Dog Aggression & Hypothyroidism

The information listed below is not intended to replace the advice, counsel, or assistance of licensed personnel. It is always recommended that you seek the help of your veterinarian.

When a dog starts showing aggressive or reactive behaviors it is important to rule out any medical causes of this behavior. One of the most overlooked medical conditions is hypothyroidism. Different dogs may exhibit different clinical symptoms such as unexplained weight gain, hair loss, or skin/ear infections. Typical behaviors are incessant whining, nervousness, anxiety, fears & phobias, disorientation, hyperventilating, lethargy, depression, and irritability. Some dogs show siezure-like disorders. After an episode, most dogs will behave as though they were coming out of a trance like state, unaware of their previous behavior. The ONLY way to really know if your dog has hypothyroidism is to run a full Thyroid Antibody Panel (Thyroid 5™). A simple T4 test will not be sufficient as it is rarely useful when behavior problems are involved.

Labs vary in quality and experience, and it is recommended you contact Dr. Jean Dodds, the foremost authority on Canine Hypothyroidism, located at Hemopet.org. You will want to ask your Vet for assistance with working with Dr. Dodds. Ask your Vet for a copy of the results so you can also analyze the results as most Vets will read the test, and as long as the dog's results fall anywhere in between the laboratory's "Normal Range" they will tell you (and believe) that the dog is not hypothyroid. Borderline hypothyroidism is a condition where the dog is definitely suffering from a weakened thyroid system, but it is not yet severe enough to register out of the "Normal Range". Just because it has not reached an extreme state yet, does not mean that it is not affecting your dog's health and behavior negatively. Be sure to discuss results with Dr. Dodds.