Hello,

My name is XX. XX and I would be happy to help you with your question about your dog. Can you please tell me a little more about your dog? What kind of dog is he? How old is he? How long has he been having this problem?

So he's a young, muscular, otherwise quite active and healthy dog. Which leg is affected, please?

And can you give me a more detailed description of exactly where the lump is and how big it is? Also, does it hurt him for you to touch it?

There are a few different possibilities that could create this kind of a painful lump on the hind limb of a young, pit mix. Let me go through them for you.

This could be some kind of wound abscess. It could be from an insect bite, a cat bite, or any other small puncture wound that would NOT leave a visible hole in the skin. The lump will get red and hot and may even rupture and drain pus or bloody fluid. Antibiotics will usually clear up an abscess, but the serious ones have to be lanced and drained. That's one possibility.

A painful lump like this could also be related to a swollen lymph node. That can happen in response to an infection, which may be bacterial or fungal, or even something as severe and scary as cancer. That's really rare for such a young dog, though. It takes a biopsy to diagnose that kind of problem.

It's also possible that this is a severe reaction to some sort of poisonous spider or insect bite or sting. If that's the case, cold compresses, antihistamines, and sometimes steroids can speed along the healing process.

Rarely, VERY rarely, this could be a tumor. This is not at all likely in such a young dog, but it is possible.

It is not a pulled muscle, sprain or strain, however. That wouldn't create a painful lump like this.

The best advice I can give you is to have it checked out by a veterinarian. It is concerning that it is causing this much pain in a dog I would NOT expect to be a crybaby at all. It must really hurt. The sooner your vet can tell you what kind of painful lump it is, the sooner he can get relief.

Sorry. It appears we have a slow and difficult connection. You are trying to tell me more about which muscle the lump is in?

I understand. That means it is NOT related to a lymph node, so you can cross that idea off the list. The other possibilities are still true, however.

We do not typically see the kind of muscle cramps that make a knot like you and I will get in our necks and backs in the legs of dogs. It is possible, however for them to get a painful knot in a muscle as a direct result of an injury. He would have to have been hit hard with a firm object in exactly that location to cause such a knot. I would expect the surrounding skin to be bruised as well.

Here's an idea? Did he recently receive any vaccinations? An injection into the muscle of the back leg could create a painful knot like this.

Okay. Then we can cross that off the list too. That leaves the possibilities of an injury or abscess (more common in a young dog), or a tumor (very rare in a young dog).

The only way to know for certain is to examine the area closely, perhaps even collecting some cells or fluid from it with a needle. For tough cases a biopsy is necessary. We usually don't get to that point, however, until we try treating something like this with anti-inflammatory medication and antibiotics first, just to see if that works.

I apologize for the slow connection we appear to have. I want to be sure I can continue discussing this with you until you're satisfied with the information I've given. I've done my best to be accurate, thorough and honest. The fact remains that over an internet connection the best I can do is discuss possibilities. I cannot diagnose. Posts on this website are made for general information only and in order to secure a diagnosis and treatment for your pet you must seek veterinary care.

I do hope you find this information helpful, and because some of the problems that can cause this type of swelling are serious, please take your dog to the vet for a thorough examination.

Also, please remember you can always post more to this thread and I will be alerted, even after you've clicked ACCEPT. I'm happy to help. Thank you for using Just Answer.