Bloody blisters

There are a couple of firm intact blisters, a partially ruptured blister and some older blisters with blood in them and an eroded base. The blood and the firm overlying epidermal wall suggests that the split is deep in the epidermis, perhaps at the dermo epidermal junction. This makes a blistering staph impetigo very unlikely as it causes the split in the high subcorneal skin level well away from any underlying blood vessels. This is bullous pemphigoid, the commonest autoimmune blistering disease in the elderly. The other two blistering conditions associate with blood in the blisters are porphyria cutanea tarda on sun exposed areas and epidermolysis bullosa acquisita (EBA). For images and treatment, log into