What this means
A weeping sore often appears where a dog keeps licking, chewing or scratching. The hair around it mats together, the skin is red and moist, sometimes pus or a crust is visible, and your dog may grumble or pull away when you touch it. The sore can spread very fast, sometimes within hours.
The place and circumstances give clues. It is often the head, neck, sides, hips or base of the tail, but it can be anywhere. Notice whether there was itching beforehand, bites, a damp coat after swimming or long lying on the same spot, and whether there is just one sore or many.
Do not use any human products or creams, and do not let your dog lick or chew the sore. That makes the inflammation worse, and the cause that emerges decides what happens next. Photograph the sore so the vet can see how it has changed.
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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Local skin inflammation after licking or scratching
A spot that is licked or chewed for long becomes wet, red and painful. The hair mats and the inflammation spreads quickly.
About the condition: Hot spots (acute moist dermatitis) -
Skin infection
Bacteria multiply on damaged skin. The skin is red, with pus, crusts and an unpleasant smell.
About the condition: Skin infections -
Allergy and itching
Environmental, food or flea allergy causes itching that makes a dog scratch or chew the skin until a sore appears.
About the condition: Allergies (food, skin and environmental) -
Parasites
Fleas or other external parasites can cause strong itching. The sore often appears where your dog scratched most.
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A skin wound or graze
A scratch, cut or bite can start to weep and become infected, especially if your dog licks it.
About the condition: Skin cuts and tears -
A damp coat and skin that has not dried
After swimming or a bath, a damp coat can develop local inflammation, especially in dogs with thick coats.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- Where the sore is and how big it is
- How fast it is growing
- Whether there is pus, a crust or a bad smell
- Whether your dog licks, chews or scratches it
- Whether there was itching, fleas, swimming or a bite beforehand
- Whether there are more sores elsewhere
- Whether your dog eats, drinks and acts as usual
When to book a routine visit
Show a vet any weeping or pus-filled sore the same day or the next. Do not use any products yourself, and do not let your dog lick or chew at it.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Hot spots (acute moist dermatitis) Skin and coat A hot spot, or acute moist dermatitis, is a patch of skin that suddenly turns moist, red and painful, which the dog makes worse by licking or scratching it. It can spread within hours, and it can be set off by something else, such as itching from parasites or an allergy. A vet should look at the patch and decide what to do.
- Skin infections Skin and coat Skin infections are caused by bacteria or yeast that start to multiply when the skin's defences are weakened, for example by an allergy, parasites, moisture trapped in skin folds or constant scratching. An infection can stay on the surface or reach the deeper layers of the skin, causing pain and intense itching. What caused the infection and what keeps it going is for a vet to work out.
- 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.
- 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: Skin and coat