Bullae is plural for bulla, a fluid-filled sac or lesion that appears when fluid is trapped under a thin layer of your skin. Bullae often heal on their own within a week, but it’s important... Any spherical protrusion, especially a cystic one can be referred to as bulla.

Understanding the Context

A bulla is a fluid-filled sac or bullous lesion that forms when fluid becomes trapped behind a thin layer of skin. It's a blister of some sort. The plural form of bulla is bullae. Bullae are large blisters on the skin.

Key Insights

This guide includes pictures of bullae, as well as information about causes, symptoms, treatments, and more. Vesicles are small blisters less than 5 mm in diameter. A bulla is a larger blister. Note that the plural of bulla is bullae. Blisters may break or the roof of the blister may become detached forming an erosion.

Final Thoughts

Exudation of serous fluid forms crust. Once a blister crosses that threshold, it’s classified as a bulla (plural: bullae). Skin bullae are raised, dome-shaped pockets filled with fluid that sits between layers of skin. They can appear anywhere on the body and vary widely in size, from just over a centimeter to several centimeters across. Bullae are large blisters exceeding 0.5 centimeters in diameter. They appear as raised, fluid-filled sacs on the skin and can be tense or firm to touch.

Unlike smaller blisters, bullae are often associated with underlying skin conditions or systemic health issues. Bullae are large blisters on the skin that are filled with clear fluid. Many different skin conditions can cause bullae to form. They can be caused by infection or inflammation of the skin.