A vesicle, also known as a blister or a vesicular lesion, forms when fluid becomes trapped under the top layer of skin (epidermis), creating a bubble-like sac.

Skin vesicles can be caused by chickenpox, eczema, rash due to skin irritation or allergy, shingles, friction, bacterial infections, and herpes simplex.

This article explains vesicle symptoms, causes, diagnosis, and treatment.

Vesicle Symptoms

Vesicles appear as small blisters on the skin. They typically look like little bubbles of fluid and are less than one centimeter in diameter. (If a blister is larger than one centimeter, it is called a bulla instead of a vesicle.)

Vesicles can break open very easily. The larger one is, the more prone it is to burst, which can be painful. When this occurs, fluid is released that forms a yellow crust on the skin when dry.

Vesicles can also cause inflammation in the surrounding area. There is a greater risk of infection if a vesicle bursts prematurely before the underlying skin heals.

Vesicular Rash

A vesicular rash is any rash that includes vesicles. Most conditions that cause a vesicular rash are not serious. Some common causes of vesicular rash include:

  • Heat rash. This happens when sweat glands become blocked, trapping sweat under your skin.
  • Contact dermatitis. This can happen when your skin is exposed to an irritant or something you are allergic to, such as chemicals in soap or cosmetics or poison ivy or poison oak.
  • Bacterial infections. Bacterial causes of vesicular rash include erysipelas (St. Anthony’s Fire) and impetigo, an infection that often appears around the nose and mouth.
  • Viral infections. Viruses that are associated with vesicular rashes include herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), which cause blisters around the mouth and genitals. Hand-foot-mouth disease, varicella zoster (chickenpox), herpes zoster (shingles), and syphilis are other examples of viruses that can cause vesicles.

Other Causes of Vesicles

Many other things can cause vesicles. Some, like friction, are considered minor. If you’ve ever broken in a new pair of shoes, played several rounds of tennis, or done a few hours of manual labor, you’ve probably dealt with these types of friction blisters.

Other causes include:

  • Burns
  • Exposure to chemicals
  • Eczema, a skin condition that results in a rash that can develop oozing blisters
  • Fungal infections like tinea pedis (ringworm)
  • Bullous pemphigoid, a rare autoimmune condition in which the immune system attacks healthy cells in the first two layers of the skin, causing chronic blisters)
  • Pemphigus, a rare type of autoimmune disease in which the immune system mistakenly attacks healthy cells in the skin and mucous membranes, like lining of the mouth

Diagnosis

Vesicles are easy to recognize since they appear on the skin’s surface. But since there are so many potential causes, a healthcare provider can easily misdiagnose them if they don’t do a careful evaluation.

Vesicle diagnosis may include:

  • Medical history
  • Physical exam with dermoscopy (examination of the blisters with a magnifying handheld device)
  • Blood tests
  • STD testing
  • Fungal or bacterial cultures from scabs or vesicular fluid
  • Skin biopsy (a sample of the blister is taken and examined under a microscope)

Treatment

Vesicle treatment depends on the cause. In many cases, healthcare providers treat vesicles with over-the-counter (OTC) medication. Sometimes they heal on their own.

Treatments for vesicles may include:

  • Eliminating or reducing exposure to allergens
  • Cool compress application
  • Colloidal oatmeal bath
  • Calamine lotion
  • Topical steroids and anti-itch creams
  • Nonsteroidal anti-inflammatory drugs (NSAIDs), like Advil (ibuprofen), Aleve (naproxen), aspirin
  • Oral antihistamines
  • Antifungals
  • Antivirals
  • Antibiotics
  • Biologic treatments, medicines developed from a living substance

As tempting as it might be, do not pick or scratch at any lesions. Vesicles may rupture on their own, but you should avoid popping a vesicle deliberately. This can slow healing and make you more prone to developing an infection. It’s best to keep the area clean and any intact vesicles sealed so the skin beneath can heal.

If a vesicle is swollen and painful, a healthcare provider can drain the fluid with sterile tools. Doing so helps the skin to heal effectively without risking infection.

When to See a Healthcare Provider

If you are unsure why you have vesicles, it’s best to see a healthcare provider. A proper diagnosis can ensure you’re using the right treatment to resolve the blisters as quickly as possible.

Getting an evaluation can also ensure that you properly manage any condition or illness that may have caused these lesions.

In addition, be sure to have vesicles evaluated if they are:

  • LargePersistent/multiplyingOver a large part of your bodyChanging color or shape

If you notice any signs of infection, seek medical attention immediately. These include:

  • FeverHeadacheChillsFatigueMuscle achesSwollen lymph nodes

Prevention

Vesicles aren’t always preventable. Those caused by poison ivy or a virus, for example, could appear again after another exposure.

However, you can incorporate some preventative measures to limit your risk of vesicles, including:

  • Avoid your known allergens.
  • Do not share straws, cups, and lip care products with others.
  • Practice good hygiene, especially hand washing.
  • Manage chronic health conditions to limit flare-ups.
  • Use condoms and other barriers when having sex.
  • Catch STIs early with routine screening.
  • Stay current on vaccines, like varicella and shingles.

Summary

Vesicles are fluid blisters that appear on the top layer of the skin. These blisters can break open and leave a crusty, yellow film behind.

Many things can cause blisters, including some bacterial, fungal, and viral infections, autoimmune diseases, chronic skin conditions, and allergies.

Vesicle treatment depends on the cause but may include antibiotics, antifungals, antivirals, topical steroids, NSAIDs, antihistamines, and biologics.

A Word From Verywell

If you have vesicles, you may find it difficult to keep from scratching them. Do your best, since scratching can result in scarring.

Wearing soft mittens or socks over your hands can sometimes help, especially while you sleep.

Frequently Asked Questions

  • Where do vesicles form?
  • Vesicles, also called blisters, can form anywhere on the skin. However, the hands and feet are the most common locations for blisters to develop.
  • Learn More:
  • Causes of Foot Blisters
  • Do vesicles itch?
  • Yes, a vesicle can be itchy. However, try not to scratch since this can cause it to rupture. A broken blister is more vulnerable to infection.
  • Learn More:
  • Rashes with Blisters

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

Yes, a vesicle can be itchy. However, try not to scratch since this can cause it to rupture. A broken blister is more vulnerable to infection.