Viral infections
- Herpangina: common in young children, with sudden fever, sore throat and small grey-white blisters on the soft palate and tonsils that become ulcers.
- Hand, foot and mouth disease: mouth and throat ulcers with spots on the hands and feet.
- Herpes simplex: first infection in children can cause many mouth and throat ulcers with fever.
- Glandular fever: very sore throat, swollen tonsils, swollen glands and tiredness.
- Colds and flu: can cause small ulcers and irritation.
These usually heal within 7 to 10 days. See throat infection.
Canker sores in the throat
Aphthous ulcers are round, white or yellow sores with a red border. They often appear inside the cheeks and lips but can occur on the soft palate and around the tonsils, where they are very painful when swallowing. Stress, minor injury, hormonal changes and some foods may trigger them. Recurrent ulcers can be linked to iron, B12 or folate deficiency, coeliac disease or inflammatory bowel disease.
See roof of mouth pain.
Bacterial infections
Tonsillitis and strep throat can cause white patches on the tonsils that may look like ulcers. Rarely, other infections, including syphilis and fungal infections in people with weakened immune systems, cause throat ulcers.
See white spots on tonsils and strep throat.
Reflux and the oesophagus
Stomach acid can inflame and ulcerate the lower oesophagus, causing burning chest pain, pain on swallowing and a sour taste. Laryngopharyngeal reflux irritates the throat and voice box, with throat clearing, hoarseness and a lump sensation.
See acid reflux sore throat and lump in throat.
Medicines and injuries
- Some tablets, such as anti-inflammatories, certain antibiotics, iron and bisphosphonates, can cause ulcers if they get stuck in the oesophagus; take them with a full glass of water and stay upright.
- Chemotherapy and radiotherapy to the head and neck cause painful mucositis.
- Burns from hot food or drinks.
- Scratches from sharp foods or fish bones.
- Injury from medical procedures, such as a breathing tube.
Less common but important causes
An ulcer in the throat or tonsil area that does not heal, especially on one side, in a smoker or heavy drinker, or with a lump in the neck, ear pain on the same side, weight loss or difficulty swallowing, may be a sign of throat cancer and needs prompt ENT assessment. Autoimmune conditions such as Behçet’s disease can also cause recurrent ulcers.
How to ease the pain
- Drink plenty of cool fluids; ice lollies help children.
- Eat soft, cool foods: yoghurt, smoothies, porridge, mashed potatoes.
- Avoid spicy, acidic, salty, crunchy and very hot foods.
- Gargle with warm salt water (adults and older children).
- Use pain-relieving sprays, lozenges or gels from a pharmacy.
- Take paracetamol or ibuprofen if suitable.
Throat ulcers in children
Young children with herpangina or hand, foot and mouth disease may refuse to eat or drink because swallowing hurts. The main risk is dehydration: offer small, frequent drinks and give pain relief before meals. Seek advice if a child has fewer wet nappies, is very sleepy, or cannot drink.
How throat ulcers are assessed
A doctor or ENT specialist examines the mouth and throat and may use a small flexible camera to see deeper areas. Swabs, blood tests and, for persistent ulcers, a biopsy may be done. An endoscopy examines the oesophagus when reflux or medicine-related ulcers are suspected.
Reducing the risk of throat ulcers
- Wash hands often to reduce viral infections, especially around young children.
- Take tablets with a full glass of water and stay upright for 30 minutes.
- Let hot food and drinks cool before eating.
- Manage reflux with diet and lifestyle changes.
- Stop smoking and limit alcohol.
When to see a doctor
- Difficulty breathing, drooling or inability to swallow.
- Signs of dehydration.
- High fever or a very unwell child.
- An ulcer lasting more than 3 weeks.
- Weight loss, a lump in the neck, ear pain or hoarseness lasting more than 3 weeks.
- Frequent recurrent ulcers.
Key points to remember
- Viral infections are the most common cause of throat blisters and ulcers.
- Canker sores, reflux, medicines and injuries are other causes.
- Cool soft foods, fluids, gargles and painkillers help.
- Ulcers lasting more than 3 weeks need checking.
Questions about throat ulcers
These answers are general information and do not replace an examination or individual medical advice.
What causes blisters at the back of the throat?
Viral infections such as herpangina and hand, foot and mouth disease are common causes.
How long do throat ulcers last?
Most heal within 1 to 2 weeks.
Are throat ulcers contagious?
Viral ulcers can be; canker sores are not.
Can stress cause ulcers in the throat?
Stress can trigger canker sores, including in the throat area.
Can acid reflux cause throat ulcers?
Yes, especially in the oesophagus.
What can I eat with a throat ulcer?
Cool, soft foods such as yoghurt, smoothies and porridge.
When is a throat ulcer serious?
If it lasts more than 3 weeks, is one-sided in a smoker, or comes with weight loss or a neck lump.
Sources
This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.