Endocrine Alopecia in Cats

Overview of Feline Endocrine Alopecia

Feline endocrine alopecia is a rare skin condition of cats. The cause is unknown but it is hypothesized to be hormonal in origin. Several hormones have been considered to play a role in feline endocrine alopecia including thyroid hormone, estrogen and testosterone.

Below is an overview of Endocrine Alopecia in Cats followed by in-depth information about the diagnosis and treatment options for this problem.

Affected cats experience thinning of the hair or hair loss, which has a similar distribution on both sides of the body including the flanks, abdomen and hind legs. Cats may spend considerable time grooming themselves without being observed by their owners. In many instances, hair loss is self-inflicted rather than spontaneous. An important first step in affected cats is to determine whether or not the hair loss is self-inflicted.

One approach is to use a plastic cone collar (an Elizabethan collar) to prevent the cat from grooming and observe whether or not the hair grows back. If the hair grows back, the next step is to determine why the cat is grooming excessively. In most instances, excessive self-grooming is a sign of allergy rather than being psychological in origin.

If the hair does not grow back, self-grooming is not the cause and your veterinarian will proceed with a diagnostic evaluation to determine the cause of the hair loss.

Feline endocrine alopecia primarily is a cosmetic problem. An important initial step is to rule out medical conditions that may mimic this condition and would require medical therapy.

Conditions that may mimic feline endocrine alopecia and require medical therapy include allergies of various types, dermatophytosis (ringworm) and parasitic diseases.

Veterinary Care

If other diseases are ruled out, a diagnosis of feline endocrine alopecia is made. Fortunately, this condition is primarily a cosmetic condition and does not jeopardize the health of the animal.

Cats with feline endocrine alopecia are otherwise healthy. Treatments used in an attempt to stimulate regrowth of hair have the potential to cause adverse effects, some of which are potentially serious. Also, because the cause of feline endocrine alopecia is unknown, several treatments may be tried before a response is observed.

Home Care

In-depth Information on Feline Endocrine Alopecia

In the past, feline symmetrical alopecia also has been called feline endocrine alopecia because it was thought to be due to a hormonal imbalance. However, the actual pathogenesis of this disease remains unknown.

No breed predilection has been reported. This condition is seen most frequently in neutered cats. Neutering at an early age has been hypothesized to play a role in the development of feline endocrine alopecia. Definite conclusions, however, cannot be drawn because great variation exists among affected cats in the time from neutering to the occurrence of hair loss.

In one study, many affected cats were thought to respond to thyroid hormone replacement like liothyronine. As a result of this study, decreased thyroid gland reserve was proposed as a cause of this condition. As a group, affected cats had decreased response of their thyroid glands to thyroid-stimulating hormone (TSH), but some affected individuals had normal serum concentrations of the thyroid hormones, thyroxine (T4) and liothyronine (T3). Low thyroid gland reserve has been identified in humans after radioiodine therapy, surgical removal of the thyroid gland or cessation of prolonged thyroid hormone supplementation.

Feline endocrine alopecia has been hypothesized to result from a remnant of thyroid tissue that already has been maximally stimulated by the body’s own thyroid-stimulating hormone (TSH) and cannot further respond to thyroid-stimulating hormone (TSH) administered as part of a diagnostic evaluation. It is important to note, however, that response to liothyronine (T3) therapy in affected cats does not necessarily imply the presence of thyroid gland disease because normal cats may temporarily grow hair back after thyroid supplementation. Furthermore, evaluation of serum liothyronine (T3) concentrations appears to be an unreliable indicator of thyroid function due to the location and function of T3 inside of cells.

Currently, feline endocrine alopecia is thought to have multiple causes and affected cats may respond to several different forms of hormonal replacement.

Clinical Presentation

Diagnosis In-depth

It is important to determine whether the alopecia is self-inflicted or spontaneous. Cats may spend considerable time grooming themselves while unobserved by their owners, and frequently it is not obvious whether the hair loss has been self-inflicted or spontaneous.

Treatment In-depth


Some cases of feline symmetric alopecia are idiopathic (of unknown cause) whereas others are allergy-related. The only known underlying disease that can be prevented is flea allergy. Thus, aggressive flea control measures are strongly recommended.