The corners of my mouth are cracking up

1) Hi Alice,

Just wanted to know if you knew what the little sores were that come right in the corner of your mouth on the outside, not inside. I've heard they are caused by something lacking in your diet. Right now I have two, one on each side, and I have no idea what has changed in my diet to cause them. Is there anyway to clear them up?


2) Alice,

My friend has been experiencing cracked skin at the corners of her mouth for about a week now. I seem to remember my mother having the same thing, and that the cause was a deficiency or reaction of some kind. What could be the cause and does it have a name? She would like to do some self-educating before going to see her doctor.


Dear Dana and sd,

Cracks or sores in the corner of the mouth can be rather annoying at best and very painful at worst. These cracks or sores could be caused by any number of conditions, the four most common of which are angular cheilitis, cold sores, canker sores, and oral thrush. While these conditions may seem similar, they each have different causes and treatments. Getting a medical professional's perspective about your cases can help you determine what you're experiencing and what treatment, if any, is appropriate.

Angular cheilitis is actually an inflammatory condition and can cause bleeding and ulceration in addition to the painful cracks or sores. It usually lasts at least two to three weeks but can be longer. There is no universal cause for angular cheilitis, and the cracks develop due to a pooling of saliva in that area of the mouth, which creates an environment conducive to fungal or bacterial infection, such as staphylococcal infection. It can also be associated with oral thrush (more on this in a bit). People of all ages and sexes are susceptible to angular cheiltis.

Another possible cause of the sore on your mouths are cold sores. Also called fever blisters, they're caused by a latent herpes simplex virus that is activated through one of a number of routes, such as stress, sun exposure, or changes in hormone levels. Pain and itching may begin before the sores appear, followed by a red area forming on the lips. Eventually, this turns into a large red blister, swells, then bursts, leaving a scab to form. This process takes about two to three weeks in total, with the scab lasting from seven to ten days. More than half of the U.S. population has been infected by the time they reach their 20s. Cold sores are the only of the four listed here that is contagious, so be careful if you think you have a cold sore not to touch it then touch another person’s mucous membranes.

Different from cold sores, canker sores, also known as mouth ulcers, are caused by an altered immune response in that area due to stress, trauma, or irritation. For some people, this irritation can be caused by food with high acidity. Canker sores are small, shallow ulcers that are usually red or white in color. They occur on the inside of the mouth, near the lips, in the cheeks, or under the tongue, and last between five and ten days. These are most common in 16 to 25-year-olds, with 80 percent of women aged 10 to 20 experiencing them.

Oral thrush, scientifically known as oral candidiasis, is a yeast infection, caused by an overgrowth of the naturally occurring yeast that accumulates on the lining of the mouth. Oral thrush usually looks like white or pale yellow spots on the inside of the throat and mouth, somewhat like small cottage cheese curds. This can be accompanied by areas in the mouth that bleed, a loss of taste, a cottony feeling in the mouth, or redness and soreness that is bad enough to make swallowing difficult. Oral thrush usually occurs in the very young or old, in those who are already suffering from another disease or compromised immune system, in people with poor nutrition, or in those who take birth control pills or are pregnant.

Because of the many potential causes and conditions, treatment varies. For example, oral thrush may be treated with antifungal medication while canker sores may be treated with corticosteroids. On the other hand, cold sores generally go away on their own, but treatment can include an antiviral medication to speed up recovery. Your health care provider can give you more information, determine what's causing the cracks on your mouth, and recommend the appropriate treatment. If you continue to have problems with cracking at the corners of your mouth, they may be able to recommend some preventative measures you can take, such as avoiding certain foods or looking into ways to feel less stressed. After all, mouth health is all it’s cracked up to be!

Last updated Jun 29, 2018
Originally published Jun 07, 2002

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