Several conditions in the mouth may cause inflammation. Canker sores resulting from a lip or cheek abrasion, stress, nutritional deficiencies, an impaired immune system or localized mouth burns often contribute to general oral inflammation.
Viral conditions such as herpes simplex or herpes zoster (shingles) can also cause swelling and blisters, while fungal infections such as oral thrush can irritate mouth tissue as well. Even a rare but mild allergic reaction to toothpaste can cause redness and sores.
Patients undergoing chemotherapy and radiation, patients who smoke cigarettes or chew tobacco and patients with other systemic diseases or injuries to the mouth can also experience any or all of the five symptoms of inflammation. Vaping and using e-cigarettes, seen by some as a safer alternative to smoking, can still cause dry mouth and oral chemical burns, says Dentistry iQ.