Bullosis diabeticorum (BD), also known as bullous eruption of diabetes mellitus or diabetic bullae, occurs in about 0.5% of people with diabetes (type 1, type 2) and has an unknown pathogenesis. The co-occurrence of neuropathy and nephropathy suggests an underlying microangiopathy. Bullae seen in BD are noninflammatory and often develop rapidly. Most people will be asymptomatic or experience mild burning and discomfort. However, those with large bullae on the feet (particularly in older adults) may become unable to wear shoes, leading to a significant reduction in mobility and autonomy.

BD often develops in long-standing, uncontrolled diabetes, although there are reports of BD as the presenting sign of diabetes. Disabling BD has also been reported in older adult patients with optimal glycemic control. Bullae often resolve on their own without scarring, but recurrence is common, and new bullae can continue to form over a period of years. The average age of onset is 55 years, and there is a 2:1 male-to-female ratio.