Dog Hair Loss and Thyroxine

Hypothyroidism is the most common canine endocrine disease, per the University of Georgia College of Veterinary Medicine. Hypothyroidism occurs when not enough hormones are produced. One of the most common symptoms of hypothyroidism is alopecia, or hair loss. If your dog is diagnosed with hypothyroidism, medications can be prescribed to treat this disease. The medication that is the first line of treatment for hypothyroidism is thyroxine.

  1. Features

    • The thyroid is a gland that is located in the neck of a dog and is responsible for producing hormones. Hormones help regulate the metabolism. Hypothyroidism is the inability of the thyroid to produce hormones, specifically T3 and T4 hormones. In 95 percent of the cases of canine hypothyroidism, this impaired ability is due to the destruction of the thyroid gland by the dog's own immune system, per Doctors Foster and Smith Pet Education. Hypothyroidism is also caused by certain types of cancer and several medications may cause hypothyroidism.

    Factors

    • Hypothyroidism is most common in middle-aged dogs. It usually occurs between four and 10 years of age, but can occur at any time. Certain breeds may be predisposed to this disease including golden retrievers, greyhounds, and Doberman pinchers.

    Symptoms

    • One of the most common symptoms of hypothyroidism in dogs is hair loss. Hair loss occurs in approximately 65 percent of dogs diagnosed with this disease. The hair loss is most visible on the trunk and the tail. Other symptoms of hypothyroidism are lethargy, weight gain, skin problems and a dry coat.

    Treatment

    • Diagnosis of hypothyroidism is made by simple blood tests that look at the hormone levels. Treatment for hypothyroidism is a daily dose of a synthetic thyroid hormone called thyroxine. Thyroxine results in the normalization of the T3 and T4 hormones, according to the University of George College of Veterinary Medicine. Thyroxine, also called Levothyroxine or L-thyroxine, is in tablet form and is given orally. The dose and frequency of this drug will depend on the severity of the disease and the individual dog's reaction to this medication. Blood tests are taken every two to four weeks and the medication is adjusted accordingly. The goal of treatment is to maintain sufficient hormone levels throughout the day. Thyroxine must be taken for the remainder of the dog's life. Thyroxine has no known side effects, but may interact with other medications such as epinephrine, norepinephrine, warfarin, insulin or estrogens, per the Doctors Foster and Smith website.

    Considerations

    • Once a therapeutic dose is determined and administered for a period of time, symptoms will begin to resolve. It may take 4 to 6 weeks to see a change in the symptoms. Discontinuing thyroxine will cause a return of the symptoms.