Mouth Sores

Maintain good oral health

Mouth sores, also known as oral mucositis, are small cuts or sores that form in the mucosa, which is the lining of the inside of your mouth. Mouth sores can affect your gums, tongue, roof of the mouth and/or lips. They often begin as areas of mild pain or burning and develop into white patches that may become large red lesions.

Severe mouth sores can make it difficult to talk, eat or swallow, and the pain can have far-reaching effects on your nutritional status when the discomfort prevents you from eating. If the results are life-threatening, you may require a feeding tube. Also, an infection may develop if bacteria enter the open sores. For these reasons, it’s important to openly discuss mouth sores with your doctor.

What causes mouth sores?

The cells of the mucosa divide rapidly, as do cancer cells. So when chemotherapy and radiation are administered to attack cancer cells, they may also attack the cells of the mucous membrane and lead to mouth sores.

Who is at risk for mouth sores?

Mouth sores are most likely to occur in people treated with radiation to the head and neck area or who receive certain chemotherapy drugs. People who receive high-dose chemotherapy with a bone marrow transplant are also at high risk for mouth sores.

When do mouth sores occur?

Chemotherapy-related mouth sores usually develop within a few days after treatment begins and heal within two to four weeks after chemotherapy ends. Mouth sores caused by radiation usually develop two to three weeks after the start of treatment, and it may take four to six weeks for them to heal.

How are mouth sores managed?

The best way to manage mouth sores is to prevent them from developing. Taking good care of your teeth and gums is essential, so you should brush your teeth and floss several times a day. If you’ll be receiving chemotherapy, you may also want to suck on ice chips during the first half-hour of your treatment. This will reduce the likelihood of mouth sores because the cold limits the amount of the drug that reaches your mouth.

If mouth sores do develop, your doctor may suggest rinsing your mouth with special solutions or prescribe a medication that coats the lining of your mouth. Topical pain medications are an option as well. Additional ways in which you can prevent and manage mouth sores are summarized in Table 1.

Table 1. Ways to prevent and manage mouth sores

Routine oral care
▪ Regularly remove and clean your dentures
▪ Check your mouth twice each day with a small flashlight and tongue blade
▪ Clean your mouth and teeth gently with a soft toothbrush, cotton swab or
  mouth swab
▪ Rinse your mouth with salt or baking soda
▪ Use gentle mouthwashes regularly; your doctor will let you know which ones
  are good for you
▪ Keep your lips moist with K-Y jelly or lip balm; do not use Vaseline
Pain relief
▪ Suck on ice chips
▪ Apply topical, local anesthetic solutions or jellies, such as lidocaine
▪ Use oral analgesia or intravenous analgesia with opioids as prescribed by
  your doctor
▪ Rinse with medicated mouthwashes (dexamethasone, nystatin) to decrease
  inflammation and yeast infections
▪ Use topical corticosteroids (dexamethasone solution, triamcinolone 0.1
  percent in Orabase) on irritated areas on the tongue, mouth or lips
Dietary habits
▪ Drink a large amount of fluids (aim for two to three quarts per day) and use a
  straw to avoid irritating mouth sores while drinking
▪ Eat soft and/or semi-liquid foods; liquid supplements such as Boost and
  Ensure can also be used
▪ Eat high-protein and high-calorie foods so you don’t have to eat as much
▪ Eat foods at room temperature or slightly warm
▪ Do not eat hot, spicy, greasy, fried, coarse or rough-textured foods
▪ Do not consume very hot or very cold beverages and foods
▪ Steer clear of citric juices or foods containing acid, such as tomatoes, oranges
  and lemons
▪ Avoid all alcoholic beverages and tobacco products
▪ Do not use liquid medications containing alcohol, such as some cough
  medicines, if they are not essential

When should I talk to my doctor about mouth sores?

Talk to your doctor about the risk of mouth sores for the type of treatment you’ll receive. Call your doctor when you first notice any type of sore in your mouth. The sooner you treat mouth sores, the better chance you have of preventing them from becoming severe.


Medications associated with mouth sores
aldesleukin (Proleukin) epirubicin (Ellence) mitomycin (Mitosol)
alemtuzumab (Campath) etoposide (Etopophos) mitoxantrone
asparaginase (Elspar) everolimus (Afinitor, Zortress) oxaliplatin (Eloxatin)
busulfan (Busulfex, Myleran) fluorouracil (Carac, Efudex, Fluoroplex) paclitaxel (Abraxane, Taxol)
capecitabine (Xeloda) gemcitabine (Gemzar) pentostatin (Nipent)
carboplatin hydroxyurea (Droxia, Hydrea) procarbazine (Matulane)
cetuximab (Erbitux) idarubicin (Idamycin) thiotepa
cyclophosphamide (Cytoxan) irinotecan (Camptosar) topotecan (Hycamtin)
cytarabine (Cytosar-U, DepoCyt) lomustine (CeeNU) vinblastine
daunorubicin (Cerubidine, DaunoXome) mechlorethamine (Mustargen, Valchlor) vincristine (Marqibo)
docetaxel (Docefrez, Taxotere) melphalan (Alkeran)  
doxorubicin (Doxil) methotrexate (Otrexup, Trexall)  

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