A vesicle is a small fluid-filled blister on the skin.
A vesicle is small. It may be as tiny as the top of a pin or up to 5 millimeters wide. A larger blister is called a bulla.
In many cases, vesicles break easily and release their fluid onto the skin. When this fluid dries, yellow crusts may remain on the skin surface.
Many diseases and conditions can cause vesicles. Common examples include:
- Allergic reactions to drugs
- Atopic dermatitis (eczema)
- Autoimmune disorders such as bullous pemphigoid or pemphigus
- Blistering skin diseases including porphyria cutanea tarda and dermatitis herpetiformis
- Chicken pox
- Contact dermatitis (may be caused by poison ivy)
- Herpes simplex (cold sores, genital herpes)
- Herpes zoster (shingles)
- Fungal infections
It is best to have your health care provider examine any skin rashes, including vesicles.
Over-the-counter treatments are available for certain conditions that cause vesicles, including poison ivy and cold sores.
When to Contact a Medical Professional
Call your provider if you have any unexplained blisters on your skin.
What to Expect at Your Office Visit
Your provider will look at your skin. Some vesicles can be diagnosed simply by how they look.
In many cases, additional tests are needed. The fluid inside a blister may be sent to a lab for closer examination. In particularly difficult cases, a skin biopsy may be needed to make or confirm a diagnosis.
Treatment will depend on the cause of the vesicles.
Marks JG, Miller JJ. Vesicles and bullae. In: Marks JG, Miller JJ. Lookingbill and Marks' Principles of Dermatology. 5th ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 10.
Reviewed By: Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.