Adrenal Disease in Ferrets

What Is Adrenal Disease in Ferrets?

All mammals have what is known as the endocrine system. This is a collection of organs and glands in the body responsible for producing hormones and maintaining their levels in the body. Two adrenal glands are part of this system.

Adrenal glands are small, located near the kidneys, and are responsible for regulating stress hormones, such as cortisol, steroids, and sex hormones. If something goes wrong with the adrenal glands, the typical mammal either over- or under-produces steroids and stress hormones.

Ferrets are special in that they can develop adrenal disease, which is characterized by the overproduction of sex hormones, due to a tumor in their adrenal gland(s). This condition is incredibly rare in just about any other animal, but it occurs in up to 25% of ferrets in the U.S.

Ferrets may die in as little as a few months if adrenal disease is left untreated. If you notice any of the following symptoms in your ferret, contact your veterinarian right away.

Symptoms of Adrenal Disease in Ferrets

Signs of adrenal disease can be slow to develop in ferrets. It may appear as only seasonal hair thinning at the tail or some mild behavioral changes. Over time, symptoms of adrenal disease in ferrets persist and may include:

• Equal hair loss on both sides of the body starting at the tail that can spread through the back and trunk

• Swollen vulva or mammaries in females

• Vaginal discharge

• Increased drinking with increased urination

• Swollen belly

• Aggression toward people or cage mates

• Difficulty defecating

Increased sex hormones can cause an enlarged prostate in male ferrets. Symptoms of this include:

• Struggling to urinate or failure to pass urine

• Vocalizing while urinating or defecating

Causes of Adrenal Disease in Ferrets

Adrenal disease in ferrets has been studied at length because their adrenal tumors are different from just about all other species. Comparison between populations of ferrets in several countries have helped identify some of the most likely causes of adrenal disease in ferrets.

• Neutering age—Ferrets in the U.S. are neutered at 4–6 weeks of age, and other countries that also neuter at this age have similar rates of adrenal disease. Countries that neuter their ferrets closer to 1 year of age have nearly no cases of adrenal disease.

• Genetics—The pet ferret populations in the U.S. come from one breeder and have become genetically isolated. Their genes may be causing the tumors, but it appears more likely that their genetics predispose them to being more sensitive to the hormone changes after neutering, which trigger tumor growth over time.

• Photoperiod—Ferret breeding season is dictated by the length of daylight. Artificial lighting in the home may be causing a ferret’s adrenal glands to think they need to produce sex hormones in support of breeding year-round, instead of seasonally. This stress can be contributing to tumor growth in their adrenals.

How Veterinarians Diagnose Adrenal Disease in Ferrets

The most common symptom of adrenal disease in ferrets is symmetrical hair loss at the tail. This symptom can be enough to diagnose the disease.

Blood work assessing hormone levels is the best way for vets to achieve a definitive diagnosis. Imaging from an ultrasound may detect an enlarged adrenal gland or prostate. Other imaging, biopsy samples, and tests can sometimes be used for diagnosis, but are less accurate.

Treatment of Adrenal Disease in Ferrets

If a ferret only has adrenal disease in one adrenal gland, surgical removal of the affected gland can cure the disease. However, the other adrenal gland can become diseased at any time. Both adrenals cannot be removed entirely; Adrenal glands help regulate normal body functions, so removing both glands completely can cause other terminal problems for the ferret.

Medicinal treatment is now more common for adrenal disease in ferrets due to lower cost and risk than surgical options, regardless of whether one or both adrenals are affected. 

Treating adrenal disease medicinally is a multi-step process, including the administration of:

• Deslorelin—a chemical that mimics a hormone found naturally in ferrets. Deslorelin slowly decreases adrenal gland stimulation and hormone release. This can significantly improve symptoms but doesn’t treat adrenal tumors themselves. Deslorelin comes as an implant that can be injected under the skin, leading to resolution of symptoms within two to six weeks that lasts three to 30 months.

• Leuprolide—a chemical that mimics the same hormone as deslorelin. Leuprolide is an alternative that requires monthly injections, in contrast to deslorelin’s one-time injection.

• Melatonin supplementation may help offset the negative effects of artificial lighting, especially during summer when days are longer. A long-lasting implant can be injected under the skin every six months to make treatment simple.

• For ferrets with enlarged prostates affecting their quality of life, medications such as flutamine, bicalutamide, or finasteride can be used to shrink the prostate and alleviate symptoms.

• Anastrozole can be used to alleviate excess estrogen levels caused by adrenal disease in ferrets.

While not common, some ferrets with adrenal disease show signs of severe anemia (not enough healthy red blood cells) and may require a blood transfusion.

Recovery and Management of Adrenal Disease in Ferrets

Daily medication may be given to ferrets that are not treated with the use of implants. In addition, pet parents can set a ferret’s lighting on timers to mimic daylight which may help control symptoms.

Ferrets that have had adrenal gland surgery or are under medicinal management should anticipate six-month re-checks by your veterinarian for assessment and potential blood work.

Progression of adrenal tumors and/or prostate enlargement will continue over time. In male ferrets that weren’t already showing signs of prostate enlargement, it can develop any time. An enlarged prostate may cause urinary obstruction which can be very painful for ferrets.

Adrenal disease in ferrets can also lead to insulinomas (tumors in the pancreas).

A ferret with poor adrenal function may show signs of lethargy and inappetence, which can be treated with steroid supplementation.

Prevention of Adrenal Gland Disease in Ferrets

Though not legal everywhere, delaying neutering can prevent adrenal gland disease in male ferrets.

Ferrets must be sold neutered in the U.S. and are therefore neutered at a young age. Leuprolide injections or deslorelin implants may prevent adrenal gland tumors in these ferrets. Your veterinarian can help you determine what makes sense for your ferret based on their health and history.