of the atypical clinical variants of BP. In a review by Kridin and Ludwig, variants can be prurigo-like, eczema-like, urticaria-like, dyshidrosiform type, erosive type, and erythema annulare centrifugum–like type.2 At-risk populations, such as elderly patients (> 70 years), whose pruritis manifests with or without bullous formation, should be screened for BP.3,4
Continue to: Risk factors for BP