The common types of mouth infection
Infections in the mouth fall into three groups. Fungal infection is mostly oral thrush: creamy white patches that leave a red, sore base when wiped. Viral infections include herpes simplex and hand, foot and mouth disease, which cause painful blisters that burst into ulcers. Bacterial infections include gum infections and a dental abscess, where a tooth or the gum around it is infected.
Each has a different cause, so each needs a different approach. Thrush is common in people who use steroid inhalers, wear dentures, have diabetes or have recently taken a course of antibiotics. Viral sores usually settle by themselves. Bacterial infections of a tooth or gum need a dentist, because the source is dental.
| Infection | Usual cause | What it looks like | Usual approach |
|---|---|---|---|
| Oral thrush | Fungus | White or cream patches, red and sore underneath | Needs a doctor or dentist to confirm and treat |
| Herpes sores | Virus | Clusters of small blisters that become ulcers | Usually settles by itself; see our herpetic ulcer guide |
| Hand, foot and mouth disease | Virus | Ulcers in the mouth with rash on hands and feet, mostly in children | Rest, fluids, pain relief from a clinician or label |
| Gum infection | Bacteria | Red, swollen, bleeding or painful gum, bad taste | Dental examination and cleaning |
| Dental abscess | Bacteria | Throbbing pain, a swelling or pimple on the gum, sometimes face swelling | Needs a dentist promptly |
General guide to common mouth infections. It does not replace an examination.
Signs that point to infection rather than an ordinary ulcer
A single small round ulcer that heals in two weeks is usually not an infection; it is likely aphthous, as explained in our guide on stomatitis. Think infection when there are several sores at once, white patches, a bad taste or pus, pain in a tooth or gum, fever, or swollen glands in the neck.
Tongue changes are often part of the picture. Our guide on tongue infection covers what a coated, sore or discoloured tongue can mean, and herpetic ulcers in the mouth covers the viral blisters in detail.
When a mouth infection is urgent
Seek care the same day if you have swelling of the face or jaw that is spreading, or fever with mouth or tooth pain. Our page on face swelling due to tooth infection explains why this is the dental problem most likely to become serious.
Go to a hospital emergency department straight away if the swelling is spreading under the jaw or into the neck, or if you have difficulty swallowing or breathing. Do not wait for it to settle on its own.
A doctor or dentist prescribes antibiotics when a bacterial infection is spreading. They do not treat thrush or viral sores, and taking leftover tablets on your own delays proper care.
Looking after your mouth while you get seen
Keep brushing gently, rinse with warm salt water, drink plenty of fluids and avoid tobacco, gutkha and alcohol, which irritate an infected mouth and slow healing. Eat soft, cool food. Paracetamol or ibuprofen as directed on the label can ease pain; ask a pharmacist or doctor first if you have stomach, kidney or liver problems.
Any patch or sore that has not gone within three weeks needs examining, whatever the cause. See the mouth ulcers page for the full list of warning signs.
Common questions
How do I know if I have a mouth infection?
Pain, redness, white patches, several sores at once, pus, a bad taste or fever suggest infection rather than a simple ulcer. A dentist or doctor can tell which type it is by examining the mouth.
Can a mouth infection go away on its own?
Viral sores often do, usually within one to two weeks. Thrush and bacterial infections of a tooth or gum generally do not, and need treatment from a dentist or doctor.
Are mouth infections contagious?
Some are. Herpes sores and hand, foot and mouth disease spread through close contact and shared utensils. Aphthous ulcers and most dental infections are not passed on that way.
Do I need antibiotics for a mouth infection?
Not necessarily. They treat bacterial infections only, not thrush or viral sores. A dentist or doctor prescribes them when the infection is bacterial and spreading, so do not start them on your own.
About this page
This page is general information, not a diagnosis or a quotation. Prices are prevailing Lucknow market ranges. Your own treatment and cost are determined after an examination. For questions about your own case, call +91 83036 12717.