Medical questions & health advice by board certified doctors

"How do cold sores and canker sores differ?"

ZocdocAnswersHow do cold sores and canker sores differ?


What is the difference between a cold sore and a canker sore? I get the kind which is like an ulcer inside my mouth ? mostly on my lips and cheeks. Are these caused by the herpes virus, too? If not ? what causes them?


Cold sores and canker sores are very common oral lesions that are experienced by a large number of individuals at some point in their lives. If you are experiencing oral or peri-oral lesions (meaning lesions around the mouth) you should see your primary care physician or a dermatologist for further evaluation, as these can be symptoms of a more serious illness. There are a number of illnesses which may cause oral lesions. The most common cause of oral lesions are canker sores, also called apthous ulcers. These are usually benign, last 1 - 2 weeks and do not leave a scar. They should resolve on their own, or your doctor may give you a steroid ointment to quicken healing. Your doctor may also try to help you identify triggers of aphthous ulcers, such as NSAID drugs (i.e. ibuprofen), certain foods, or stress. Aphthous ulcers are always located on the inside of the mouth, unlike herpes lesions (also known as cold sores) which are usually found on the lips around the mouth. Cold sores are caused by the herpes virus and are contagious, so you should not share drinks with people who have cold sores. If you get frequent aphthous ulcers or ulcers that do not go away, you should see your physician to make sure you do not have a more serious illness. Aphthous ulcers can be a symptom of both autoimmune disorders and a weak immune system. Similarly, recurrent herpes lesions may also be a sign of a weak immune system. The diagnosis and management of this condition will require a physical examination and evaluation by a licensed physician. If you have any concerns or would like to pursue treatment for these symptoms you should schedule a visit with your healthcare provider.

Zocdoc Answers is for general informational purposes only and is not a substitute for professional medical advice. If you think you may have a medical emergency, call your doctor (in the United States) 911 immediately. Always seek the advice of your doctor before starting or changing treatment. Medical professionals who provide responses to health-related questions are intended third party beneficiaries with certain rights under Zocdoc’s Terms of Service.