What is the term for a large blister containing a watery fluid, similar to a vesicle but larger?

A large blister containing a watery fluid is referred to as a bulla. This term is used in dermatology to describe a raised area of skin that is filled with clear fluid and measures more than 0.5 centimeters in diameter. Bulla are distinct from vesicles, which are smaller blisters measuring less than 0.5 centimeters.

The size difference is an important aspect of the classification, as it helps in identifying various skin disorders and conditions. When evaluating skin lesions, understanding these terms is crucial for accurate diagnosis and communication in medical contexts.