Lips can become swollen if fluid builds up in the skin tissue or if there is underlying inflammation. Causes include allergic reactions, angioedema, and injuries.

Swollen lips have a range of causes, which vary from normal to potentially dangerous.

In this article, we look at what causes swollen lips, how to treat them, and when to see a doctor.

A woman touching her lips -1.Share on Pinterest
Westend61/Getty Images

There are a range of causes for swollen lips with different symptoms, including skin conditions and severe allergic reactions.

It is essential for people with swollen lips to identify their specific symptoms and potential causes so that they can receive appropriate treatment.

Additional symptoms can include:

  • redness
  • soreness
  • sensitive to the touch
  • cracked skin

Often, lips swell because of an allergic reaction to substances in the environment, foods, or medications. These three triggers are discussed below.

An allergic reaction is an immune system response that occurs when the body reacts negatively to a certain substance.

When a person has an allergic reaction, certain cells in the body produce and release a chemical called histamine.

Histamine’s job is to protect the body, but in doing so, it causes swelling and often itching as part of an inflammatory response.

The American College of Allergy, Asthma, and Immunology (ACAAI) estimates that more than millions of Americans have some form of allergy.

People can be allergic to many different things, but some common allergies that can cause swollen lips include:

Environmental allergies

Environmental allergies are allergic reactions to substances found in the environment.

Common allergies include pollen, mold spores, dust, and pet dander (tiny particles of skin shed by an animal).

Symptoms of an environmental allergy include:

  • swelling of the lips and other areas of the body
  • wheezing
  • hives
  • sneezing
  • a blocked nose

Depending on the severity of the allergic reaction, a person can often treat the allergy with an over-the-counter antihistamine.

In more serious cases, a person can get a series of allergy shots, also called immunotherapy, to help the body get used to the allergens.

Food allergies

The ACAAI reports that almost 6% of American adults and children have a food allergy.

Allergies tend to run in families, but it is impossible to predict if a parent will pass an allergy on to their child.

About 90% of food allergies involve the following foods:

Besides swollen lips, the ACAAI lists the following symptoms of food allergies:

The main way to manage a food allergy is to avoid the food that triggers it. This can involve reading labels carefully and asking about ingredients at restaurants.

A dietitian or nutritionist can often advise on the best course of action regarding a diet for a specific allergy.

Other allergies

Insect bites, stings, and allergies to specific drugs can also cause the lips to swell.

Some people have allergies to particular medications. This can include antibiotics, penicillin is usually the main culprit.

Other common symptoms of a penicillin allergy include:

  • rashes
  • itchy eyes
  • hives
  • wheezing
  • swollen tongue or face
  • feeling sick
  • vomiting
  • diarrhea
  • headache

If a person experiences these symptoms after taking a medication that contains penicillin, they should stop taking it immediately and consult their doctor. Other medication options are often available.

Other drugs that can cause an allergic reaction that may be like this include nonsteroidal anti-inflammatory drugs (NSAIDs), anticonvulsants, and drugs associated with chemotherapy.


Serious allergic reactions can be in the form an acute allergic reaction, called anaphylaxis. When anaphylaxis is severe, a person can have anaphylactic shock.

This reaction can be dangerous and, according to the American Academy of Allergy, Asthma, and Immunology (AAAAI), even fatal. Some people may not even realize they have an allergy to something until they experience anaphylaxis.

The AAAAI lists five groups of symptoms of anaphylaxis:

  1. Breathing. Wheezing, tight throat, chest pain, difficulty swallowing, blocked nose.
  2. Circulation. Pale or blue skin, weak pulse, light-headedness, low blood pressure.
  3. Skin. Hives, swelling, itchiness, warmness, redness, a rash.
  4. Stomach (abdomen). Nausea, cramps, vomiting, diarrhea.
  5. Other. Symptoms include anxiety, a headache, and itchy red eyes.

Anaphylaxis requires immediate medical treatment. The first course of action is to inject a dose of epinephrine, such as through an EpiPen, and then to get to an emergency room.

Aside from allergies, some other things can cause swollen lips. These include:


This is typically a short-term condition that happens when there is swelling under the skin.

It often occurs as an adverse side effect of a medication or in response to a trigger that causes an allergy.

Angioedema often affects the lips along with other body parts, including:

  • hands
  • feet
  • around the eyes
  • tongue
  • genitals

Angioedema is not considered to be a serious condition, and it will usually go away on its own within a few days.

If angioedema is caused by an allergy, then an antihistamine is the usual treatment method.

If it is caused by a medication, a person may need to stop the current course of treatment and see their doctor to find an alternative.


Minor cuts, wounds, and lacerations to the lips can cause swelling. The lips have a rich blood supply, so they are susceptible to swelling.

To treat lip injuries, clean the area and stop any bleeding with a clean cloth or bandage. It is also possible to reduce swelling by applying an ice pack to the affected area.

A person should seek help from a healthcare professional if the injury is:

Rare medical conditions

A rare condition that can cause swollen lips is granulomatous cheilitis.

  • Granulomatous cheilitis is a recurrent and firm swelling of the lips. Causes include an allergy, Crohn’s disease, sarcoidosis, or orofacial granulomatosis.
  • Miescher-Melkersson-Rosenthal syndrome is a recurrent, long-lasting swelling of one or both lips (granulomatous cheilitis) with facial muscle weakness and a fissured tongue. There is no known cause, though genetics may be a factor.

Both conditions can usually be treated with prescription medication, although in some cases, surgical reduction may be necessary. If there is an underlying cause, treatment should address it.

There are several reasons as to why lips become swollen, but in most cases, it is not serious and will disappear on its own.

Anyone with swollen lips should see a doctor if they are experiencing severe symptoms, such as those associated with anaphylaxis.

Most cases of swollen lips do not require emergency care and will often go away on their own within a few days.

Identifying the underlying cause of swollen lips is essential. If a person requires treatment, such as in the case of an allergy, they should see a doctor for an accurate diagnosis.

There may be several reasons why a person’s lips are swollen, ranging from common allergies to rare medical conditions. In most cases, the swelling is not serious and will disappear on its own.

Still, a person should seek help if they experience severe symptoms or have concerns about their swollen lips.