Expert: Frederick R. Liewehr DDS, MS, FICD - 2/10/2009

Question
Several years ago I had dental work done, and the day after I had many painful, small blisters in the area where the work was done. They lasted for a week or so. I assumed they were from the topical numbing agent or maybe the cinnamon flavoring. Since then I have a new dentist and he has not used the topical product, just the injection. He said he had never seen a reaction like I described. today I had a crown removed and tonight the blisters have appeared on the inside of my cheek. I do  not know what drug was used. From what I have read, this may be an allergy to a preservative or vasoconstrictor? I will call the dentist in the morning to discuss this. Do you have any insights as to what the problem is? I do have allergy to sulfa (hives) and one time I had a severe, rapid (within 1 hour) reaction to a TB test that a doctor told me was not a positive TB test but was probably a reaction to a preservative. Thank You

Answer
The two possibilities that come to mind are apthous stomatitis and herpetic stomatitis.

Apthous ulcers commonly occur singly, but can occur in crops. When there are a lot of them, we call this major apthous stomatitis. These are commonly known as canker sores, and occur at time of stress (like your dental treatment). They can be quite painful, last 10-14 days, and spontaneously regress. These lesions are ususally found on the mucosa, the movable tissue in your mouth.

Recurrent herpes stomatitis is similar, but usually occurs on the gingiva, or harder, bound-down tissue in your mouth, such as your hard palate. These lesions are usually not quite as painful, and last 5-7 days.

In either case, there is not a lot you can do to prevent them or to help them to get better. Usually a palliative mouth rinse is about all that is available. Ask your dentist about this.