Signs of Hypothyroidism in Dogs

The thyroid gland is a small gland in a dog's neck. This gland is an endocrine gland that secretes hormones for body development. Hormones from the thyroid gland control body metabolism, the use of calcium and the way cells use oxygen. When the thyroid does not give off enough hormones, the dog develops hypothyroidism. A hypothyroid dog often has serious health problems.

  1. Significance

    • Hypothyroidism is the most common endocrine problem in dogs. It primarily affects adult dogs. Hypothyroidism is more common in hunting breeds such as Golden Retrievers, Labradors, Shelties, Doberman Pinschers and Greyhounds. The disease is not common in toy or miniature dog breeds. Hypothyroidism may have different causes such as thyroid gland atrophy or other disorders but the diagnosis and treatment are the same.

    Weight

    • When a dog does not have enough thyroid hormone, it may gain weight even when eating less food. The metabolism is affected so that the body turns food into fat instead of muscle or energy. The dog has excess fat from its neck through the body trunk to the hips. The dog may weigh two or three times its normal body weight even though it is eating the same amount of food.

    Appearance

    • The dog often has dry, flaking skin and skin sores. The coat becomes thin and brittle. The hair gets thinner over the back and hips. It may be soft like puppy hair without the normal oil of adult dog hair. The dog tail may lose its hair so that the tip is bare and mottled like a rat tail. Ear infections are common.

    Energy

    • The dog is often lethargic. It may sleep for long periods of time. When the hypothyroid dog exercises, often it is for short periods as the dog is easily tired. On walks, the dog may frequently stop and lie down on the walkway or grass until it has enough energy to get up and walk again.

    Treatment

    • Hypothyroidism is diagnosed through a blood test. The veterinarian tests for thyroid hormone levels in the blood. When hypothyroidism is confirmed, treatment is simple. The veterinarian prescribes thyroxin, a hormone replacement available under several brand names, in a tablet. The pill is usually given twice daily to maintain normal body function. Regular tests determine the correct thyroxin maintenance dosage.

    Recovery

    • The dog usually has quick positive improvement with thyroxin. The appetite and dog energy improves in about three days. Skin and coat improvement takes 3 to 4 months for many dogs. Weight loss begins within days and muscle tone improves with normal exercise. The dog must remain on the thyroxin the rest of its life.