Swollen Lip (Lip Edema): Causes and Treatment

Causes of lip swelling

Allergic angioedema

Angioedema is swelling in the deeper layers of skin. When triggered by allergy, it comes on within minutes to 2 hours of exposure, often with hives, itching and redness. Common triggers:

• foods: peanuts, tree nuts, shellfish, fish, eggs, milk, sesame
• medicines: penicillins and other antibiotics, NSAIDs such as ibuprofen and aspirin
• insect stings
• latex
• lip products, toothpaste flavorings and cosmetics (contact allergy, usually slower and itchier)

Allergic swelling can be part of anaphylaxis, a whole-body reaction that can close the airway.

Medicine-induced angioedema without hives

ACE inhibitors (blood pressure medicines whose names end in -pril) can cause swelling of the lips, tongue and face without hives or itch. It can start years after beginning the medicine and does not respond well to antihistamines. It needs urgent assessment, and the medicine must be stopped by a doctor. Similar reactions occur rarely with ARBs, gliptins and some other drugs.

Hereditary and acquired angioedema

Hereditary angioedema is a rare genetic condition causing repeated swelling of the lips, face, hands, feet, genitals and gut, without hives, lasting 2 to 5 days. Attacks may follow dental work, injury or stress. It does not respond to antihistamines or epinephrine and needs specific treatment.

Injury

A blow, fall, bite while eating, dental injection or cosmetic filler causes swelling and bruising that peaks within 48 hours and settles over a week. A cut through the lip border needs careful stitching to avoid a visible step.

Infection

• Cold sores: tingling, then a cluster of blisters at the lip edge, often with swelling. See cold sore.
• Cellulitis or abscess: red, hot, painful swelling, sometimes with fever. It can follow a cracked lip, piercing or pimple.
• Dental abscess: an infected upper front tooth can swell the upper lip. See cellulitis or abscess of the mouth.
• Impetigo: honey-colored crusts in children.

Sun and weather

Sunburn and windburn cause swollen, dry, cracked lips. Chronic sun damage causes actinic cheilitis, a rough, scaly lower lip.

Insect bites

A mosquito or other bite on the lip can cause dramatic local swelling for a day or two.

Less common causes

• Orofacial granulomatosis and Crohn's disease: persistent, painless lip swelling, sometimes with mouth ulcers or gut symptoms
• Melkersson-Rosenthal syndrome: recurrent lip swelling, facial nerve palsy and a fissured tongue
• Mucocele: a soft, bluish bump on the inner lower lip from a blocked salivary gland
• Tumors: rare, presenting as a firm lump or non-healing sore

Upper lip vs lower lip swelling

How doctors find the cause

The doctor will ask how quickly the swelling came on, whether there were hives or itching, what you ate, what medicines you take (including recent starts and ACE inhibitors), and whether it has happened before. They check your airway, mouth, teeth and skin. Tests can include allergy testing, C4 and C1 inhibitor blood tests for hereditary angioedema, and a biopsy for long-lasting swelling.

How to reduce lip swelling

• Cold compress: a cloth-wrapped ice pack for 10 to 15 minutes at a time.
• Antihistamines such as cetirizine or loratadine for mild allergic swelling. Follow the label dose.
• Remove the trigger: stop a new lip product, avoid the suspected food, and talk to your doctor about any suspect medicine. Do not stop prescribed medicines without advice, except during an emergency reaction.
• Cold sores: antiviral cream or tablets started at the first tingle.
• Infection: antibiotics or drainage from a doctor or dentist.
• Severe allergy: epinephrine auto-injector, then call 911 or your local emergency number.

Frequently asked questions

What causes a lip to swell suddenly?

Sudden lip swelling is most often an allergic reaction to food, medicine, insect stings or lip products. ACE inhibitor blood pressure medicines, injuries, cold sores and dental infections are other common causes. Swelling with breathing or swallowing problems is an emergency.

How long does a swollen lip last?

Allergic swelling usually settles within 24 to 48 hours once the trigger is removed. Swelling from an injury peaks at 1 to 2 days and fades over about a week. Hereditary angioedema attacks last 2 to 5 days. Swelling lasting longer needs a medical review.

Can stress cause a swollen lip?

Stress does not directly cause lip swelling, but it can trigger cold sore outbreaks and attacks of hereditary angioedema, and it may worsen chronic hives. Lip biting from stress can also cause swelling of the inner lip.

Why did I wake up with a swollen lip?

Common reasons are an allergic reaction to something eaten the evening before, an insect bite overnight, biting your lip in your sleep, a developing cold sore, or angioedema from a medicine. If it keeps happening or involves your tongue, see a doctor.