Author: Dr Ian Coulson, Consultant Dermatologist and Editor-in-Chief (2025).
Edited by the DermNet content department.
This elderly lady has been experiencing generalised itch for two months and, more recently, has developed lesions on her legs. She has type 2 diabetes mellitus and takes an oral agent to control this.
The image shows erosions along with some intact blisters arising on an erythematous base.
The prodrome of generalised itch followed by a rash and blisters would suggest a likely diagnosis of bullous pemphigoid.
The diagnosis can be confirmed by skin biopsy.
Histological examination of lesional skin will show a subepidermal blister, sometimes accompanied by an eosinophil-rich dermal infiltrate.
Direct immunofluorescence of perilesional skin will show linear IgG and C3 at the dermoepidermal junction.
For more information, see: Bullous pemphigoid pathology.
Gliptins (also known as DPP-4 inhibitors) are a class of antidiabetic medications that have been increasingly implicated in the development of bullous pemphigoid. Ideally, the drug should be discontinued and substituted with a different class of medication.
