A person may wake up with a swollen lip due to a mild allergic reaction or from an injury. In other cases, it may be a sign of a condition that needs medical treatment.

It may be hard for a person to identify what has caused their lips to swell by remembering the activities and food they ate the day before.

This article looks at different causes behind waking up with a swollen lip, and how to treat it.

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Below are some of the more common possible causes of waking up with a swollen lip.


Angioedema refers to the rapid swelling of an area under the skin that typically affects the:

  • face, such as the eyelids, mouth, and tongue
  • limbs, such as hands or feet
  • genitals

It is similar to a skin condition called urticaria, or hives, which causes a rash on the skin. However, angioedema affects the deeper layers of skin, or the subcutaneous and submucosal layers.

The cause of angioedema depends on its type:

  • Allergic: Allergens, such as insect or animal bites, contact with latex, taking certain medications, or eating certain foods.
  • Drug-induced: Taking angiotensin-converting enzyme (ACE) inhibitors or non-steroidal anti-inflammatory drugs (NSAIDs).
  • Hereditary: A problem with the C1 inhibitor protein.

Angioedema typically goes away after three days.


Allergic reactions to food, medication, or certain materials may cause the lip to swell.

Allergic reactions to food usually develop within minutes of coming into contact with the food. If a person experiences a severe allergic reaction (anaphylaxis), they should get immediate medical attention as it can be life-threatening.

Some allergic reactions may take hours to develop.

For example, the American Academy of Allergy, Asthma, and Immunology (AAAAI) indicates that an allergic reaction to medications develops anywhere from minutes to two weeks. Sometimes, reactions may happen after six weeks.

Oral allergy syndrome

Oral allergy syndrome is a type of allergic reaction that causes swelling and itchiness in the:

  • lips
  • mouth
  • throat
  • tongue

It is caused by eating certain foods with proteins that are similar to those found in pollens that cause hay fever. Typical triggers include raw fruits and vegetables or some nuts and seeds.

If a person wakes up with swollen lips, they may have eaten food that triggered a reaction overnight or developed a medication sensitivity over time.

Anaphylaxis: Symptoms and what to do

Anaphylaxis is a severe allergic reaction that can be life threatening. The symptoms develop suddenly and include:

  • hives
  • swelling of the face or mouth
  • wheezing
  • fast, shallow breathing
  • a fast heart rate
  • clammy skin
  • anxiety or confusion
  • dizziness
  • vomiting
  • blue or white lips
  • fainting or loss of consciousness

If someone has these symptoms:

  1. Check whether they are carrying an epinephrine pen. If they are, follow the instructions on the side of the pen to use it.
  2. Dial 911 or the number of the nearest emergency department.
  3. Lay the person down from a standing position. If they have vomited, turn them onto their side.
  4. Stay with them until the emergency services arrive.

Some people may need more than one epinephrine injection. If the symptoms do not improve in 5–15 minutes, or they come back, use a second pen if the person has one.

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Cellulitis is a bacterial infection that affects the fat and soft tissue in the deeper layers of the skin. It typically affects the arms and legs, but it may also develop around the mouth.

Cellulitis may cause an area of skin to suddenly become:

  • swollen
  • red
  • tender
  • painful
  • bruised

If a person experiences symptoms of cellulitis they should get immediate medical help, as it may be life-threatening.

Cellulitis is typically treated with antibiotics.


Orthodontic braces may cause swelling and irritation when they rub against the soft tissue on the inside of the lips and cheek.

The most common type of braces are made from stainless steel. However, if people are allergic to one of the alloys, such as nickel, a person may consider ceramic braces.

Trauma to the face may also cause a person with braces to get a swollen lip. This may be because a person’s lip or cheek tissue can become caught in the metal wire or brackets. Separating the lip tissue from the brace can then cause more trauma to the lips, causing swelling as they heal.

Wearing a mouthguard when playing sports or using dental wax to cover the braces may protect a person’s lips or cheeks from getting caught in their braces.


Injury to the mouth and lips may cause swelling. The lips contain a lot of blood, and they can bleed heavily.

That said, they also heal quickly and do not often need stitches.


Sunburn is an inflammatory skin reaction that may cause swelling.

If a person exposes their face to strong sunlight during the day, they might wake up with swollen lips. This is because the peak reaction to sunburn happens 24-36 hours after exposure.

Anti-inflammatory medications may help reduce swelling, but a person needs to start this treatment before the skin changes color.

Focal dystonia

Focal dystonia is a neurological condition. It affects a particular muscle or muscle group in one area of the body, causing involuntary muscle contractions and postures.

Cranial dystonia affects muscles in the face, including the lips.

A person with oromandibular dystonia may experience difficulty:

  • swallowing
  • chewing
  • speaking
  • opening and closing the mouth

They may also experience tongue spasms.

Embouchure collapse

An embouchure collapse, or embouchure dystonia, affects the:

  • lower facial muscles
  • tongue
  • jaw
  • pharynx

The embouchure is a specific position in which wind and brass instrument players position their facial muscles to produce sound from their instrument.

A musician might notice the symptoms of embouchure collapse by feeling pain while playing. It can include tremors and involuntary muscle contractions of the mouth, jaw, and tongue.

Embouchure collapse may occur if a person plays their instrument too much. Stopping to play for a while may help prevent embouchure overuse and collapse.

Rare conditions

Some rare medical conditions may also cause swollen lips:

Treatment for swollen lips depends on the underlying cause.

It is important to see a doctor if a person wakes up with a swollen lip. They will be able to assess the individual’s symptoms and develop a treatment plan based on their condition.

Some treatment methods may include:

Some natural and home remedies may also help a person reduce swelling in their lips, including:

When should I go to the ER for a swollen lip?

A person should get immediate medical help if they are experiencing a severe allergic reaction or signs of cellulitis, which may include rapid swelling, heat, and tenderness in an area of skin.

Symptoms that require urgent medical attention are:

If a person’s swollen lip does not get better after three days, they should see a doctor.

A person may wake up with a swollen lip for various reasons. Trying to remember what they had done, where they had been, or what they had eaten the day before may help quickly determine the cause.

If there are signs of injury, infection, or signs of a more severe illness, a person should seek medical advice quickly to start appropriate treatment as soon as they can.