Abnormal blistering of the skin 2008-04-02T03:54:00Z true Blistering, generalised UMLS:C2220104 Blister HP:0200038 Blistering, generalized Skin bullae UMLS:C2132198 HP:0007496 A bulla is a large vesicle described as a rounded or irregularly shaped blister containing serous or seropurulent fluid, equal to or greater than 10mm. In approaching blistering diseases, there are 3 fundamental criteria to consider: (1) the site or level of the blister (or the lowest level of vesiculation): subcorneal, midepidermis, suprabasal, subepidermal; (2) the findings that implicate the mechanism of blister formation (spongiosis, acantholysis, blistering degeneration, or epidermolysis); and (3) the type of inflammation (neutrophilic, lymphocytic, eosinophilic, mixed), if present. The presence of one or more bullae on the skin, defined as fluid-filled blisters more than 5 mm in diameter with thin walls. Skin blisters HP:0007467 UMLS:C0241054 HP:0008066 Abnormal blistering of the skin Blisters Abnormal skin morphology