Hypothyroidism is a common condition in middle aged dogs. In this disease, the thyroid does not produce enough thyroid hormone. The vast majority of cases involve primary hypothyroidism, the cause of which is unknown.
Some breeds seem to be more susceptible than others: the disease is more commonly seen in Dobermans, Boxers, Golden Retrievers, Cockers, English Bulldogs, Irish Setters, Miniature Schnauzers, Poodles, Dachshunds, Great Danes and Airedale Terriers.
Thyroid hormone regulates the activity of metabolism. Dogs with a deficiency of this hormone will have a lower metabolism.
Symptoms
The first thing that is usually noticed is that the dog becomes very calm: it sleeps more and wants to play and walk less. Added to this is an increase in weight, although the animal does not eat more, and sometimes even less. Many dogs with hypothyroidism feel cold more easily and show muscle weakness.
The most noticeable symptom is the skin changes. Baldness is a common symptom and usually occurs symmetrically on both sides. Most commonly affected are the sides of the abdomen, tail, armpits, and underside of the neck. The hair will become duller and fall out faster. Over time, strong black pigmentation and thickening of the skin often occurs. These skin changes make the dog more susceptible to skin and ear infections.
Other symptoms include reproductive problems, muscle and nerve problems, and cardiovascular problems.
Diagnosis
The symptoms usually give an indication of the problem.
Usually, the diagnosis is made through a blood test.
In some cases, the diagnosis can be made through a biopsy of the skin.
If still inconclusive after these tests, but the dog is suspected to be hypothyroid, a test treatment can be tried.
Therapy
The treatment of hypothyroidism consists of administering thyroid hormone tablets (l-thyroxine or levothyroxine).
Prognosis
The prognosis is very good with primary hypothyroidism and proper treatment. The symptoms will go away with treatment, unless the skin changes have progressed too far.
The patients will have to be followed up regularly.
