Lip Sores – Causes and Types of Lesions on the Lips

What are lip sores?

The term “sores” refers to the appearance of skin lesions in any part of the body. Lip sores are lesions such as pimples, scabs, ulcers or blisters that appear on the lips. These sores may also be accompanied by other symptoms such as tenderness, pain, swelling, and even bleeding. The skin on the lips is relatively thin compared to the skin on the other parts of the body. This makes it susceptible to various kinds of injuries. Lip sores due to injury can occur in any individual.

Apart from physical injury, lip sores also occur due to a variety of other causes. In most cases, lip sores develop temporarily and then go away on their own. Temporary lip sores do present a cosmetic problem, and can also affect daily activities (such as feeding or talking) due to tenderness and pain in the lip region. Since temporary sores resolve on their own, there is usually no cause for deep concern.
In some cases, lip sores may persist or be a recurrent problem. Such persistent or recurrent cases of lip sores are usually due to allergies, infections, and other serious underlying ailments. Lip sores that are persistent or recurrent should be looked at by a doctor. Diagnosing the underlying cause of persistent or recurrent lip sores is necessary for determining the appropriate line of treatment for the condition.

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Causes of Lip Sores

Since lip sores can occur due to a variety of conditions, some of which may be serious, it is important to diagnose the exact cause before determining the appropriate course of treatment. If the cause of a lip sore is acute injury, then the condition typically resolves on its own. Proper care of the lip region during this period can help hasten the recovery process and prevent further damage to the lips. However, recurrent or chronic lip sores may be caused by some serious underlying diseases. Such cases require proper medical treatment and management.

Physical trauma

Physical trauma to the lips is a very common cause of lip sores. It can happen to anybody. The trauma to the lips can occur in a variety of conditions, such as eating hot foods, drinking hot beverages, biting the lips, and picking the skin off the lips. Injury to the lips can also occur due to vigorous brushing of teeth, ill-fitting braces or dentures, and flossing. Scabs may form at the injured and bleeding sites on the lips. Infections may also develop at the sites of injury on the lips.

Dryness of lips

Dry lips are also a frequent occurrence, especially in dry or cold climates. The moisture on the surface of the lips evaporates quickly in dry, cold, or windy conditions. Other causes of dry lips include mouth breathing, dehydration, and repetitive licking of the lips. The lips are prone to getting dry easily, which also makes them susceptible to physical trauma. Lip sores can occur on dry lips that get injured.


Saliva is a natural secretion inside the mouth. It helps in preventing dryness of the mouth. However, saliva on the lips has the opposite effect. It tends to dry out the lips quickly. When the lips become a bit dry, there is a tendency to lick the lips frequently to moisten it. However, this worsens the dryness of the lips. Saliva can also cause skin irritation when present on the lips for a long period of time. This can lead to the development of lip sores in some cases.


Cosmetic applications (such as lipsticks) can irritate the skin on the lips. In individuals who are hypersensitive to the chemicals present in lip cosmetics, application of such cosmetics can cause allergic contact dermatitis. Even without any allergic reaction, application of lip cosmetics can cause irritant contact dermatitis in any individual. These conditions can further lead to the formation of lip sores.


Lip sores can also occur due to a variety of infections affecting the skin on the lips. These infections could be caused by different microbes, including bacteria, viruses and yeasts. Yeast infection of the lips is, however, rare. A common example of lip sores caused by an infection is the cold sore (also known as the fever blister). Cold sores are caused by an infection with the herpes simplex virus (type 1). This viral infection is contagious, and spreads very easily through acts such as kissing. Lip sores can also be caused by herpes simplex virus (type 2), also known as the genital herpes.

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Sunburns can occur on any exposed part of the skin. The skin on the lips is thinner than the skin elsewhere on the body. This makes them susceptible to sunburns. A sunburn on the lips is not always noticeable. The condition is characterized by an acute inflammation of the lip region. Even though sunburns are caused mainly through exposure to UV light present in the sunlight, there are other sources of UV light that are also capable of eliciting an inflammatory reaction in the lips. Tanning booths, for example, are another source of strong UV light that can cause sunburns.

Skin diseases

Skin diseases that can cause lip sores encompass a variety of different conditions, such as autoimmune diseases, contact dermatitis, allergies, and infections. In some cases, the exact cause of inflammation in the lip region may not be identifiable. Some skin diseases (such as psoriasis and atopic dermatitis) may spread to the lip region from other areas of the skin.

Angular cheilitis

Angular cheilitis is an inflammatory condition that is characterized by the presence of cracks and sores at the corners of the mouth. This condition can be caused by nutritional deficiencies, trauma, celiac disease, infections, skin diseases, and inflammatory bowel disease. Intake of certain drugs may also cause angular cheilitis. Severe cases of angular cheilitis may be characterized by bleeding from the sores present at the corners of the mouth. The skin in this area may also turn darker than the rest of the adjacent skin.

Nutritional deficiency

Lip sores can also occur due to certain nutrient deficiencies. The most common nutritional deficiencies that result in lip sores involve lack of sufficient iron and B vitamins (folate, vitamin B2, and vitamin B12). Chronic fasting, dieting, starvation, and malnutrition are typical causes of lip sores caused by nutritional deficiencies.


Lip sores can occur as a side-effect of taking certain medications. For example, isotretinoin (commonly used to treat acne) and acitretin (commonly used to treat psoriasis) are two drugs which are known to cause lip sores.

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