Elevated Sex Hormones in Dogs

Androgens are produced by the testes, ovaries and adrenal glands. Although they are primarily a male hormone, they are found in females also where they are a precursor to estrogen. In dogs, excessive androgen production is associated with hair loss and oily greasy skin (seborrhea oleosa) that is usually focused around the tail and rump area. This occurs primarily in male dogs that have not been castrated where it is called hyperandrogenism. It is more common in middle-aged or older dogs, and may be either idiopathic or due to interstitial tumors on the testes. Dogs with tumors may often have ring-like growths around the anus or perineum. Dogs may also exhibit behavioral changes, such as aggression and an increased sex drive. Most conditions are responsive to castration, which is the recommended treatment. Similar disorders involving non-inflammatory hair loss can also be found in females and non-castrated males of any age. This is usually referred to as Alopecia X. This disorder isn’t fully understood, but it’s believed that an imbalance in the adrenal sex hormones disrupts the hair cycle. Alopecia X is more common in some breeds. Most cases are idiopathic although versions of the disease can occur with endocrine disorders like Cushing’s disease and hypothyroidism.

In dogs, elevated male sex hormones, called androgens, are associated with non-inflammatory hair loss, and oily or discolored patches of skin. Hyperandrogenism is a disease that occurs from elevated hormone levels in non-castrated males. If similar symptoms occur in females or dogs that are neutered, it is called Alopecia X.

These abnormal symptoms should be evaluated by a veterinarian, especially if your dog is an uncastrated male.

• Hair loss focused on the hind quarters
• Dry or bleached hair
• Scaly or oily skin
• Hyperpigmentation (areas of dark colored or brown skin)
• Masses on the testes
• Aggressive behavior
• Increased sex drive

Types

Several types of elevated hormones can cause similar symptoms.

• Hyperandrogenism – occurs in uncastrated males
• Hyperestrogenism – elevated estrogen levels can also cause symptoms of hair loss (more common in unspayed females)
• Alopecia X – a generic term for non-inflammatory hair loss that is probably caused by a complex hormone imbalance; a number of different names have been used to describe this disease based on treatments, including growth hormone responsive alopecia, melatonin responsive alopecia, and Lysodren responsive alopecia

Some conditions can make elevated sex hormones more likely.

• Lack of castration in males
• Tumors of the testes
• Tumors on the ovaries (more commonly causes hyperestrogenism)
• Endocrine disease (Cushing’s disease - atypical, hypothyroidism)
• Breeds that are more likely to develop Alopecia X (Miniature Poodle, Pomeranian, Chow Chow, Akita, Samoyed, Keeshond, Alaskan Malamute, Siberian Husky)
• Idiopathic

The veterinarian will perform a thorough physical examination and evaluate your dog’s symptoms. If your dogs is an uncastrated male, hyperandrogenism will be suspected, especially if the sexual organs or tail gland is enlarged. In most cases blood and urine tests will come back normal. The veterinarian will check for signs of inflammation which could suggest a differential diagnosis, and may evaluate a cellular culture microscopically to check for fungal or bacterial infection. X-rays or ultrasound could be ordered to identify tumors on the testes.

The veterinarian will try to eliminate other potential causes of alopecia, especially if your dog is not a castrated male. This includes an ACTH stimulation, a specialized endocrine test to check for Cushing’s disease and thyroid imbalance. Elevated progesterone levels after testing can sometimes indicate an adrenal sex hormone imbalance. Sex serum levels will be tested also. X-rays may be needed to check for glandular tumors. Breed can be relevant for cases of Alopecia X, so the veterinarian will need to know your dog’s family history.

Castration is the first treatment for hyperandrogenism. Cancerous tumors on the testes will be removed at the same time. Male dogs usually have this procedure on an outpatient basis. Your dog will need to limit exercise for several days and may have a swollen scrotum. If there are stitches, you will need to return to have them cut, and the vet may want a post-operation check-up anyway. The procedure could be more extensive depending on the placement of testicular tumors.

Many symptoms are responsive to castration. If the problems returns however, or if your dog is already neutered or female there are some other treatment options. Idiopathic cases of Alopecia X are often treated with the hormone melatonin. This is effective in about 40% of cases, but it may take 3 months of treatment for your dog’s hair to regrow. Medroxyprogesterone is another hormone that can sometimes be more effective, but it also has more negative side effects than melatonin.

Conditions that are caused by a form of Cushing’s disease are often responsive to Lysodren (mitotane). This is a more drastic treatment with potential side effects, but if excess cortisol precursors are stimulating sex hormone production, it can be effective. Other options your vet might recommend for severe or stubborn cases include growth hormone administration and trilostane, another medication used to treat Cushing’s disease.

Many cases of hyperandrogenism are responsive to castration and your dog will make a full recovery. Some dogs may need retraining after surgery to help modify aggressive behaviors that have become habitual. 

Some cases of Alopecia X are also responsive to treatment, but the cause of this condition is less well understood and can be harder to pinpoint. The symptoms are mainly cosmetic, however, and can be managed even if hair loss persists. Frequent bathing and the use of anti-seborrheic shampoos can help to improve skin health. Antibiotic or antifungal creams will limit the chance of a secondary skin infection. This may be necessary even while your dog is taking medication as most drug treatments take a while to produce an effect. Always discuss the side effects of any treatment plan with your veterinarian.