Bullous pemphigoid is an autoimmune blistering disease in which antibodies attack the junction between the epidermis and the dermis. It mostly affects adults over 70 and can be triggered by some medicines, such as DPP-4 inhibitors used for diabetes.
Key symptoms
- Intense itch, sometimes for weeks before blisters appear
- Large, tense, fluid-filled blisters
- Red, hive-like patches on the trunk, arms and legs
- Raw areas where blisters have broken; the mouth is usually spared
What you find on exam
- Tense blisters on normal or red skin, often in skin folds, inner thighs and lower abdomen
- Negative Nikolsky sign: rubbing the skin does not make it slide off
- Erosions and crusts; check for secondary infection
- Mouth involvement is uncommon, unlike pemphigus vulgaris
Tests
- Punch biopsy of a fresh blister for routine histology
- Biopsy of skin next to a blister for direct immunofluorescence: linear IgG and C3 at the basement membrane
- Blood test for BP180 and BP230 antibodies
- Medication review for possible trigger drugs
Treatment basics
- Potent topical corticosteroid such as clobetasol over the affected skin
- Oral prednisone for widespread disease, with a slow taper
- Steroid-sparing options: doxycycline, methotrexate, mycophenolate or dupilumab
- Wound care for erosions; leave blister roofs in place and drain large blisters with a sterile needle
- Stop a likely trigger drug; protect bones and monitor glucose during steroid therapy
Red flags
- Signs of infection or sepsis from open skin
- Mouth or eye involvement, or skin peeling with a positive Nikolsky sign (consider other diseases)
- Frail patient unable to eat, drink or care for the skin
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.