Signs & Symptoms of Hypothyroidism in Dogs

Hypothyroidism is a disease in which the thyroid gland does not produce an adequate amount of thyroid hormone. This is a serious disease in dogs that can be diagnosed with simple blood tests. Because there are a multitude of symptoms that could indicate hypothyroidism, pet owners should work with their veterinarian to diagnose and treat their dog.

  1. The Facts

    • Hypothyroidism is a common canine ailment. It affects older dogs, with disease onset beginning around four or five years of age, although the symptoms may not be immediately apparent. Mid-size and large-breed dogs are more susceptible to hypothyroidism, such as the golden retriever, Doberman Pinscher and cocker spaniel. The disease is rarely seen in toy or miniature dog breeds.

    Causes

    • The thyroid gland, located in the neck, is responsible for regulating metabolism. Hypothyroidism means the dog's thyroid gland is not producing enough thyroid hormone, which affects many of the systems in the canine body. Hypothyroidism can be caused by an attack by the dog's immune system, as a response to thyroid cancer or as a side effect of some medications. Genetics also is a factor.

    Symptoms

    • Symptoms of hypothyroidism are common to many ailments, so one or two alone cannot be taken as a positive indicator of the disease. However, common symptoms include: weight gain, localized hair loss or a high rate of shedding, skin problems and a reduction in normal activity levels. Hypothyroidism can slow the animal's heart rate, increasing its sensitivity to cold weather.

      Anemia and muscle weakness also are signs of hypothyroidism. Symptoms that may not be as common include higher levels of cholesterol, ear infections, and sores on dog's body.

    Diagnoses

    • A veterinarian will help dog owners diagnose hypothyroidism. Many of the symptoms of hypothyroidism mimic those of other diseases, so the veterinarian will likely recommend blood work. There are several types of blood tests your vet can order to measure levels of thyroid hormones T3 and T4.

    Treatment

    • Hypothyroidism is treated with a synthetic hormone medication, available in tablet form so that dogs and their owners can avoid daily injections. The dose will vary depending on weight of the animal and veterinary recommendations. Many veterinarians will order follow-up blood work to measure thyroid hormone levels after treatment has begun, adjusting medication as needed. Lifelong treatment is necessary, but most dogs will live a long and healthy life with regular attention to the disease.