Health Library

Vesicles

Blisters

A vesicle is a small fluid-filled blister on the skin.

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Considerations

A vesicle is small. It may be as tiny as the top of a pin or up to 0.20 inches (in) or 5 millimeters (mm) 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.

Causes

Many diseases and conditions can cause vesicles. Common examples include:

• Allergic reactions to medicines
• Atopic dermatitis (eczema)
• Autoimmune disorders such as bullous pemphigoid or pemphigus
• Blistering skin diseases including porphyria cutanea tarda and dermatitis herpetiformis
• Chickenpox
• Contact dermatitis (such as due to poison ivy)
• Herpes simplex (cold sores, genital herpes)
• Herpes zoster (shingles)
• Bacterial infections
• Fungal infections
• Burns
• Friction
• Treatment with cryotherapy (to treat a wart, for example)

Home Care

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

Contact 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.

Related Information

References

Dinulos JGH. Vesicular and bullous diseases. In: Dinulos JGH, ed. Habif's Clinical Dermatology. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 16.

James WD. Cutaneous signs and diagnosis. In: James WD, ed. Andrews' Diseases of the Skin: Clinical Dermatology. 14th ed. Philadelphia, PA: Elsevier; 2026:chap 2.

Kroshinsky D. Macular, papular, purpuric, vesiculobullous, and pustular diseases. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 406.

Review Date: 6/3/2025  

Reviewed By: Ramin Fathi, MD, FAAD, Director, Phoenix Surgical Dermatology Group, Phoenix, AZ. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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