Swollen lips occur when fluid accumulates within the soft tissues of the upper or lower lip due to inflammation, injury, infection, or an allergic response. For many people, swelling is mild and temporary. However, sudden or rapidly worsening swelling—especially when accompanied by trouble breathing, hives, or swelling of the tongue or throat—can indicate a serious medical condition requiring urgent care. Understanding common symptoms, likely causes, and appropriate treatment can help you decide when it is safe to manage swelling at home and when to seek medical attention.

What Are Swollen Lips?

Swollen lips describe noticeable enlargement or puffiness of one or both lips resulting from inflammation or excess fluid within the tissue. Swelling may develop gradually or appear very suddenly. While minor irritation, injuries, or mild allergies are common triggers, lip swelling may also occur in more serious conditions such as angioedema or infection.

Common Symptoms of Lip Swelling

Symptoms vary depending on the underlying cause and may include:

  • Redness, warmth, or tenderness
  • Visible inflammation or puffiness
  • Itching, tingling, or burning sensations
  • Cracking or peeling skin
  • Blisters or fluid-filled lesions
  • Bruising or sensitivity after injury
  • Rapid swelling that may worsen over minutes

Certain patterns may help point to the cause:

  • Allergic reactions: itching, hives, tingling, watery eyes, or rash
  • Infections: blisters, crusting, localized pain, fever
  • Injury-related swelling: bruising, cuts, or tenderness
  • Angioedema: sudden, deeper swelling of the lips, eyelids, face, or tongue; may interfere with breathing

What Causes Swollen Lips?

Allergic Reactions

Allergies are among the most common causes of lip swelling. Reactions may occur shortly after exposure to:

  • Foods such as milk, eggs, peanuts, tree nuts, fish, shellfish, soy, or wheat
  • Environmental allergens like pollen, dust, mold, or pet dander
  • Medications such as antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), or other prescription drugs
  • Insect stings or bites

Symptoms may range from mild tingling or itching to more significant swelling. In severe cases, reactions can progress to anaphylaxis—a life-threatening condition that may include trouble breathing, wheezing, rapid swelling of the face or lips, dizziness, or fainting.

Angioedema

Angioedema is deeper swelling beneath the skin that often affects the lips, eyelids, face, tongue, or throat. It may be triggered by:

  • Allergens
  • Medications such as ACE inhibitors
  • Hereditary conditions affecting immune regulation

Swelling often develops quickly and may last a few hours to a couple of days. Because angioedema can restrict breathing, rapidly worsening symptoms require immediate medical attention.

Infections

Infections involving the skin or tissues around the mouth can cause lip swelling. These may include:

  • Viral infections: herpes simplex virus (cold sores)
  • Bacterial infections: cellulitis or other skin/soft-tissue infections
  • Fungal irritation: yeast overgrowth around the mouth

Infection-related swelling may be accompanied by blisters, crusting, oozing lesions, pain, or fever.

Injuries or Trauma

Swelling commonly develops after:

  • Accidental lip biting
  • Blunt trauma from sports injuries or falls
  • Burns from hot foods or beverages
  • Dental procedures or injections

Most injury-related swelling improves as the tissue heals.

Irritants and Contact Reactions

Irritation or allergic contact dermatitis may occur after exposure to:

  • Lip balms, lipsticks, or glosses
  • Toothpaste or mouthwash
  • Skincare products
  • Fragrances, dyes, or preservatives

These reactions can lead to redness, dryness, burning, and subsequent swelling.

Environmental Factors

External triggers that may inflame or irritate the lips include:

  • Excessive sun exposure
  • Windburn or dry weather
  • Spicy foods (capsaicin irritation)
  • Cold temperatures

These causes are typically mild and improve with supportive care.

Rare Medical Conditions

Less common diseases may cause persistent or recurrent lip swelling, such as:

  • Granulomatous cheilitis
  • Melkersson–Rosenthal syndrome, which can involve recurrent swelling and facial nerve symptoms

These conditions may require evaluation by a specialist.

How to Treat Swollen Lips

Home Care for Mild Swelling

Mild cases may improve with simple measures:

  • Apply a cold compress for short intervals
  • Use gentle moisturizers to soothe dry or cracked lips
  • Avoid identified allergens or irritants
  • Stay hydrated
  • Avoid picking or biting the lips

These steps can reduce discomfort while the underlying cause resolves.

Medical Treatment

A healthcare professional may recommend:

  • Antihistamines for allergic swelling
  • NSAIDs for pain or inflammation
  • Prescription corticosteroids for more significant allergic or inflammatory reactions
  • Antibiotics or antivirals if an infection is diagnosed
  • Targeted treatment for angioedema or rare underlying conditions

Because treatment varies by cause, proper evaluation is important.

When to See a Doctor

Seek medical care if:

  • Swelling persists longer than 2–3 days
  • You have recurrent or unexplained swelling episodes
  • There are signs of infection (pain, fever, blisters, or oozing)
  • Over-the-counter care does not improve symptoms
  • Swelling follows a dental procedure
  • You suspect a food, drug, or environmental allergy

Persistent or recurrent swelling may require medical evaluation to identify the cause.

When to Seek Emergency Care

Call emergency services immediately if lip swelling occurs with:

  • Difficulty breathing or swallowing
  • Rapid swelling of the lips, tongue, or face
  • Wheezing, chest tightness, or widespread hives
  • Severe dizziness, fainting, or signs of anaphylaxis

These symptoms may indicate a life-threatening reaction and require urgent treatment.

Frequently Asked Questions

Why do lips swell suddenly?

Sudden lip swelling may result from an allergic reaction, angioedema, irritation, injury, or—in some cases—an underlying infection. Allergic reactions and angioedema are among the most common causes of rapid-onset swelling.

How long does lip swelling usually last?

Duration depends on the cause. Many mild cases resolve within a few hours to a couple of days. Clinical guidance notes that swelling lasting longer than 2–3 days should be evaluated by a healthcare professional.

Can spicy foods cause swollen lips?

Yes. Spicy foods containing capsaicin can irritate lip tissue, causing temporary burning or mild swelling. This effect is typically short-lived.

Is lip swelling always caused by allergies?

No. Although allergies are common, swelling may also result from infections, trauma, irritants, environmental factors, or rare inflammatory conditions.

Should I use ice or heat on swollen lips?

A cold compress can help reduce inflammation. Heat is generally not recommended, as it may worsen swelling in many cases, especially when inflammation or injury is present.

APA Reference List

American Academy of Allergy, Asthma & Immunology. (n.d.). Anaphylaxis. https://www.aaaai.org/conditions-and-treatments/library/allergy-library/anaphylaxis

American College of Allergy, Asthma & Immunology. (n.d.). Food allergies. https://acaai.org/allergies/allergic-conditions/food

Cleveland Clinic. (n.d.). Angioedema: Causes, symptoms, types & treatments. https://my.clevelandclinic.org/health/diseases/22632-angioedema

Cleveland Clinic. (n.d.). Granulomatous cheilitis. https://my.clevelandclinic.org/health/diseases/23161-granulomatous-cheilitis

Cleveland Clinic. (2024, August 15). Facial swelling: Symptoms & causes. https://my.clevelandclinic.org/health/symptoms/facial-swelling

Healthline. (2023, March 9). Swollen lips: Causes, treatment, and more. https://www.healthline.com/health/swollen-lips

Medical News Today. (n.d.). Swollen lips: Causes and treatment. https://www.medicalnewstoday.com/articles/321080

Merck Manuals. (n.d.). Angioedema. In Merck Manual Professional Version. https://www.merckmanuals.com/professional/immunology-allergic-disorders/allergic-autoimmune-and-other-hypersensitivity-disorders/angioedema

Mayo Clinic. (2023, October 27). Hives and angioedema: Symptoms & causes. https://www.mayoclinic.org/diseases-conditions/hives-and-angioedema/symptoms-causes/syc-20354908

Vinmec International Hospital. (2025, January 23). Why are your lips swollen when you wake up? https://www.vinmec.com/eng/blog/why-are-your-lips-swollen-when-you-wake-up-en

Verywell Health. (2025, March 17). Hayes, K. 13 causes of swollen lips and how to get relief. https://www.verywellhealth.com/what-causes-swollen-lips-1192167