Get Your Dog Care Questions Answered by Experts
Hi, this is Dr. Gabby. Bruising that occurs without know injury can be a sign of a problem with the platelets in the blood or the blood's ability to clot. There are a number of possible causes including infection, auto-immune disease, toxins like rat poison, or sometimes we do not know why it happens.
But it is important to get him to a vet as soon as possible and have blood work run.
Ideally he would see the emergency vet today. They are open 24/7.
The reason being if he cut himself he may bleed out if he can not clot his blood.
It is not something you can diagnose or treat at home.
If you can not get him to an emergency vet try to keep him as still as possible to avoid further bruising and injury.
Does that help? Do you have any additional questions?