What this means
A fresh wound or a recently tended area may look a little crusted, slightly red and tender for the first few days. What raises concern is a change: the edges slowly thicken, the skin around becomes firm or hot to the touch, the wound grows instead of shrinking, or the dog guards it more and more and will not let it be touched. Heat is often noticed before redness, especially on dark or furred skin, so it helps to gently compare with the skin nearby.
The reasons for swelling vary a great deal. Sometimes it is inflammation or infection in the wound, sometimes fluid or blood has collected under the skin, sometimes a foreign body has got into the wound, and sometimes the dog is simply licking or scratching it and keeping it irritated. These cannot be told apart from the outside, so the wound should not be handled at home and should be shown to a vet.
To help your vet, photograph the wound each day at the same time from the same distance and note when you first saw the swelling and whether it is growing. Notice whether any fluid comes from the wound, what colour and smell it has, whether your dog has a fever and whether it is eating as usual. Say also how the wound came about: a cut, a bite, a graze or a recent procedure.
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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Inflammation or infection in the wound
Germs that get into a wound can make it hot, red and swollen. Pus or an unpleasant smell may appear as well.
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Fluid or blood collected under the skin
A soft or firm swelling can form at the wound when fluid or blood gathers under the skin. The dog may feel it and guard the spot.
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A foreign body left in the wound
A splinter, grass seed, thorn or bit of dirt can stop a wound from closing and cause inflammation.
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Constant licking or scratching
The dog's tongue and claws tear at the edges of the wound and irritate the skin, so the area swells and heals more slowly.
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The edges of the wound coming apart
If the edges start to separate the area becomes open, swells and may begin to bleed or ooze.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- Whether the swelling is growing, and how it looked the day before
- Whether the skin around the wound is warmer than the skin nearby
- Whether fluid is coming from the wound, and its colour and smell
- Whether your dog licks or scratches the wound, or guards it and will not let you touch it
- Whether it has a fever, eats less or seems dull
- Whether the edges of the wound stayed together or have started to part
When to book a routine visit
A swollen or hot wound should be shown to a vet the same or the next day rather than left to change on its own. Bring photos and say when you first noticed the swelling.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Delayed bleeding after a procedure Blood and immunity This is a condition in which bleeding after a tooth extraction or another veterinary procedure starts not straight away but hours or even days later. At first everything can look fine, so before any procedure it is worth telling the vet if this has happened to your dog before. Bleeding that starts later can be dangerous, and then the dog needs a vet immediately.
- Skin cuts and tears Skin and coat This is an umbrella term for a range of skin wounds, from shallow scrapes to deep cuts or tears left by sharp objects, branches, fences or bites from other animals. Thin or loose skin, the paw pads and the edges of the ears are injured more easily. Even a small wound can be deeper than it looks and can become infected, so how badly the tissue is damaged is for a vet to assess.
Body systems: Blood and immunity Skin and coat