Causes, Diagnosis, and Treatment of Vesicles

A vesicle, also known as a blister or a vesicular lesion, forms when fluid becomes trapped under the epidermis, creating a bubble-like sac. The surrounding skin keeps fluid in place, but the vesicle can break open very easily and release the fluid.

Vesicles are defined as less than one centimeter in diameter, and they can contain fluid or air. They can be signs of chicken pox, early stages of eczema, contact dermatitis, shingles, and herpes simplex.

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A child's neck covered with chicken pox
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Vesicles are triggered by a number of causes. Some are considered minor, like friction. If you've ever broken in a new pair of shoes or used your hands playing sports or doing manual labor, you've probably dealt with blisters. Other minor causes include allergic reactions, contact dermatitis, exposure to chemicals, cold sores, burns, and eczema.

If you have persistent, large legions that multiply or change shape or color, see your healthcare provider. Some causes are serious and require a visit to the practitioner if the vesicles are a result of an existing condition, including:

  • Autoimmune disorders
  • Chickenpox or shingles
  • Herpes
  • Impetigo


A typical vesicle looks like a little bubble of fluid under the skin. The larger the vesicle, the more prone to breaking open, which can be quite painful. It can also cause inflammation in the surrounding area. If a blister bursts prematurely before the underlying skin heals, it poses a greater risk of infection. Blisters that are larger than one centimeter are technically called bullae (bulla is the singular).


Vesicles are easy to recognize since they appear on the surface of the skin. In many cases, your recent health history and/or conditions you have is enough information for a healthcare provider to give a diagnosis on the spot. However, if the cause is uncertain, a practitioner might take a fluid sample or arrange a biopsy of skin tissue.


As tempting as it might be, do not pick or scratch at any lesions. It's important to keep the area clean and the vesicle sealed so the skin beneath can heal. If a vesicle is swollen and painful, a healthcare provider can drain the fluid in a sterile manner, allowing the skin to heal effectively without risking infection.

Vesicle treatment depends on the cause. In many cases, vesicles are treated with over-the-counter medication, or they could heal on their own. Serious cases often come with more serious symptoms, like inflammation or infection, and medication is prescribed accordingly. Vesicles caused by autoimmune disorders can be treated with an antibiotic to combat infection and a corticosteroid to reduce inflammation.


Vesicles aren't always preventable. Those caused by genetics or a viral infection could appear again in the future. Proper care can treat vesicles as they appear, but if they're brought on by a serious condition, they're likely going to return.

If your allergies trigger vesicles, avoid your known allergens, and do not share things like straws, cups and lip care products with others.

Frequently Asked Questions

  • Where do vesicles form?

    Vesicles, also called blisters, can form anywhere on the skin. The most common locations for blisters to form are the hands and feet.

  • Do vesicles itch?

    Yes, a vesicle or blister can be itchy. As tempting as it might be, try not to scratch a blister, since this can cause it to rupture. A ruptured blister is more vulnerable to infection.

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2 Sources
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  1. Cedars-Sinai. Blisters.

  2. Cleveland Clinic. Blisters. Reviewed April 30, 2021.