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A bulla is a fluid-filled sac or lesion that appears when fluid is trapped under a thin layer of your skin. It’s a type of blister. Bullae (pronounced as "bully") is the term used for multiple bulla.

To be classified as a bulla, the blister must be larger than 0.5 centimeters (5 millimeters) in diameter. Smaller blisters are called vesicles.

Picture of bullae

Symptoms of bullae

It’s easy to see if you have bullae. The skin that is affected will be slightly raised and usually have clear fluid inside.

If you have infected bullae, the liquid inside them may appear milky. If your bullae are a result of trauma, they may contain blood as well.

When to see your doctor

Consider seeing your doctor if you notice bullae to receive the correct diagnosis and treatment. This is especially important if the area is painful or restricts your movement, or your bullae contain blood.

You’ll also want to consult with your doctor about your bullae if you have circulatory issues or diabetes. These conditions increase the risk of your bullae getting infected.

Sometimes bullae form in reaction to medications or are accompanied by fever. These cases require immediate medical attention.

Depending on the nature of your bullae, your doctor may suggest home treatment. Or they may drain the blister during your visit.

Treating bullae

There are a variety of treatments for bullae, depending on the cause and if they need to be drained. This includes home, professional medical, and alternative treatments.

Home treatment

Bullae caused by friction can usually heal naturally if they’re left alone.

To avoid further irritation or making your bullae worse, put a protective bandage over the area. A gauze pad is best because the fabric absorbs moisture while still allowing your bullae to breathe.

Don’t try to burst or pop your blisters on your own. If you break the skin to drain your bullae, you risk allowing bacteria into the wounds. This can lead to an infection or make your condition worse.

Medical treatment

If your bulla or blister needs to be drained, your doctor should perform the procedure. This will lower your risk of infection.

During your visit, your doctor will likely swab the area with a cleanser to remove any dirt or bacteria. Then they will puncture your blister using a sterile instrument.

After the blister has drained completely, your doctor will apply a dry bandage to the area. After a few days, you may choose to remove the skin that was covering your bullae if it has dried. Clean scissors with iodine and use them to remove the extra skin if it’s no longer firmly attached to you.

Alternative treatments

There are several alternative treatments you can use to treat and soothe bullae.

Aloe vera: Applying aloe vera directly to the bulla can help soothe pain. It’s a natural anti-inflammatory, so it can soothe any swelling or redness. Aloe vera is most effective when treating small burns that cause blisters. Burns greater than 1 inch in size should be evaluated by your doctor.

Compression wrap: An elastic wrap like an ACE bandage can provide padding and reduce rubbing when the blister is caused from friction.

Pain reducing medications: Over-the-counter acetaminophen or ibuprofen can be used to relieve the discomfort of a blister.

Wet black or green tea bags: There’s no scientific proof that these home remedies work in treating blisters. But some people may find relief in using them.

Complications of bullae

Bullae are typically easy to treat. They will resolve on their own without treatment if not due to an illness or skin condition. However, in some cases complications are possible.

If open or drained, bullae have the potential to become infected. Infections can be particularly dangerous in those with nerve damage.

Some medical conditions increase the likelihood of infections from blisters. These conditions include:

Causes of bullae

Bullae are common occurrences that can be caused by various medical and environmental factors.


One of the most common causes of bullae is friction. This includes the friction that occurs from using a shovel or other tool, or rubbing against the inside of a shoe. Friction blisters appear most often on your hands and feet.

Contact dermatitis

If you come into contact with things that irritate your skin, like latex, cosmetics, or poison ivy, you could develop a condition called contact dermatitis. This is an allergic reaction that also causes bullae.


Infection by certain viruses can result in bullae appearing on your skin.

For example, many people who have shingles, which is caused by a virus, will experience bullae as a symptom. These will often appear as a single stripe of fluid-filled blisters that break easily. The blisters may emerge on the face, neck, or torso and are very painful.

Closely linked to shingles, chickenpox can also cause bullae.

In many cases, the blisters that appear as a result of a viral infection can help diagnose that infection.

Other causes

Other potential causes of bullae include:

Preventing bullae and blisters

Not all bullae can be prevented, especially those caused by medical conditions. However, some simple steps can help you to avoid them.

Use bandages and protective covering: To prevent developing a bulla as a result of friction, try placing a bandage or protective covering over the irritated or bulla-prone area. You can wear gloves to protect your hands when necessary.

Protect your feet when playing sports: If you play sports, there are socks available with additional padding for areas of the foot prone to blistering. You can add fabric like moleskin to your shoes if they rub on your skin. Moisture-wicking socks can also be helpful.

Avoid sunburn: Wearing sunscreen or long-sleeved clothes can prevent bullae from sunburn.

Vaccinate against conditions that cause bullae: Vaccinations are available to prevent chickenpox and shingles. Medications are also available to reduce bullae and other symptoms from herpes outbreaks.


Bullae typically heal on their own within a week. Keeping the area clean, dry, and covered can help prevent infection and promote healing. Covering bullae with fresh bandages can prevent more irritation or unintentional disruption.

If a blister shows any signs of infection, is painful, or is accompanied by a fever, consult a doctor. You may need antibiotics or other treatments. You should also see your doctor if the bullae spreads or doesn’t get better.

If you think the bullae is the result of an illness, your doctor can prescribe medication to reduce your symptoms.

Content licensed from:

Written by: Carmella Wint
Medically reviewed on: Nov 23, 2016: Judith Marcin, MD

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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