This disorder is characterized by crops of large, tense, non-inflammatory bullae that appear spontaneously in patients with diabetes. Lesions are usually asymptomic and are most commonly located on the feet and lower legs. Bullae typically rupture after being present for approximately one week and leave deep, painless ulcers that may take many weeks to heal, even if not infected. There is no significant scarring.
The etiology of this disorder is unknown but it is not autoimmune/immunologic in nature. On histopathologic exam, the split typically occurs in a subepidermal location, with the cleavage plane in the basement membrane zone above the basal lamina. Treatment is palliative with leg compression and local wound care.