Canker sores

Canker sores are small, recurrent, painful ulcers that may develop inside the lips or cheeks, underneath the tongue, or on the soft palate (the back part of the roof of the mouth). Canker sores don't develop on immovable surfaces of the mouth, such as the gums or roof of the mouth.


Causes/associated factors
The cause of canker sores isn't clearly understood. Possible causes may include:
infections
factors related to your immune system
stress
hormonal changes
the use of certain medications
mouth trauma, often incurred from the use of toothpicks, biting the inside of your mouth or eating sharp foods, such as corn chips
allergies to foods, as well as food or cosmetic additives
lack of saliva
quitting tobacco
Sometimes, canker sores run in families. After the first outbreak, recurrences are expected.

It's easy to confuse canker sores with fever blisters, also known as cold sores. Unlike canker sores, fever blisters are caused by a virus. They're highly contagious and develop on the outside of the lips. Side effects of certain medications may also cause mouth sores that look similar to canker sores.


Signs/symptoms
Before you can see a canker sore, you may feel a tingling or burning sensation where the sore is developing. Then, a round, red, elevated area quickly develops into a shallow, white ulcer. Canker sores are usually extremely painful for up to 10 days. During this time, they may interfere with speech and chewing. Canker sores may develop alone or in clusters and can range in size from a pinhead to a quarter. Most canker sores heal on their own within two weeks.

Diagnosis
Most canker sores are diagnosed by their appearance. The doctor will ask questions about your medical history and do a physical exam. Because canker sores sometimes are the first sign of other medical problems, your doctor may do blood work or even take a biopsy (remove a tissue sample for further analysis) of any suspicious sores to help rule out other medical conditions.

Treatment
There's no cure for canker sores. However, there are steps you can take to help decrease the pain and speed healing. Treatment is most effective when started as soon as symptoms begin.
Various over-the-counter medications can help ease symptoms. Consult your pharmacist or doctor to help decide which would be best for you.

Your doctor may suggest certain over-the-counter liquid medications to be used as a mouthwash, such as milk of magnesia or diphenhydramine mixtures. Prescription solutions, such as those that contain lidocaine, may also help ease pain.

Your doctor may recommend antibiotics.

Amlexanox is a prescription medication that may be effective for some people. It comes in a paste and is applied directly to the canker sore.

Topical steroids may also be prescribed. In severe cases, they may be taken orally (by mouth) or injected directly into the canker sore.
While the canker sore is healing, avoid foods that cause discomfort, such as hot or spicy foods, citrus fruits and foods that require a lot of chewing. Instead, eat foods that are soft and bland. It may also be helpful to avoid hot beverages and sip fluids through a straw.


Complications
Complications are rare. If it's too painful to eat or drink, however, malnutrition or dehydration are possible. Consult your doctor if you have a severely painful mouth sore or one that doesn't heal within three weeks.

Pregnancy-specific information
Consult your doctor if you develop any type of mouth sore while you're pregnant -- especially before taking any type of medication (including nonprescription drugs).

Senior-specific information
Older adults often experience mouth changes because of medication side effects, dentures that fit poorly or certain medical conditions. Be sure to discuss any sores you have with your doctor to diagnose or rule out other medical problems. Also, show your doctor a list of your current medications to identify or rule out possible medication side effects.

Prevention
To prevent canker sores, avoid foods that irritate your mouth. Chew your food carefully, and avoid toothpicks and sharp foods that can cause mouth trauma. It also helps to practice good oral hygiene. Brush your teeth gently with a soft bristled toothbrush and make sure your dentures fit properly.