Health Topics for Skin Health

Department of Dermatology

Department of Internal Medicine: Allergy

Dermatological Cancers

Canker sores and fever blisters

Canker sores and fever blisters (or cold sores) are often confused because they both occur in the area of the mouth. Differences exist in appearance, causes, and specific locations. Most of the time, there is little that can be done for either one of them. They just run their course.

Canker sores are open sores on the tongue, gums, or inside the cheeks. They are painful and irritating. Canker sores usually heal in 7 to 10 days. Stress, biting your tongue or cheek, heredity, female hormones, and food allergies are all possible causes of canker sores. These sores may appear at any age, but usually appear for the first time between the ages of 10-20 years. Canker sores often run in families, but they are not contagious.

Try these self-care tips for treating canker sores:

• avoid spicy or salty foods, coffee, and citrus fruits
• apply ice to relieve the pain
• rinse your mouth with a mixture of one tablespoon of hydrogen peroxide in 8 ounces of water
• apply a thin paste of baking soda and water to the sore
• apply an oral paste to protect the sore, ease pain, and speed healing (examples are Orabase, and Zilactin-B)
• use a soft-bristle toothbrush and
• when canker sores continue to come back, or are so painful that it is difficult to eat or drink, see your healthcare provider who may treat the canker sores with a prescription mouthwash

Cold sores (or fever blisters) are tiny red blisters that are most likely to appear on your gums, outside your mouth and lips, or on your nose, or cheeks. Small blisters form, break, and ooze a clear fluid. A scab forms then comes off to uncover pink, healing skin. Cold sores also seem to run in families, but they are quite different than canker sores.

The contagious herpes simplex virus type 1 causes cold sores. The virus can be passed between people in saliva or by using contaminated eating utensils, towels, and shaving tools such as razors. Once one has had a cold sore, the virus stays under the skin waiting to be reactivated by colds, fever, fatigue, sunlight, stress, or menstruation. The sores last about a week or two and often recur in the same spot again and again. They often reappear during physical illness, emotional stress, or exposure to the sun.

Your provider may prescribe antiviral medication. This medication can shorten the duration of cold sores and speed the drying up of the blisters. It won't prevent recurrences.

Try these self-care tips for treating cold sores:

• wash hands frequently and after touching your mouth to prevent spreading the sores. (Be careful about touching other parts of your body. Eyes and the genital areas are particularly susceptible to the virus.)
• apply a local drying or soothing agent (such as Abreva, Debrox, or Blistex) 3 to 4 times a day (do not share these with others and follow the directions on the label)
• use over-the-counter pain medication or ice to relieve pain
• do not squeeze or pick the sores
• avoid kissing and skin contact with people while blisters are present
• avoid situations that trigger the cold sores such as cold and sun
• use sun block on your lips and face before prolonged sun exposure
• when the cold sores continue to come back, become more severe, or last for more than 7 to 10 days, see your provider who may treat the cold sores with prescription drugs

Also, be sure to contact your provider if you have a pre-existing condition that has compromised your immunity system.

Last Reviewd 2005

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

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