Some causes of leg blisters are shingles, scabies, bedbugs and impetigo, says WebMD. Another cause of blistering on the legs is bullous pemphigoid, according to Healthline.
Bullous pemphigoid, an autoimmune disorder, causes rashes and blisters to form on the arms and legs, according to Healthline. This disorder causes the body to attack the skin for unknown reasons, causing fluid-filled sacs to form. Light exposure and specific medications can cause flare-ups, and the disorder can develop in any age group, although the elderly are particularly prone to the disease. Before blisters form on the legs, a red rash forms that can be painful and itchy. When blisters develop, the skin thickens around them and the fluid can contain blood.
Although there is no cure for bullous pemphigoid, treatments include topical medications and corticosteroids for itch relief, antibiotics to prevent infection and immunosuppressants to prevent flare-ups, states Healthline.
Shingles is a viral infection that causes blisters to form throughout the body, even on the legs, explains WebMD. These blisters are caused by the chickenpox virus. Shingles flare-ups begin as a strip of reddened skin that develops into a rash and blisters. The blisters eventually scab over during a course of a few weeks and then disappear.