Possible Causes of Swollen Lips

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Several conditions can cause swollen lips. Some can be serious or even life-threatening, while others may resolve on their own. See your doctor if:

  • You have swelling that cannot be explained
  • The swelling doesn't improve after a few days
  • You also have difficulty breathing
  • If you suspect any of the life-threatening conditions covered below

This article looks at some of the causes of swollen lips.

Swollen lips causes
Verywell / Nusha Ashjaee


Swollen lips are a symptom of oral allergy syndrome (OAS). When you have this type of allergy, certain foods trigger a tingling mouth and allergic inflammation. OAS is rarely considered serious. It usually resolves on its own within an hour.

Angioedema is a more concerning allergic reaction. It can be triggered by a few different things, including:

It causes swelling of the lips, face, and tongue. Symptoms usually appear rapidly. There may also be redness, bumps, or hives. The swelling may make it hard to talk.

Angioedema can be life-threatening if it affects the windpipe. Call 911 if the swelling is accompanied by:

  • Wheezing
  • Difficulty breathing
  • Cyanosis or bluish lips, fingers, or skin

Angioedema emergencies can be treated with epinephrine. This drug helps the muscles in your airway relax so you can breathe.

If you have had this type of reaction, you should carry an EpiPen (epinephrine). Symjepi (epinephrine) is a single-dose option. Have one of these two choices on hand at all times.


Trauma to the face or lips can cause swelling. This might happen if you burn your lips on hot food or are hit in the mouth. In minor cases, the swelling can be controlled with a cold pack. It will usually resolve in a few days.

See your doctor at once if you have a cut on your lip that is:

  • Deep
  • Bleeds excessively
  • Causes a lot of pain
  • Is larger than 1/4 inch (6 mm)

If you have a large cut on your lip, it is important to see a doctor within 24 hours. If the injury is older than that, it can't be treated with stitches, especially if it is very swollen or there is a risk of infection. Instead, your doctor will clean the wound and schedule a repair in a couple of days.

If you have stitches close to your lips, follow these care guidelines:

  • Eat soft foods for two to three days.
  • Avoid spicy food until the wound heals.
  • Rinse your mouth with water after every meal. This will help remove debris from the wound.
  • Do not drink with a straw. The sucking motion creates negative pressure that might damage the repair.

Chapped or Sunburned Lips

Very chapped lips may become swollen. Chapped lips can happen if you live in a dry climate, if you lick your lips too much, or if you spend time outside in windy, sunny, or arid weather. To prevent this, try any or all of the following:

  • A lip balm containing petroleum jelly or beeswax
  • Lip products with sunscreen
  • Wearing a hat
  • Not licking your lips
  • Not picking at dry, flaky skin


Some infections may cause lip swelling. This includes infections caused by funguses, viruses, or bacteria.

Sometimes germs can infect chapped, cracked lips. This can cause redness, soreness, and some swelling. If you have an infection, treatment will depend on what's causing it. Infections should always be managed by your doctor.

An infection should be considered serious if it is accompanied by:

  • A fever over 100.4 F
  • Shaking chills
  • Nausea or vomiting
  • Pus discharge

If you have any of these symptoms, see your doctor or go to the nearest urgent care center.


Mucoceles are cysts that form after you bite your lip or experience an injury that damages a salivary gland. The fluid backs up or pools under the skin in that area and forms a bump.

Mucoceles can vary in appearance, but usually appear as bumps rather than as generalized swellings. They are not considered a serious health problem, though some may be bothersome. If so, they can be surgically removed or lanced and drained.


A few different things can cause swollen lips. Some are much more dangerous than others.

An oral allergy may cause inflammation. This kind of reaction usually improves within an hour. A more serious reaction may also cause swelling of the tongue or face. If you have wheezing and trouble breathing, seek medical care at once.

Other causes of swollen lips include injuries, chapped or sunburned lips, mucoceles, and infection. Make sure to see your doctor if you have a deep cut or signs of infection like fever, chills, and vomiting.

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3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American College of Allergy, Asthma, and Immunology. Pollen food allergy syndrome.

  2. Bryan YF, Johnson KN. The difficult airway in adults with angioedema. Anesthesiology News Airway Management. 2018.

  3. Senthilkumar B, Mahabob MN. Mucocele: an unusual presentation of the minor salivary gland lesionJ Pharm Bioallied Sci. 2012;4(Suppl 2):S180-S182. doi:10.4103/0975-7406.100265

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