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Cancer and Mouth Sores

What to expect and what you can do

By , Caring.com senior editor
94% helpful

Why mouth sores develop

Mouth sores are one of the most common side effects of chemotherapy or radiation therapy of the head and neck area. Known to doctors as mucositis, they can actually occur anywhere in the mouth or throat and develop when the ultrasensitive tissue that lines the mouth and throat becomes inflamed.

A number of risk factors increase the chance that your parent will have do deal with chemo-related mouth sores while battling cancer. People who smoke or wear dentures are particularly at risk, and those who have a history of susceptibility to cold sores, canker sores, and gum infections tend to have more trouble with mouth sores than those who haven't struggled with these irritations in the past. Because alcohol is an irritant and dries mouth tissues, drinking can exacerbate mouth sores. If your parent has a low white blood cell count, this can contribute to mouth sores as well.

Chemo-related mouth sores tend to be episodic, appearing three to ten days after a chemo treatment. The first sign is a burning sensation in the mouth, and the ulcers appear soon afterward. These types of mouth sores usually clear up within a week or so, unless malnutrition slows recovery.

The best way to treat chemo mouth sores is to start supporting your parent's body to fight them off before they start.

Prevention strategies for cancer-related mouth sores

Underlying dental problems can cause infections that the body can't fight off while being treated for cancer. So, if possible, schedule a visit to the dentist for a cleaning and checkup before your parent begins chemo or radiation therapy, and have any cavities, gum disease, or other problems treated. If your parent wears dentures, have the dentist make sure they fit properly and aren't causing any abrasions or irritation.

Note: Such dental appointments can be a chicken-and-egg situation that you should discuss with your parent's doctor: If your parent already has low white cell counts or low platelet counts, the doctor may advise holding off on dental treatment to avoid bleeding or infection.

A few other things to keep in mind in terms of oral hygiene:

1) Your parent should brush often (four to five times a day), using the softest possible toothbrush.

2) Have your parent wet his or her toothbrush with warm water to soften it before brushing.

3) Switch to a foam toothbrush if even soft-bristle toothbrushes are too harsh.

4) Make sure the toothbrush is cleaned thoroughly between brushings; you might have your parent alternate between two toothbrushes, letting each dry thoroughly.

5) If toothpaste is irritating, mix up a paste of baking soda and warm water for your parent to use.

6) If any kind of toothbrushing is too painful, your parent can use cotton swabs or special dental swabs.

7) Remove mouthwash from the bathroom, since alcohol, peroxide, and other ingredients are highly irritating.

Other preventive strategies involve keeping the mouth tissues well hydrated. During chemo, it can help immensely if your parent chews on ice chips while undergoing infusion. Then, starting right afterward, help your parent rinse regularly with a saline mouthwash, a homemade baking soda mouthwash (a half teaspoon of salt and a half teaspoon of baking soda in a glass of warm water), or the prescription mouthwash chlorhexidine.

Treatment for cancer-related mouth sores

For many types of mouth sores, particularly those that develop after chemo, the primary treatment strategy is to support the body's immune system while the mucosal cells that line the mouth regenerate themselves. What you particularly don't want is for the irritation to turn into an infection; if that happens, you'll need to ask your parent's doctor for antibiotics.

You'll also want to help your parent avoid anything that contributes to the irritation, so make sure that food isn't too hot, and don't serve any spicy or acidic foods (absolutely no citrus-based fruit juices or tomato sauces) or anything with hard or sharp edges (nuts, crusty bread, apple slices) that could cut the mouth. Have your parent skip carbonated drinks like seltzer and soda, which are irritating, and suggest water instead.

There are many other ways to keep mouth irritation from getting out of control. These will be trial-and-error efforts; offer each one and see which helps the most.

  • Tea (use for gargling)
  • Honey (swallow undiluted or add to tea)
  • Cepacol lozenges
  • Chloraseptic spray and lozenges
  • Lip balm (not Vaseline) to keep lips moist
  • Water-soluble moisturizing jelly (K-Y) to moisturize mouth tissues
  • Milk of Magnesia or Mylanta (dilute in water for gargling)
  • Probiotic supplement rinses (which beneficial bacteria or yeast)
  • Papaya or papaya juice
  • Glutamine powder (mix with water and drink)

Pain relief for cancer-related mouth sores

Once mouth sores develop, they're very painful. They also interfere with eating, and cancer patients need to take in nutrients. While this may seem like a minor problem in the face of everything else that's going on, be proactive about pain relief so that sores don't contribute to loss of appetite and weight. Again, pain relief may be a process of trial and error. Some options:

  • Acetominophen, aspirin, and ibuprofen (choose based on other factors such as bleeding)
  • Oral Benadryl
  • Zinc lozenges
  • Orabase/Kenalog dental salve (cover sores several times a day for faster healing)
  • Lidocaine (brand name Xylocaine), an analgesic gel that stops pain temporarily
  • Kaopectate and Carafate (use straight, swishing around the mouth to decrease irritation)

It's also a good idea to offer pain relief immediately prior to meals, so your parent will be able to eat. Try a combination of an oral pain medication, such as acetominophen, half an hour before eating and an analgesic gel (lidocaine or benzocaine) just before meals. If your parent's sores are in the back of the mouth, throat, or esophagus and make swallowing difficult, ask the doctor for the jelly form of lidocaine or benzocaine, and have your parent gargle it right before meals. There's also a spray form for sores on the roof of the mouth and throat. Some doctors will even recommend swallowing analgesic jelly if getting food down is a serious issue.

If your parent can't eat much at one sitting, suggest six small meals a day instead of three big ones, and serve moist, soft foods. You can use liquid nutritional supplements to boost calories and nutrients if eating is just too hard.

When cancer-related mouth sores don't heal

Have your parent check his or her mouth daily for signs of infection. Yeast or fungal infections look like white spots, while bacterial infections appear red and inflamed. If you or your parent suspects a yeast or fungal infection, ask for a prescription rinse, tablet, or cream with an antifungal agent such as nystatin or clotrimazole. If herpes-type mouth sores start to develop, the antiviral acyclovir or a newer antiviral called valacyclovir (Valtrex) may help. If your parent's mouth sores become infected, the doctor will probably suggest a peroxide or chlorhexidine antibacterial mouth rinse. The doctor can also prescribe oral antibiotics, depending on the type of cancer treatment your parent is undergoing and other factors such as blood cell counts.

Cheo-related mouth sores are an unfortunate fact of life for many patients undergoing treatment for cancer, but staying on top of them and being proactive about prevention, treatment, and pain relief can stop them from causing loss of appetite and weight loss.