What this means
A simple scratch or graze usually closes within a few days. If the spot stays open for weeks, forms a scab that falls off again, bleeds or weeps, and the edges thicken or turn uneven, something is getting in the way of healing. It may be a wound that truly started as one, or a skin lump that first looked like a small pimple or mole and then began to ulcerate.
There are many possible reasons: constant licking or scratching, infection, a foreign body left in the wound, a pressure sore on a spot that is easily rubbed, a skin disease or a growth. Only a vet can examine the spot and decide whether a sample should be taken from it to learn what it is hiding. It cannot be told from a photo or a glance, so do not wait for the sore to heal on its own.
Before the visit, write down when you first noticed the sore, how it looked then and how it has changed. Photograph it next to a coin or a ruler so the size can be seen. Notice whether your dog licks it, whether it bleeds, whether other similar spots have appeared nearby and whether your dog has become dull or thin.
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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Constant licking or scratching
When a dog keeps licking or scratching at a spot, the edges of the sore never get the chance to close. Itch or pain in that place is often the reason.
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Infection in the skin
Germs in an open spot can hold healing back for a long time and cause pus or an unpleasant smell.
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A foreign body under the skin
A thorn, grass seed or splinter can stay under the skin and keep a small wound or channel reopening.
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A pressure sore
On elbows, heels or other hard-lying spots the skin can wear through and heal badly, especially in older dogs.
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A skin lump or growth
Some growing skin lumps begin to ulcerate, bleed and fail to heal. Whether a lump is dangerous is something a vet finds out by examining a sample.
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A skin disease
Some skin diseases leave sores that keep coming back. Other skin changes are often seen alongside.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- When you first noticed the sore and how it looked then
- Whether it is growing, changing colour or has thickened edges
- Whether it bleeds or weeps, and what kind of fluid
- Whether your dog licks, scratches or guards it
- Whether other similar spots or small lumps have appeared nearby
- Whether your dog is duller, eating less or losing weight
When to book a routine visit
A sore that has not healed in a couple of weeks, keeps reopening or is growing should be shown to a vet rather than left to see whether it closes by itself. Bring photos and say how it has changed.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
Body systems: Cancer