What do bullous pemphigoid blisters look like?

Bullous pemphigoid blisters are large and fluid-filled, according to Mayo Clinic. The fluid is usually clear, but it may also have streaks of blood. The blisters are hard to break, and the skin around them can be red or look normal.

Bullous pemphigoid blisters usually erupt on the patient's lower abdomen, upper thighs, groin area or arms, explains Mayo Clinic. They also appear in the mouth and on creases in the skin. Although it's rare, the blisters can appear in the eyes as well.

Bullous pemphigoid blisters usually afflict older people and develop when the immune system attacks the lower layers of the skin, notes Mayo Clinic. Medical experts are unsure of the root cause.