Medical Causes of Aggression in Dogs

Canine aggression can be a very dangerous problem. According to a survey by the Centers for Disease Control and Prevention in Atlanta, nearly two percent of the U.S. population (more than 4.7 million) fall victim to a dog bite annually. According to the website Dog Bite Law, one in six bites are serious enough for medical attention. Although some of these bites are purely accidental, some are brought on by aggressive canine behavior.

  1. Behavioral Seizures

    • According to Pet Place, aggression can occur when dogs suffer from partial seizures in the hypothalamus or limbic system, the part of the brain that controls aggression. Breeds like the cocker spaniel, golden retriever and poodle are known for this sudden, unprovoked aggression. According to Pet Place, the signs of seizure-related aggression include: a sudden mood change prior to the seizure, sudden unprovoked violent aggression, salivation, dilated pupils and evacuation of anal sacs. A seizure-related attack can last several minutes, hours or days, according to Pet Place.

    Hypothyroidism

    • According to website k9aggression, aggression can be caused by hypothyroidism, a common disease involving the endocrine system, which secretes hormones into the body. Hypothyroidism is when levels of thyroid hormones become unusually low. K9aggression states that more than 50 dog breeds and crosses are affected by hypothyroidism. According to Pet Place, the signs and symptoms of hypothyroidism include an increase in body weight, lethargy and hair loss. Blood work is done to check the levels of thyroid hormone to make a diagnosis.

    Brain Tumors and Head Trauma

    • A brain tumor, according to k9aggression, can cause shifts in mood and temperament. Sometimes these changes in temperament include aggression but could also include excitability, weakness, decrease in appetite and seizures. A head trauma affects the brain in a similar way to a brain tumor, in that a trauma or injury to the brain may interfere with the normal functioning of the brain and can cause changes in temperament such as aggressive behavior.