Why Is My Lip Swollen? Types, Signs, Diagnosis, and Remedies


Why is my lip swollen for no reason?

There are several possible causes of sudden, unexplained lip swelling. Allergies, infection, inflammation, and injury are a few of the most common. An allergic reaction can cause lips to swell quickly, often with other symptoms such as hives, itching, or difficulty breathing.

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Enlarged or swollen lips happen for many reasons, ranging from allergies and infection to trauma or injury. In this article, we will explore the various causes of swollen lips and what can be done to treat them.

Why Are My Lips Swollen?

Virtually all swelling is the result of the same biological process: inflammation. When something affects the body, environmentally or internally, it responds by firing off defensive systems. Inflammation is the go-to reaction, where fluid and blood are sent to the affected area to prevent further damage.

It's this internal process that causes tissues to enlarge and swell. Depending on the cause, the swelling can be temporary or prolonged.

Swelling that occurs in the lips may be due to direct contact with the thing responsible for causing swelling or swelling as part of the body's greater reaction to an irritant or illness.

What Causes Swollen Lips?

Lips can swell as a result of many things, both environmental and biological. In some situations, they'll become enlarged immediately after exposure to something, while in others, the swelling will occur progressively or chronically. Read below for a breakdown of the most common factors behind swollen lips.


Swollen lips are most commonly associated with allergic reactions on the lips. They can occur as a part of the body's immune response as it attempts to flush an allergen out of its systems. This is basically the same inflammatory process discussed earlier but is specifically caused by a release of histamine.


Dermatitis is a broad term used to describe general skin irritation. While it can take on many forms, the most common is contact dermatitis. This type of reaction occurs when the skin comes into direct contact with an irritant, be it food like eggs, soy, nuts, or shellfish, chemical, or other foreign substance.


Swollen lips are just one of the many odd symptoms associated with COVID-19. The virus is known to cause rashes and inflammation in different parts of the body, sometimes including the mouth.

Trauma or Injury

Direct trauma to the mouth or tissues of the lips can cause inflammation and swelling. This could be the result of a physical blow, but it also applies to insect bites and activities like biting or sucking on the lips too hard. In any case, the swelling should dissipate after the affected area has healed.

Sunburn or Dry Lips

The skin on and around the lips is particularly vulnerable to environmental assaults, as it's thinner and more delicate than other areas of the body. Sunburns and dehydration can lead to chapped lips, which in turn can cause them to swell up. In most cases, the swelling will go away on its own with the application of lip balm and other moisturizing treatments.

Dental Issues

Certain infections of the mouth - like a periodontal disease - can manifest in the form of swelling. The inflammation is typically localized to the area around the gums and lips but may spread to the lips if left untreated. Dental tools are also potential culprits, as poorly-fitted braces and other equipment can lacerate the gums and lips, causing them to swell.

Spicy Food

Some food is so spicy that it's capable of physically distressing the tissues of the mouth. Eating dishes containing ingredients like chilis, peppers, and other spicy substances can irritate the lips to the point that they swell with inflammation from direct contact.

Lip Cancer

Cancerous tumors can sometimes form on the lips, which can cause swelling and other symptoms. It's important to note that this type of lip swelling is rare and typically accompanies other symptoms, such as lumps or bumps. If you suspect any type of cancerous growth, it's best to contact a doctor immediately.

Swollen Lip Symptoms

Swollen lips generally indicate that the body is responding to some sort of irritation or injury; they're really a symptom, not a condition on their own. However, there are some telltale signs of lip swelling that you should be aware of.

Here's a look at the most common symptoms:

Enlarged Appearance

Swelling is defined as an increase in size, and this is exactly what you'll notice with swollen lips or a swollen tongue. The affected area should appear larger than the surrounding tissue, and may even feel puffy or tender to the touch.

Redness and Irritation

The area around the lips may appear red or inflamed, and you may also feel a burning sensation when you touch it. Dryness and cracking due to irritation can sometimes cause bleeding as well.

Tenderness and Pain

The body's inflammatory response typically causes pain and tenderness to the affected area. This may manifest as an ache, sting, blisters, or another form of discomfort in the lips.

Why Is My Lip Swollen on One Side?

Not all cases of swollen lips look the same - for some individuals, the enlargement may affect only one lip or a specific side. In these situations, it's likely that the cause is localized to a certain area of the mouth and not part of a bigger physical response.

Trauma, infection, or even cancer can cause lip swelling on one side only; general immune reactions, on the other hand, usually affect both lips at once.

How to Get Rid of a Swollen Lip Overnight

Swollen lips are incredibly uncomfortable. Fortunately, there are several home remedies you can try to reduce the swelling and get relief.

Use a Cold Compress

Cold ice compresses are a fast and effective way of slowing inflammation and pain. To create one, simply wrap a few ice cubes in a thin cloth and apply it to your swollen lip for up to 10 minutes at a time.

Baking Soda

Baking soda, scientifically referred to as sodium bicarbonate, has anti-inflammatory properties that can help lessen the discomfort of the body's immune response. It's best applied as a paste, with equal parts baking soda and water. Gently rub the paste onto the affected area and leave it on for 10 minutes before washing it off with cold water.

Cucumber and Aloe Vera

These two natural substances can be applied directly to the lips to reduce swelling. Cucumber can cool the affected area and relieve inflammation, while aloe vera has soothing properties that can help with discomfort.

Try Herbal Remedies

Natural remedies like calendula, chamomiles, and fenugreek may help reduce swelling, pain, and irritation. Create a paste using these ingredients mixed with water or honey then apply it to the swollen area.

When to See a Doctor

There are times when a swollen lip is nothing to worry about, and home remedies can help the swelling go away. But there are also situations where swollen lips are indicative of a more serious problem, such as anaphylaxis, and medical attention is necessary.

If your swollen lips have persisted or worsened over 24 hours, or are accompanied by other symptoms like difficulty breathing, severe distress, or a fever, seek medical attention immediately. A healthcare provider will be able to assess your condition and determine the best course of action.


If you suspect that allergies are behind your swollen lips, the best way of confirming it is with an allergy test. There are two main ways of getting one: skin prick allergy tests and at-home allergy tests.

The conventional approach to testing for allergies is through a skin prick test. This involves introducing small amounts of different allergens to your skin and observing the reaction. It must be conducted under the supervision of a medical professional and can be very uncomfortable.

At-home testing is a newer alternative to allergy diagnosis, allowing you to order a kit online and conduct the test in the comfort of your own home. These tests are more convenient and only require a small blood sample via finger prick.


If testing confirms that your swollen lips are indeed due to allergies, there are a few treatment options to consider.

Mitigation and Avoidance

Try to reduce exposure to things that can trigger environmental allergies by staying indoors on days with high pollen levels and avoiding potential allergens like pet dander, mold spores, dust mites, and certain chemicals or foods.

Over-the-Counter Medication

Over-the-counter (OTC) antihistamines can help reduce the swelling and discomfort of allergic reactions. It's important to remember, however, that OTC medications are short-term solutions and will not eradicate your potential for developing symptoms.

Prescription Medication

If your allergies are severe, a doctor may be able to prescribe you epinephrine or corticosteroids. Epinephrine, most well-known by the brand name EpiPen, can help reduce swelling and provide relief in emergency situations. Corticosteroids are taken as pills or injections and can help to reduce inflammation and suppress an overactive immune response.

Allergy Immunotherapy

Allergy immunotherapy is a medical treatment designed to help people with allergies find long-term relief. It works by gradually exposing the patient to a small amount of the allergens they’re allergic to, which helps the body build a tolerance to it. This treatment can be done in two different forms: subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT).

Generally referred to as allergy shots, SCIT involves the injection of a small amount of allergen into the skin. With repeat injections, the body becomes less sensitive to the allergen and can eventually be tolerated.

SLIT is a less invasive form of immunotherapy that involves placing drops or tablets of allergens under the tongue for absorption by the salivary gland. Unlike allergy shots which must be administered in a doctor’s office, SLIT can be safely taken at home.

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