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What are Different Types of Mouth Sores?

Henry Gaudet
Henry Gaudet

Various types of mouth sores can appear in or around the mouth for a number of reasons. Injuries to the mouth, such as a bite to the inside of the cheek, are common sources. Chemical or allergic irritation can cause blisters and ulcers to form, and cold sores or fever blisters will form as the result of a viral infection. The causes of one type, called canker sores, are not fully understood, but they are believed to be related to the immune system. Many other conditions can trigger sores in the mouth as well, but these are some of the most common.

Injury is perhaps the simplest cause for mouth sores; a cut or scrape to the inside of the mouth causes injury in the form of an ulcer or blister. Blistered, fluid-filled sores in the mouth are referred to as vesicles or bullae, depending on the sore’s size. Chemical burns and allergic reactions to food or medications also can create sores. They often are quite painful, especially when eating salty or acidic foods, until they've had a chance to heal.

Cold sores and fever blisters are caused by viral infection.
Cold sores and fever blisters are caused by viral infection.

Viral infection is a common cause of mouth sores. The familiar cold sores and fever blisters are caused by herpes simplex virus (HSV) type I and are highly contagious, often passed on through contact with infected skin or saliva. HSV infections are perhaps the best known source, but other viral, fungal and bacterial infections, such as syphilis and herpes zoster, the virus that causes chicken pox and shingles, also can trigger blisters and ulcers in and around the mouth. Bacterial infections of the teeth or gums can cause an abscess or cellulitis and are potentially serious.

Canker sores are not contagious.
Canker sores are not contagious.

Canker sores, also known as aphthous stomatitis, are another very common type of sore in the mouth. These recurring sores are not contagious and seem to be triggered by an immune system reaction, although the actual cause is unknown. Canker sores form as oval ulcers with a white center. They are painful, but usually disappear within two weeks without complication. Larger sores, however, can take longer to heal and can cause scarring.

Salty or acidic foods may be painful to eat with a mouth sore.
Salty or acidic foods may be painful to eat with a mouth sore.

Treatment for mouth sores varies depending on the cause, but many require only time to heal. An anesthetic mouthwash or lozenge might help reduce the pain. The entire mouth should also be cleaned frequently with a soft toothbrush to help prevent infection. Treatment with medicated gels, chemicals, or laser treatments might also be recommended by a medical professional.

Discussion Comments


I was eating nachos and eating with the first chip it got stuck on the top of my gums, and was really hot. I couldn't get it off and had to shove my finger in to get the chip out of my mouth.

Now in one spot I have a really soft spot, and my whole top gum burns. I don't know what the soft spot is, and my grandmother thinks it's a sore or something, but this doesn't seem right.


I went to a dentist to get a bad tooth pulled, and he tells me that I have two bad problems that needed taken care right now. He did a root canal and pulled a tooth that was infected. I was in so much pain for four days, then went back to get a cap put on the root canal tooth, telling him that I am in pain from the tooth that he pulled clear up to my head.

He had a look then finished the cap on the tooth, then informed me that I have a viral blister on the top of my mouth where he had been working, then told me that it was common, and that it was due to trauma from him working on my mouth. He also said that I was very contagious to others. I have never heard of such, nor have I ever had this problem before.

What I want to know is could I have gotten this problem form his office from not so clean tools? I am so upset, and this has hurt my relationship with my roommate and my bosses.


I have a sore on the back right side of my tongue that makes it nearly impossible to eat because it hurts so much! It even hurts to drink water and spit!


@JessicaLynn – I have heard that brushing your teeth with a toothpaste that doesn't contain sodium lauryl sulfate can help prevent canker sores. My mom says that it works for her.

I get canker sores every now and then, and it usually happens after I bite myself while chewing. So, they are always on the insides of my cheeks somewhere.

I've tried the salt water rinse, and it makes them heal faster. Nothing can get rid of them right away, though. They really take the fun out of eating Mexican food, because a lot of it will really burn them badly!


My most common mouth sores are fever blisters. I can feel part of my lip getting hot and itchy before the blister forms, and if I react quickly enough, sometimes I can head it off.

As soon as I feel the abnormal warmth and itchiness, I put medicated lip balm on the area. Though it is often used to numb the pain of fever blisters, it can also work to prevent them. I keep a tube in my purse at all times, because I never know when one is going to pop up.


I get mouth sores on my tongue whenever I eat too much sour hard candy. It really irritates my tongue, and I can feel the soreness for the next day or two.

During this time, I have to avoid tomatoes, orange juice, and pineapple. They make my tongue burn badly.


@strawCake - Luckily there are a lot of over the counter cold sore products around. You should try one out next time you get a cold sore so you can speed up the healing process.

My most unpleasant mouth sore experience was when I had braces as a middle schooler. Once my dentist didn't cut the end of the wire that ran through the braces well enough. I didn't realize it til the evening when they were already closed! I developed a sore from irritation on my check behind my molar. As if having braces wasn't bad enough!


@JessicaLynn - I get canker sores occasionally also. They are annoying!

I also get cold sores every now and then. Those are extra unpleasant, because people can actually see them. I know a lot of people make a huge deal about cold sores because they're cause by *gasp* the herpes virus. But they are so common!

I actually read somewhere that 80% of adults carry HSV type I by the time they're 50. Since it's so common, I don't know people get so upset about. However, people really, really do.

I had a friend who's boyfriend actually broke up with her because she had a cold sore. He thought it meant she had genital herpes too, and nothing she said could convince him otherwise!


I get canker sores fairly frequently. It makes sense that they would be related to the immune system, because I also get sick a lot! It sounds like I need to do something to strengthen my immune system so I stop having these problems.

Anyway, canker sores are quite annoying and definitely painful. Usually when I get one, I try a trick my mom showed me and it tends to speed up the healing process. I rinse my mouth out with salt water. I have no idea why this works, but it definitely does. I assume it would probably work for other kinds of mouth sores too.

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    • Cold sores and fever blisters are caused by viral infection.
      By: uwimages
      Cold sores and fever blisters are caused by viral infection.
    • Canker sores are not contagious.
      By: Antonio Gravante
      Canker sores are not contagious.
    • Salty or acidic foods may be painful to eat with a mouth sore.
      By: Whitebox Media
      Salty or acidic foods may be painful to eat with a mouth sore.
    • Treatment for mouth sores ranges from using anesthetic mouthwash to chemical and laser procedures.
      By: ijacky
      Treatment for mouth sores ranges from using anesthetic mouthwash to chemical and laser procedures.
    • A herpes sore.
      A herpes sore.
    • Ice chips can take down the swelling of mouth sores.
      By: Silkstock
      Ice chips can take down the swelling of mouth sores.