Friendly dog suddenly aggressive. Is it from an old head injury?

It would be unusual for this to occur secondary to a bump on the head, but it is possible to see personality changs with major head trauma. I would recommend having your vet examine him again to look for signs of neurologic problems. Your vet can also refer you to a behaviorist who could help determine whether or not this is simply behavioral and unrelated to the accident.

You need to take him to a vet for an exam. Any abnormal behavior, especially towards the side of aggression, need to be taken seriously. It very well could be a brain tumor. I don't know. It could also be the beginning stages of seizure activity. It could be from pain somewhere in/on his body. He needs a vet exam to try to find out what is going on with him.

Hi there. It's unusual to see aggression issues suddenly start in a dog this age without any history of aggression, so I would be suspicious that Danny may have a medical problem causing this. He may be painful or uncomfortable for some reason, or may have a hormonal problem such as hypothyroidism or Cushing's disease causing him to be more irritable. I would recommend taking him to the vet for an exam and possibly lab work to see if an underlying cause can be found.

Oh dear! That is a worry for sure! It's really important that you don't get hurt, because dog bites can be pretty serious. I would suggest making an appointment with your vet to talk about possibilities. They might be able to link you up with a behaviorist, or dog trainer that could help a lot. There also could be medications that might help. Or, like you said, there could be a medical problem that is upsetting him.

Hi there. Yes, this definitely sounds concerning. Sudden behavior changes are often due to an underlying medication problem - Wanda may be in pain or not feeling well, or may have ingested something toxic that is causing neurologic symptoms. I would recommend taking her to the vet for an exam right away. He/she can do blood work or other testing if needed to help diagnose the problem and get her started on appropriate treatment.

Any dog that all of a sudden acts aggressive it is usually due to some type of pain in the body. If he is not eating he may have an intestinal obstruction and that is painful. I suggest you get him to a vet for an exam.

I'm sorry to hear that you're having this problem! If this has been a fairly sudden behavior change for Elsa, the first thing I would suggest would be to have her examined by a vet to see if there may be a medial reason for the aggression - many illnesses including thyroid problems and neurologic issues can cause sudden mood swings and behavior changes like this, as well as anything that may be painful such as an injury of some kind, arthritis, etc. If your vet determines that Elsa is healthy, then I would strongly recommend making an appointment with a veterinary behaviorist as the next step. Aggression towards humans is a serious and complex behavior issue that needs to be handled by a professional who can work with your dog in person. The behaviorist will evaluate your dog and help you determine what is triggering the aggression, then put together a detailed training plan to work on the problem. You can search for a board-certified veterinary behaviorist in your area here: www.dacvb.org