Feline Endocrine Alopecia

Clare Deming
Feline alopecia

Alopecia is the medical term for hair loss. Historically, feline endocrine alopecia is a disease that has been recognized to cause hair loss in cats. However, as knowledge of feline medicine has expanded in recent years, this condition is no longer considered a single disease. While feline alopecia can be caused by an endocrine issue in rare circumstances, this is not the norm.

Understanding Feline Alopecia

Feline alopecia was thought to be a disorder of the endocrine system, which includes the pituitary gland, adrenal glands, thyroid and parathyroid glands, ovaries, and testicles. However, there is no concrete documentation that there is an underlying endocrine cause for this syndrome in cats. Only a few, isolated cases of feline alopecia can be tied to endocrine disease.

Symptoms

Common symptoms include:

  • Symmetrical hair loss
  • Lack of a rash or crusting
  • No apparent trauma or over-grooming

The hair loss often occurs on the underside of the cat and along the inner thighs.

Causes

Muller and Kirk's Small Animal Dermatology indicates that most cats exhibiting the symptoms of feline endocrine alopecia have underlying allergic or psychogenic disorders. A true endocrine cause of alopecia is exceedingly rare in cats. In most cases that appear to fit feline endocrine alopecia, a different cause can eventually be discovered. For example:

  • Cats will often over-groom themselves in response to pain, itching, or psychological factors, and this activity will cause them to lick their hair out to the point of visible thinning.
  • The Cornell Feline Health Center notes anecdotally that some cats with documented abdominal disorders (pancreatic disease, bladder disorders, or chronic intestinal disease) over-groom their bodies over the site of internal discomfort. This can also leading to hair loss.

Diagnosis

Diagnosing the underlying cause of hair loss in a cat can be a long process. The first tests your vet is likely to start with include:

  • A skin scraping to check for mange
  • A Wood's light exam or fungal culture to check for ringworm
  • Visual exam for fleas or other external parasites
  • A trichogram (where a vet checks some of the cat's fur under a microscope) to help determine if the cat maybe is over-grooming

Once your vet has ruled out more common causes and over-grooming, he may then evaluate your cat to see if there is an underlying endocrine issue that is causing the hair loss.

According to Small Animal Internal Medicine, your vet may want to perform blood tests to check thyroid function. Your cat's overall health and lab work results could raise the suspicion of an adrenal gland disorder such as Cushing's disease. You may need to consult with a specialist in internal medicine at this point, as these conditions are rare in cats.

Treatment for Environmental and Psychogenic Causes

Treatment for feline alopecia needs to be tailored to the underlying cause:

  • Environmental allergies can be managed through avoidance strategies or with medications.
  • Psychogenic causes may require consultation with a veterinary behavior specialist if the alopecia is long-standing or severe. Treatment can include environmental modification, pheromones, or medications.

Treatment for Endocrine Causes

If your vet determines that your cat's alopecia is caused by an endocrine issue, your cat may need hormonal supplementation. Historically, sex hormone replacement was recommended. According to Canine and Feline Endocrinology and Reproduction, megestrol acetate is the most common drug prescribed, however, the drug carries a significant risk of side effects. These can include:

  • Development of diabetes
  • Weight gain
  • Increased thirst and urination
  • Abnormal growth of the mammary glands
  • Mammary cancer
  • Liver toxicity
  • Pyometra (serious uterine infection).

If hair loss is the sole symptom of a cat's endocrine disorder, the risks of treatment must be weighed with the potential benefits. For some pets, no treatment at all may be preferable to the chance of these serious side effects.

Feline Alopecia Is Treatable

For the majority of cats, prompt evaluation, appropriate diagnostic steps, and specific treatments will help your cat find relief and quickly regrow a thick and healthy coat of fur. However, it is important to get your cat to a vet as soon as you notice symptoms.

Feline Endocrine Alopecia