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Introduction and Summary

Swollen lips occur when a person’s lips are inflamed or full of fluid, and can range from slightly uncomfortable to downright painful. Lip swelling can come from a variety of causes, from external factors like injury, irritation to allergies, infection, and rarely, underlying conditions that may require medical treatment.

Sometimes, swollen lips can come on suddenly after exposure to an irritant or allergen. Other times, your lip swelling may progress more slowly, or come and go over time. Along the same lines, you may experience a swollen lip on one side or swelling around your entire mouth.

There isn’t just one cause of swollen lips, so there’s no one “swollen lips cure” or timeframe for how quickly the swelling will go away. For example, if you have chapped lips, your lip swelling may go away when you apply chapstick. But if your swollen lips stem from an allergy, the swelling may last until an antihistamine medication kicks in.

While most cases of swollen lips aren’t serious, if you’re experiencing prolonged swollen lips, it’s important to seek medical care. Your doctor can not only help you determine the cause of your swollen lips, but also the best course of action for treating them.

In this article, I’ll cover:

Symptoms That Occur With Swollen Lips

Lip swelling, sometimes called lip edema, occurs when one or both lips are enlarged due to either inflammation or fluid buildup in the lip tissue. Sometimes, swollen lips occur with other symptoms that can signal an underlying cause or condition. Common symptoms that may accompany swollen lips include:

How swollen lips manifest, and how long they last, depends on what’s causing them. Sometimes, swollen lips come on quickly and go away with time or treatment. Other times, swollen lips develop slowly over the course of time, which may be a sign of inflammation or infection.

Common Causes of Swollen Lips

Swollen lips can stem from a number of causes, all of which have their own symptoms and treatment methods. The primary causes of swollen lips include infection, allergies, and injury.

Swollen lips due to infection

Sometimes, swollen lips can occur due to a viral, bacterial, or fungal infection in the body, such as:

  • Cheilitis: An infection, that is often caused by fungus, which causes inflammation around the mouth and often begins in the corners of a person’s lips.
  • Cellulitis: A bacterial skin infection that may manifest around a person’s mouth if that area of skin is infected.
  • Herpes simplex: A contagious viral infection that often results in cold sores around the mouth.

Sometimes, infections―especially more severe ones—present with other symptoms, including redness around the affected area, or mild, flu-like symptoms such as a low-grade fever, body aches, and swollen lymph nodes.

Swollen lips due to allergies

Swollen lips can occur when a person has an allergic reaction, which happens when the immune system reacts abnormally to a foreign substance. Possible allergic reactions, which can range from mild to severe, include:

  • Food allergies, most commonly to nuts, eggs, milk, and fish or shellfish
  • Hay fever or an allergic response to an animal, dust, or pollen in the air
  • Insect bite allergy, such as from a bee sting
  • Drug allergies, most commonly to penicillin

One particular—and potentially life-threatening—type of allergic reaction which can cause swollen lips is a reaction to a class of high blood pressure medications called ace inhibitors. Sometimes this type of reaction will cause swelling only on one side of the lip and the swelling can be dramatic and worsen quickly. If the tongue becomes swollen as well, the airway can become occluded, so if you take this type of medication and develop lip swelling, you should immediately seek medical attention.

Another severe reaction, known as anaphylaxis or anaphylactic shock, may occur in some people with allergies. Usually, anaphylaxis happens a few minutes or a few hours after an encounter with an allergen and can become life-threatening. Symptoms to look out for include:

Swollen lips due to irritation

Trauma or irritation to the mouth area can also prompt the lips to swell. Common external triggers include:

  • Laceration (a cut) on the lip
  • Burns, including sunburn
  • Surgery on the lip or mouth
  • Hot or spicy food
  • Dental appliances, like braces
  • Contact with an irritant, like a soap, detergent, or skin cream
  • Cosmetic surgery, like lip fillers
  • Dry weather or dehydration, which can cause lips to chap and potentially swell
  • A swollen pimple on lip or mouth skin

If you have a swollen lip on one side, it’s more likely your swelling is from injury to that side of your lip than a systemic issue, like allergies.

Other causes of swollen lips

Some people may also experience swollen lips due to:

  • Obesity
  • Malnutrition
  • A reaction to a blood transfusion
  • Fluid retention, which may occur during pregnancy
  • Hereditary angioedema, a genetic disorder that causes swelling that may be triggered by stress
  • Lip cancer, a type of skin cancer
  • Heart, kidney, or liver failure
  • Pre-eclampsia, a condition during pregnancy that includes swelling and high blood pressure
  • Hypothyroidism, which may also present with a puffy face or enlarged tongue
  • Vitamin B2 deficiency

Diagnosing Lip Swelling

The swollen appearance of your lips may be enough for your doctor to diagnose you with lip swelling; however, your provider will likely want to get to the bottom of what’s causing your lips to swell.

If you’re experiencing swollen lips, it’s important to see your health care provider or chat with a K doctor, who can help you get to the bottom of why your lips are swelling and determine how to get rid of a swollen lip.

Your practitioner will likely conduct a physical exam and ask you a series of questions, including:

  • When your lip swelling started
  • If your lip swelling comes and goes
  • If you ate or came into contact with anything new or unusual, such as a food or an insect
  • Whether you have other symptoms, and what they are

If you’re still not sure what’s triggering your swollen lips, your doctor may recommend you keep an allergy journal to help narrow down the cause. He or she may also recommend skin-prick allergy testing to figure out what you’re allergic to so you can avoid triggers.

Treatment for Swollen Lips

While lip swelling can be uncomfortable and frustrating, there are a number of treatments available for infections, allergies, and other causes of swollen lips. Figuring out what’s causing your swollen lips is an essential step for determining the most effective way to treat them.

Treatment for infections

How your doctor treats your infection depends on the type of infection you have. While bacterial infections respond to oral or topical antibiotics, viral and fungal infections do not, although herpes simplex infections can be treated with antiviral medications. Your provider will work with you to decide on the treatment most appropriate for your specific infection.

Treatment for allergies

If your doctor determines your swollen lips are due to environmental allergies, he or she may recommend an over-the-counter (OTC) or prescription antihistamine medication, such as:

  1. Loratadine (Claritin)
  2. Cetirizine (Zyrtec)
  3. Diphenhydramine (Benadryl)
  4. Fexofenadine (Allegra)

In more severe cases of environmental allergies, a doctor might suggest allergy shots, a form of long-term treatment that works by decreasing sensitivity to allergens.

For food allergies, avoiding the foods you’re allergic to is the only way to prevent a reaction. Your doctor may recommend an epinephrine prescription (EpiPen) if you have a severe allergy.

Treatment for injuries

Most forms of irritation and trauma can’t be prevented. If you’re experiencing swollen lips due to an external factor (but not allergies), talk to your doctor about how to minimize pain or swelling. He or she may recommend:

  • Ice or heat to reduce swelling and inflammation
  • Non-steroidal anti-inflammatory drugs, such as ibuprofen (Advil) or acetaminophen (Tylenol)

Treatment for other causes of swollen lips

If your doctor identifies another cause of swollen lips, he or she will work with you to find the best course of action. Your treatment may be focused on managing symptoms with anti-inflammatory medications (like NSAIDs or corticosteroids) or treating the underlying condition.

Risk Factors and Complications

Anyone with allergies, known or unknown, is at a higher risk for developing swollen lips. Other risk factors for swollen lips include:

  • Obesity
  • Exposure to environmental irritants, like sun or spicy food
  • High-impact sports that could cause blunt force to the lip
  • Pregnancy
  • Mouth surgery
  • Dental or orthodontic work
  • Cosmetic surgery

It’s important to seek treatment for swollen lips to avoid any potential complications. While rare, possible complications that may accompany swollen lips include:

  • Spread of an infection
  • Difficulty breathing or cardiac arrest due to anaphylactic shock
  • Lip or skin deformities

When to See a Doctor

If swollen lips are causing you discomfort or interfering with your life, contact your health care provider or a K doctor, who can help you identify the underlying cause and the most appropriate course of treatment.

If you experience any of the following symptoms, which may indicate a serious condition like an anaphylactic reaction, call 911:

  • Throat tightening
  • A swollen tongue
  • Other swelling
  • Hives or rash
  • Itching in the mouth or throat
  • Breathing problems such as shortness of breath, difficulty breathing, wheezing, or choking
  • Severe distress or a feeling of impending doom

How K Health Can Help

Find out what’s causing your lips to swell. Did you know you can get affordable primary care with the K Health app? Download K to check your symptoms, explore conditions and treatments, and if needed text with a doctor in minutes. K Health’s AI-powered app is HIPAA compliant and based on 20 years of clinical data.

Dr. John Bernard, MD

Dr. Bernard is an emergency medicine physician. He graduated from Jefferson Medical College in Philadelphia, and did his residency in emergency medicine at the University at Buffalo.

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