Signs of canine hypothyroidism — too little of certain thyroid hormones — often come on subtly and slowly, progressing over years, and therefore can be easy to miss or misattribute to advancing age. These signs often include poor coat quality, lethargy, mental dullness, exercise intolerance, and weight gain. If this constellation of symptoms describes your dog, it’s worth discussing whether an evaluation for hypothyroidism is in order, as treatment is available.
Note that active working dogs and certain breeds may have thyroid hormone levels that naturally fall below the reference values and do not necessarily indicate disease. These breeds include sighthounds such as greyhounds and salukis. Certain medications can also suppress thyroid hormone levels. That needs to be considered as well in considering a diagnosis.
