Mouth
Swollen tongue or lips
Swelling of the tongue, lips or mouth that can be a harmless reaction or a sign of an allergic-type reaction, an infection or a deficiency — but which, when it comes with difficulty breathing or swallowing, is a life-threatening emergency.
Education and reference only. This explains the common causes of swollen tongue or lips and the warning signs that need urgent help, in plain language — it is not a diagnosis or a substitute for advice from a clinician. If you feel very unwell or are worried, seek medical help.
Quick answer
What is swollen tongue or lips?
A swollen tongue or lips can range from a minor, gradual change to a sudden, frightening swelling that threatens the airway, so the speed of onset and the company it keeps matter enormously. Sudden swelling of the tongue, lips, mouth or throat — especially after a food, an insect sting or starting a new medicine, and particularly if it comes with a widespread rash, wheeze, dizziness or trouble breathing or swallowing — is a severe allergic reaction called anaphylaxis and is a 999 emergency.
- Get urgent help: Call 999 now if there is swelling of the tongue, lips, mouth or throat with any difficulty breathing, swallowing, a tight throat or a hoarse or muffled voice — this may be anaphylaxis. Call 999 if swelling comes on suddenly with a widespread rash, wheeze, dizziness, faintness or a feeling of impending doom.
- Self-care: Once a clinician has confirmed that a swelling is not dangerous, the most important step is to avoid whatever triggered it: keep a note of any food, medicine, sting or product linked to the swelling and steer clear of it, and tell any clinician about a known allergy before starting anything new.
About swollen tongue or lips
A swollen tongue or lips can range from a minor, gradual change to a sudden, frightening swelling that threatens the airway, so the speed of onset and the company it keeps matter enormously. Sudden swelling of the tongue, lips, mouth or throat — especially after a food, an insect sting or starting a new medicine, and particularly if it comes with a widespread rash, wheeze, dizziness or trouble breathing or swallowing — is a severe allergic reaction called anaphylaxis and is a 999 emergency. Repeated episodes of deep swelling without an obvious trigger can come from a condition called angioedema. Slower or more persistent changes are usually less dangerous: a sore, swollen or smooth tongue can come from a deficiency such as low iron, while a coating, white patches or soreness can come from a yeast infection in the mouth, and an underactive thyroid can leave the tongue feeling enlarged. Any swelling that affects breathing or swallowing must be treated as an emergency until proven otherwise.
When to get help
Call 999 or go to A&E if swollen tongue or lips comes with any of these warning signs:
- Call 999 now if there is swelling of the tongue, lips, mouth or throat with any difficulty breathing, swallowing, a tight throat or a hoarse or muffled voice — this may be anaphylaxis.
- Call 999 if swelling comes on suddenly with a widespread rash, wheeze, dizziness, faintness or a feeling of impending doom.
- Seek urgent help for tongue or lip swelling that is rapidly getting worse, even if breathing still feels normal.
- Seek urgent help if swelling starts soon after a new medicine, a food, or an insect sting.
- See a doctor promptly for a persistently swollen, sore or smooth tongue that does not settle, as it may point to an infection or deficiency.
When to see a doctor
Any swelling of the tongue, lips or throat that affects breathing or swallowing, or that comes with a rash, wheeze or faintness, is an emergency — call 999 and do not wait to see if it settles. If you carry an adrenaline auto-injector for a known allergy, use it as you have been shown while help is on the way. For slower, milder swelling or a persistently sore tongue with no breathing problems, book a routine appointment so the cause — such as a deficiency, a mouth infection or a thyroid problem — can be confirmed and addressed.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
What can cause it
Common causes of swollen tongue or lips
Swollen tongue or lips has many possible causes. Each links to a full, plain-language guide to that condition — what it is, how it's treated and when to seek help.
What helps
Self-care and what you can do
Once a clinician has confirmed that a swelling is not dangerous, the most important step is to avoid whatever triggered it: keep a note of any food, medicine, sting or product linked to the swelling and steer clear of it, and tell any clinician about a known allergy before starting anything new. For a sore or coated tongue from a mouth infection or a deficiency, good mouth care helps — keep the mouth clean, stay well hydrated, and eat a varied diet. Cool drinks or a cold spoon held against the lips can soothe minor lip swelling. If you have ever had a serious allergic reaction and have been given an emergency device, carry it at all times and make sure those around you know how to use it.
Answers
Swollen tongue or lips: frequently asked questions
When is a swollen tongue an emergency?
Treat it as a 999 emergency whenever swelling of the tongue, lips, mouth or throat comes with any difficulty breathing or swallowing, a tight or hoarse throat, a widespread rash, wheeze or faintness. This combination can be anaphylaxis, which can be life-threatening within minutes.
What can cause my tongue to swell without an allergy?
A swollen or sore tongue can come from a yeast infection in the mouth, a deficiency such as low iron, or an underactive thyroid, and repeated deep swelling can come from a condition called angioedema. A clinician can work out which applies and whether tests are needed.
Can a medicine make my lips or tongue swell?
Yes. Some medicines can cause swelling of the lips, tongue or face, occasionally as part of a serious allergic reaction. Sudden swelling after starting a new medicine needs urgent assessment, and you should tell any clinician about it.
My tongue feels swollen and sore but looks normal — what now?
A tongue that feels swollen or sore without obvious swelling, especially if it is smooth or has cracks at the corners of the mouth, can point to a deficiency or a mouth infection. If there is no breathing or swallowing difficulty, book a routine appointment so the cause can be checked.
Sources
Where this is drawn from
- NICE CKS: Angioedema and anaphylaxis.
- British Society for Allergy and Clinical Immunology.
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