Medical Causes of Aggressive Behaviors in Dogs

It is an unfortunate fact that often dog owners feel compelled to give up on their canine friend as soon as he displays aggressive behaviors by either giving him away, or worse, surrendering him to a shelter or permanently solving the problem by putting him down. Yet, there are cases where aggressive behaviors in dogs can be traced down to unforeseen medical conditions. What owners therefore may perceive as out of the blue, unprovoked aggressive attacks, can be instead attributed to something as justifiable as it can be from a dog's perspective: pain.

Veterinarians know this very well. In every veterinarian office tucked away in a handy drawer lies a set of different sized muzzles ready to be used. They know as a fact that even the most docile dogs may easily turn into vicious and snarling monsters at the sight of a needle or upon being treated for a painful wound. Yet, while in these cases, the pain is visible to the eye and quite obvious, there are sometimes medical conditions in aggressive dogs causing very subtle symptoms that can be hardly recognized and detected by even the most attentive owners. 

Owners of normally well mannered and well tempered dogs should suspect a medical condition when their dog acts aggressively out of the blue or in a gradual, yet, steady manner. Medical conditions should be suspected as well in stray dogs or rescue dogs with an unknown medical history. However, not all owners are willing to give these dogs the benefit of doubt, either out of ignorance (not knowing that there are actually conditions causing aggressive behaviors) or out of fear (the dog is a scary, must get rid of him as soon as possible!).

Truth is, an aggressive dog is a scary dog, especially when the aggression is targeted towards children and people. Such dogs are perceived as a liability, an animal too dangerous to be handled and is easily converted from man's best to man's worst enemy. A once much loved dog has progressively transitioned into a snarling vicious creature ready to bite. While many cases of dog aggression are behavioral in nature, it would be unjust to simply assume so without first attempting to rule out something medically going on.

This is why it is imperative to have a dog seen by a veterinarian right before calling a behaviorist or sending the dog to a trainer. Indeed, reputable dog behaviorists should ask for proof of a medical exam before seeing the dog. A dog behaviorist will never be able to fix a dog acting aggressively because of an underlying medical problem! Following are some medical conditions known to cause aggressivebehaviors in dogs.

• Hypothyroidism

This condition affecting the endocrine system of dogs is caused by a low count of thyroid hormones. This condition can be easily detected through a simple blood test. Affected dogs typically develop increased weight gain, hair loss, lethargy, low tolerance of cold, and behavior changes such as anxiety, fear and aggression. It is quite unusual for dog to develop aggression as a stand alone symptom when having this condition, however running a thyroid test is still worthy.The condition is easily treated with the long term administration of thyroid pills which will dramatically improve the dog's condition.

• Seizures

Dogs may develop aggressive behaviors in the post-ictal phase, following a seizure. Partial seizures in dogs that affect a particular portion of the brain responsible for regulating aggression may be also a contributing factor for aggression and aberrant behaviors. These types of seizures are often found in certain dog breeds such as a Cocker Spaniels, Springer Spaniels and Chesapeake Bay Retrievers.

• Brain Conditions

Trauma affecting certain regions of the brain may cause neurological symptoms including aggressive behaviors. These may take place after the dog has sustained brain damage. Brain cancer found often in senior dogs may be another cause for such behavior changes. Encephalitis, the inflammation of the brain may cause significant aggression in affected dogs. Rabies and Distemper are bacterial forms of encephalitis. Hydrocephalus, a congenital condition where the brain's ventricles become enlarged may cause a variety of neurological symptoms, sometimes including aggression

There are many more examples of medical conditions causing aggression in dogs. A dog reacting aggressively upon being pet on the head may be suffering from an undiagnosed ear infection, a dog suffering from arthritis may react defensively when laying down and feeling like he cannot remove himself from an irritating situation such as when being pestered by a child. A hearing impaired dog may easily startle and bite out of fear when approached without notice. A dog may turn grumpy when dealing with tooth pain. These are just examples of dogs that are dealing with pain and medical conditions that often cannot be detected by the most well meaning owners.

The first step therefore for owners of aggressive dogs is to keep the dog muzzled and sent up the vet's examination table before calling a dog behaviorist or heading to the closest dog training facility. Owners really owe this to man's best friends especially during these times when dogs need help the most.