6th July 2023

Bullous Pemphigoid

The most common autoimmune blistering disorder, typically affecting the elderly. IgG autoantibodies attack the basement membrane (specifically BP180 and BP230 proteins), resulting in subepidermal blistering. Bullous pemphigoid has been associated with:

• Neurological disorders: stroke, Parkinson’s disease, dementia, epilepsy and multiple sclerosis.
• Medications: antibiotics, penicillamine, ACE inhibitors, Beta-blockers, DPP-4 inhibitors (e.g. sitagliptin), diuretics, immune checkpoint inhibitors
• Physical triggers: trauma and burns

The onset of blisters is preceded by a non-bullous phase lasting weeks or months. This presents as intense itching which may be accompanied by erythema and/or urticated plaques. The bullous phase consists of localised or widespread tense bullae on erythematous or normal-looking skin. The trunk and flexor aspect of the limbs are typically affected. Mucosal involvement is uncommon.

Bullous pemphigoid

Image Source: Wikimedia Commons (2018). Drugs induce pemphigoud bullous, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Drugs_induce_pemphigoud_bullous.jpg (Accessed on: 10 March 2022).

Investigation involves checking serum antibodies and skin biopsies for histology and direct immunofluorescence. Histology and immunofluorescence will demonstrate subepidermal blistering and IgG deposition at the basement membrane, respectively. Super-potent topical steroids can treat localised disease, whereas widespread disease will require oral prednisolone +/- immunosuppressants (e.g. Azathioprine). Doxycycline 200 mg daily is an alternative to immunosuppressive therapy, due to its anti-inflammatory properties, and it has fewer side effects compared to oral prednisolone.