Puppy Thyroid Symptoms

Veterinarians classify thyroid problems in puppies according to where the cause of the thyroid problems originate. Hypothyroidism occurs when the puppy does not produce enough thyroid hormones. Primary, secondary and tertiary hypothyroidism occurs as a result of hypo activity of the thyroid gland, pituitary gland or hypothalamus. Another rare form of hypothyroidism includes puppies born with a birth defect that affects the syntheses of thyroid hormones. Hyperthyroidism, a condition in which the thyroid gland produces too much thyroid hormone, occurs very rarely in dogs.

  1. Body Changes

    • The most common sign of hypothyroidism in puppies, weight gain, occurs rapidly. Puppies with hypothyroidism often exhibit symptoms of dwarfism, such as large tongues, short legs in proportion to body size and abnormal development or absence of permanent teeth. Increased lethargy and general weakness occur as the problem progresses. A puppy diagnosed with hyperthyroidism may exhibit a sudden loss of weight despite receiving adequate nutrition. The puppy also may suffer from vomiting and diarrhea.

    Skin Problems

    • Puppies that exhibit dull or brittle hair, excessive shedding and oily or thickened skin often test positive for hypothyroidism. The skin may emit an odor because of secondary yeast infection due to compromise of the puppy's immune system via open sores or cracked skin. Puppies with hypothyroidism often exhibit a poor tolerance of cold temperatures and slow wound healing. Animals with hyperthyroidism may develop a dull and shaggy coat.

    Facial Symptoms

    • The puppy with hypothyroid problems may exhibit a "pop-eyed" look: a protruding tongue and eyeballs. The puppy's eyes may appear irritated due to decreased production of tears and decreased blinking. These puppies often appear dull or retarded, with lack of facial expressions and poor interest in interacting with humans or other dogs.

    Behavioral Problems

    • Puppies with increased levels of thyroid hormone (hyperthyroidism) often tend to be more aggressive and nervous than puppies of the same breed or even other puppies of the same litter. Puppies with an underactive thyroid often show little interest in interacting with others. In older puppies and dogs, changes in thyroid function may cause the sweet dog to become aggressive and the more active dog to become fearful and shy.

    Cardiac Symptoms

    • Hypothyroidism in puppies causes the heart rate to slow, contributing to the animal's cold intolerance and lack of energy. The puppy may develop anemia due to poor circulation and oxygenation of the blood. High blood cholesterol also presents as a common problem associated with hypothyroidism in dogs. Hyperthyroidism, on the other hand, causes the heart rate to increase, with associated symptoms of palpitations and increased respiratory rate.

    Rare Symptoms

    • In rare cases, especially in cases involving severe thyroid disease, puppies may experience seizures, loss of smell or taste and cardiac problems. Puppies that do not receive timely treatment for thyroid problems may develop chronic hepatitis.