Why is my Staffy puppy suddenly aggressive after hitting his head?

If Shadow had an injury from bumping his head a few weeks ago, I'd have expected to see symptoms before now. I'm concerned about this sudden aggression which can be a sign of pain or illness. Have him seen by a vet for this.

If this has only recently happened i would give him some time, he is likely still scared by it. If it has been a while he may have developed a ptsd like mental state or he may associate people with the accident. On the same hand who could have an underlying injury from it. I would have him checked mefically first, then if it seems behavioural i would have a behaviourist assess him to determine his mental state.

If the bite occurred on or around the puppy’s head then based on the symptoms you are describing I would be concerned about head trauma. If there is any sort of trauma to the head the brain can swell causing abnormal neurological behavior like you are describing. If you know the bite occurred in the head then I recommend taking the puppy to be checked out by a veterinarian. It also goes without saying that for now you need to keep the older dog away from the puppy at all times until they become more used to each other. Hopefully the bite just cause some local discomfort and your puppy will be back to himself in no time. I hope this helps. Thanks for using Petco Pet Education Center, formerly Petcoach. Best of luck.

It's not normal for a 4 month old to be scared or aggressive. I would recommend getting an appointment with a veterinary behaviorist (this person is a vet, not just a layperson) if at all possible -- your vet may have recommendations for someone nearby. It sounds like he could have been scared by the tackling incident, but it's still atypical for such a young dog to be aggressive. It would be like your 2 year old threatening to beat you up --- it's just not how their brains work at that age. The behaviorist can assess him and likely give you a pile of exercises to do at home and some medications. In the mean time, or if you can't take him to a behaviorist, avoid anything that makes him scared and hand feed him all his food as "treats" throughout the day as rewards for interacting with the family.

Hi and thanks for using Petco Pet Education Center, formerly Petcoach! Sorry to hear about Bruno. When a puppy shows aggression, I immediately advise neutering him to remove the male hormone-driven behaviors. I would advise taking him to your veterinarian for their opinion also. He may have some medical reason for his sudden onset of aggression. Your vet can gather a history, perform an exam and then offer a diagnostic/treatment plan based on their findings. Possible tests include fecal/blood/urine tests and x-rays to look for underlying medical problems that could cause aggression. If a behavioral problem is suspected, then neutering, behavior modification, and drug therapy can be tried. I wish you good luck with Bruno

Head trauma is always a cause for concern. Since this happened yesterday, there should have been some improvement with your pup if he suffered an injury such as a mild concussion. Sleeping a lot is not so much of a concern since young puppies normally sleep most of the day, but if you also see signs such as unresponsiveness, a head tilt, circling while walking, unequal pupil size, twitching of the eyes, ataxia (wobbly gait) or [vomiting](https://www.petcoach.co/dog/condition/vomiting-1/) then he should be [seen by a veterinarian immediately](https://www.petcoach.co/article/how-to-handle-a-pet-emergency/). If there is a bump, it may be a seroma (blood filled sac). This can treated by your veterinarian by either draining the area or trying a veterinary anti-inflammatory medication. Do not medicate him with anything OTC without the advice of your veterinarian as [many OTC drugs can be toxic](https://www.petcoach.co/article/7-human-medications-that-are-dangerous-for-your-pet) to dogs.

I'm sorry to hear that Mylo was attacked! It is concerning that he is not drinking, moving his head abnormally and bumping into objects. This could be occurring due to head trauma or neurologic deficits caused by the attack, and some of these signs can take a longer time to present if there is swelling in the brain. I do recommend taking Mylo back to the vet for another exam to reassess his neurologic function and cranial nerve responses. The vet may also need to give him fluids since he is not drinking and puppies are more susceptible to the effects of dehydration than adult dogs. I hope that he's on the mend soon!