Lip ulcers are cold sores, and canker sores are a type of mouth ulcer. Both can cause pain and discomfort but typically clear up without medical treatment.

Lip ulcers are another name for cold sores. Caused by the herpes simplex virus type 1 (HSV-1), cold sores cause a burning or itching sensation as they develop. They are highly contagious.

Mouth ulcers, or canker sores, occur in the mucous membranes of the mouth. They can present in different ways and sizes and can be very painful. Doctors do not know what causes them, but they may have links to viral or bacterial infections, a weak immune system, genetics, or allergies.

This article looks at the symptoms, causes, diagnosis, and treatment of lip and mouth ulcers.

Learn more about all types of mouth ulcers here.

Lip and mouth ulcers are very different conditions and present in different ways.

Lip ulcer symptoms

People who experience lip ulcers will likely have a cold sore.

As a cold sore develops, a person will experience a burning, itching, throbbing, or tingling sensation. The fluid-filled sores that develop will dry out, forming a yellow crust within about 2 days.

Sometimes, a fever accompanies a cold sore, and some people call them fever blisters. Other symptoms may include a sore throat, a headache, or nausea.

The virus that causes cold sores remains in a person’s body forever, which means that cold sores may also recur throughout a person’s life. However, symptoms may be less severe each time the colds sores appear.

Some people get cold sores about five times per year.

Learn why cold sores keep coming back here.

Mouth ulcer symptoms

Mouth ulcers, or aphthous ulcers, are small, round, painful sores that can appear in and around the mouth. They are usually yellow, white, or gray in the center and may have a red ring surrounding them.

Canker sores may develop for many reasons. Although infections do not typically cause these mouth ulcers, they can develop when the body is fighting an infection elsewhere in the body or a person has a fever from something like the flu.

Different types of canker sores may present differently and recur more often. Larger, or major, canker sores are more painful.

There are three main types of canker sores:

  • Minor canker sores: These are the most common type, causing small sores that heal in around a week without scarring. They affect about 85% of people.
  • Major canker sores: Present in only about 10% of cases, these sores are larger than minor sores and last for over 2 weeks. The sores are very painful and can cause scarring.
  • Herpetiform canker sores This type affects fewer than 5% of people and causes clusters of tiny sores to develop, which take around a week to heal. They can recur quickly and may merge into one large ulcer, which can leave scarring.

Learn more about canker sores on the lip here.

Typically lip and mouth ulcers do not require treatment and will clear up on their own.

Lip ulcer treatment

According to a 2019 article, cold sores do not require treatment and go away on their own within a couple of weeks.

However, treatment is available to help speed up the healing process. A virus causes a cold sore, so treatment typically involves using antiviral medications. Some medications require a prescription, but many topical antiviral medications, such as patches, creams, lotions, or gels, are available over the counter.

Learn more about how to get rid of a cold sore here.

Mouth ulcer treatment

Most canker sores will heal in 1 to 2 weeks.

The sores can cause problems when a person is eating or talking due to friction and subsequent pain.

A doctor may suggest taking acetaminophen (Tylenol) for the pain. Other treatment options will focus on reducing inflammation, such as steroid mouth rinses or creams.

A topical anesthetic can numb the skin and reduce pain from the sore. Antimicrobial mouthwash can kill bacteria and other germs in the mouth. This lowers the risk of a sore on the lip becoming infected.

Learn about 9 ways to treat mouth ulcers here.

Mouth and lip ulcers can be uncomfortable and painful, so it is important to take care of them to prevent further pain and damage.

For people with a cold sore:

  • eating cool, soft foods
  • practicing good hygiene by washing your hands thoroughly after applying cream
  • using sunblock (SPF 15 or above) on lips when in the sun
  • taking paracetamol or ibuprofen to ease pain and swelling – do not give aspirin to children under 16

Anyone who touches a cold sore must wash their hands immediately; otherwise, it is possible to spread the virus to another part of the body or someone else.

For people with mouth ulcers:

  • practicing good oral hygiene, such as regularly using mouthwash and flossing, will help to reduce the risk of infections
  • avoiding irritating the sore by not touching the ulcer or not brushing teeth too vigorously
  • reducing friction by eating foods that do not require lots of chewing
  • avoiding spicy, salty, or acidic foods that can irritate the sore

Learn more about mouth sores and how to prevent them here.

Cold sores are highly contagious. A person can transmit the virus to another person through mouth-to-mouth or mouth-to-genital contact. Anyone with cold sores should take care to avoid this kind of contact while the symptoms are active.

Learn how long a cold sore is contagious for here.

However, canker sores are not contagious as they are not due to an infection. It is not possible to pass a canker sore to another person.

Cold sores or lip ulcers usually clear up within 2 weeks, but a person should speak to a doctor if they are experiencing recurrent cold sores or they are taking longer to heal.

People with eczema or weakened immune systems should take care as a cold sore could spread to larger areas of skin.

Many mouth sores will clear up on their own without treatment.

Contact a doctor if:

  • more than three outbreaks occur per month
  • the sores persist for weeks and do not improve
  • the pain is severe or worsens

If a person has a cold sore, they may develop an ulcer on the lip and present with other symptoms, including fever. Canker sores cause small, painful sores that develop on the mouth and gums and vary in size.

Mouth ulcers and cold sores usually clear up without treatment. Several creams, ointments, and mouthwashes can help alleviate symptoms.