In dermatology, vesicles and bulla – colloquially called “vesicles and blister” – (vesica, “vesicle,” pl. vesicae; bulla, “blister,” pl. bullae; ICD-10 R21: skin rash and other nonspecific skin eruptions) refer to vesicle-like changes on skin or mucosa. The vesicles are filled with clear or bloody fluid (if they are filled with pus, they are called pustules).
Depending on the diameter, they are referred to as:
- <5 mm: Vesicles (“vesicles”; pl.: vesiculae).
- > 5 mm: Bulla (“bubbles”; pl.: bullae).
The vesicles and bulla belong to the so-called primary florescences. These are skin changes that are the direct result of a disease.
Many different skin diseases such as herpes simplex or allergic reactions can be accompanied by vesicles (vesicula or bulla).
Vesicles and bulla can be symptoms of many diseases (see under “Differential diagnoses”).
Course and prognosis: Course and prognosis depend on the cause. If the underlying disease is treated successfully, the vesicles also disappear.
