Why is my dog suddenly aggressive when I touch his leg or belly?

I agree. If Frankie has never exhibited this behavior before, it could be a sign of skin sensitivity which could be due to several things including allergies, skin mites, flea bites, or other possible causes. You can try adding in an omega 3 fatty acid supplement for dogs, this can help improve the skin health. You may also try changing his diet to something like Royal Canin or Nutro as they are aimed at skin health. Check the skin daily for signs of infection or irritation such as redness or scabs. If these are seen, have him examined by the veterinarian who may prescribe medications. Best of luck and please feel free to post any additional questions.

Since this sounds like a sudden change I would recommend making an appointment with your veterinarian to rule out a medical problem first. It is possible that he is painful somewhere and is reacting this way due to pain. I would try not to pick him up until you can see a vet, or wrap him in a thick towel before picking him up. If he seems healthy, you can then discuss what could be causing this behavior with your vet or your vet could refer you to a local animal behaviorist.

Poor guy. The left lower side of the belly is where the bladder normally sits, but unsure exactly where you are touching on the body without seeing or feeling myself. The exact location is key because certain organs lie in certain positions. However with just this symptom of discomfort from touching I would have to assume that an internal organ (perhaps the bladder) is painful. He should however have other symptoms like excessive urination, excessive drinking or foul smelling urine to corroborate the pain elicited during palpating the belly. If this is the case then a urinalysis and exam would be the best course of action to evaluate the urine and treat any abnormalities seen with appropriate and selective medication. If the bladder does not seem to be the organ in mind, then a further evaluation by a vet to feel the belly is recommended, especially if your pet has any other symptoms of illness. However keep in mind, that if you notice any swelling of the belly or dissension and your pet is acting completely normal, then this should still be seen because organomegaly (enlarged organs), fluid in the belly or a growth (mass) is highly suspected and its best to look into this with a professional exam.

I would recommend to take Caesar in for an exam to make sure there's no evidence of pain. If no medical reasons are found, then I would suspect this is a behavioral problem. Caesar is now nearing adulthood so he may be trying to figure out where he fits in the pack. I would recommend to work with a professional dog trainer. Aggressive behavior always has the potential to become very bad and you don't want anyone getting hurt. I would start training immediately before the behavior becomes ingrained. Bad habits can be changed but its harder. I hope this helps.

Any abrupt change in demeanor or behavior should be checked by a vet as soon as possible. Sometimes this is the only way our pets can tell us something is wrong. Hiding and not wanting to be touched can indicate pain or discomfort. She could have a hidden injury you weren't aware of, she could have an infection of some kind, eaten something that didn't agree with her, there are a number of possibilities. Your vet will do an exam, labwork and probably x-rays and based on these results will be better able to tell you what is wrong and how best to treat it.

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.

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.