March 2018 | Case of the month

The diagnosis is bullous pemphigoid. Indeed the patient had other tense blisters at other body sites.

• Bullous pemphigoid commonly starts with itching and fixed urticarial-like lesions or occasionally an eczematous rash, which predominantly affects the limbs
  • The itch may precede the rash for several months
  • An urticarial prodrome usually lasts 1-3 weeks before the blisters arise, whereas an eczematous prodrome may precede the blisters by several months 
     
• Distribution of blisters
  • Generalised bullous pemphigoid is the most common form, blisters can form anywhere and are especially widespread on the trunk, proximal limbs and flexures. Once blisters arise they can become widespread within a matter of days 
  • Localised bullous pemphigoid is less common, and is usually limited to the lower extremities. Occasionally this may progress to generalised disease   
     
• Morphology of blisters 
  • Crops of large, tense, fluid-filled blisters, which may arise from normal-looking or erythematous skin
  • They are generally clear but can be cloudy or blood-stained 
  • Blisters may remain intact for several days 
  • Lesions heal quickly and without scarring
  • Post-inflammatory hyperpigmentation and / or milia may follow, but these usually resolve within a few months 

If bullous pemphigoid is suspected in the pre-blistering phase it can be helpful to do a blood test for skin antibodies (pemphigoid and pemphigus), which will be positive in some patients with bullous pemphigoid.

Please refer to the chapter on blistering disorders for further information on bullous pemphigoid and other bullous disorders.