What this means
Muzzle swelling can be obvious, such as one cheek puffed out, or subtle, where the face simply looks different from usual. Compare the two sides of the muzzle and see whether the swelling is symmetrical.
How quickly it appeared matters a great deal. Swelling that builds within minutes or hours, especially with itching, hives or vomiting, can be an allergic reaction and needs urgent help. A slowly growing swelling on one side can be related to a tooth or another change in the mouth.
If your dog allows it, look into the mouth: is there a red gum, a broken tooth, a wound or a foreign object? Note whether your dog eats, can open its mouth wide, and reacts to pain on touch.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your dog.
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An allergic reaction
After an insect sting or contact with an allergen the muzzle can swell quickly. Itching, hives or vomiting may come with it.
About the condition: Allergies (food, skin and environmental) -
A tooth abscess or dental disease
An infected tooth root can swell the cheek or jaw on one side. Your dog may avoid chewing and guard its muzzle.
About the condition: Dental and gum disease -
A growth in the mouth or face
A growth may show as a slowly enlarging lump or a gradually growing swelling. The mouth may also bleed or smell unpleasant.
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Inflamed chewing muscles
Inflammation can swell the muscles, or later shrink them around the eyes and jaw. Your dog may struggle to open its mouth.
About the condition: Masticatory muscle myositis -
An injury or a bite
A blow, a bite from another animal or a foreign object can cause local swelling. A wound or bruise is sometimes visible.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- How quickly the swelling appeared and whether it is growing
- Whether one side is swollen or both
- Whether your dog eats and can open its mouth wide
- Whether a tooth, wound or foreign object is visible in the mouth
- Whether your dog is scratching or hives have appeared
- Whether the swelling is painful or warm
When to book a routine visit
Book a visit if the swelling lasts more than a day, grows slowly, or your dog avoids eating. If the swelling appeared suddenly, breathing has become harder or your dog cannot open its mouth, go straight away.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Dental and gum disease Digestion and liver Dental and gum disease starts with plaque that hardens over time into tartar, and the bacteria multiplying beneath it cause inflammation of the gums. Left alone, the inflammation can damage the tissues and bone that hold the tooth in place, so teeth loosen and fall out. A sore mouth troubles a dog every day, and infection in the mouth can affect other organs too.
- Allergies (food, skin and environmental) Skin and coat An allergy is an overreaction of the immune system to substances that are essentially harmless, such as pollen, house dust mites, moulds, flea saliva or an ingredient in food. In dogs it shows up mainly in the skin and ears, and constant itching wears a dog down and can open the way to skin infections. More than one trigger can be involved at once, so finding the cause takes patience.
- Cancer Cancer Cancer is not one disease but a whole group of different malignant tumours that can appear in almost any organ or tissue. They can grow slowly or quickly and spread to other parts of the body, so the earlier a change is noticed, the more options a vet has. Only a vet can tell whether a lump or other change is malignant.
- Masticatory muscle myositis Nerves and muscles Masticatory muscle myositis is an autoimmune disease in which a dog's immune system attacks the chewing muscles on the head. The inflamed muscles are painful and swollen, and over time they can waste away and stiffen, making it harder and harder for the dog to open its mouth. The sooner a vet sees the dog, the better the chance of keeping the jaw moving.
Body systems: Digestion and liver Skin and coat Cancer Nerves and muscles