Acanthosis Nigricans in Dogs

Acanthosis nigricans is found in all breeds and ages of dogs. There are two types. In both types, this disorder causes an increase in the dark pigmentation of the skin. It is usually found in the folds of the skin, and other areas where there is friction.  Classic symptoms are typically present, making the diagnosis easy. Type one always is hereditary, being found most commonly and almost exclusively in Dachshunds.  This type is incurable. Type two is typically a result of another condition. Once the condition is identified, the acanthosis nigricans can be cured.

Acanthosis nigricans is a disorder in dogs, presenting itself as a dark hyperpigmentation to the skin. There are two different types, one breed specific, and the other occurring in all breeds, ages, and genders of dogs.

With both types of acanthosis nigricans, the following symptoms may be found in the “friction” areas of the dog, such as armpits and groin areas:

• Brown-pigmented, raised wartlike areas on skin, particularly in body folds
• Darkening of skin, becoming thickened, leathery, and hairless
• Greasy, crusty, foul smelling areas on darkened skin
• Itchiness
• Pain may be present in inflamed areas
• Patchy, lace like pattern of inflammation on skin

Types 

There are two types of Acanthosis Nigricans. Primary acanthosis is primarily found in Dachshunds (usually one year old or younger), but although rare, it can occur in any breed. This type of acanthosis is not curable but manageable. This type does not necessarily become inflammatory, and usually develops uniformly on the dog.

Secondary acanthosis (post inflammatory hyperpigmentation) is found in all breeds and all ages of dogs, especially in Cocker Spaniels, Pugs, and Dachshunds. This type of acanthosis is inflammatory and patchy, but curable once the cause is identified. It often begins with a lace like pattern.

Primary form

Hereditary is the primary form of acanthosis nigricans. The way that it is inherited is not completely known, but there is a theory that a recessive abnormal gene or multiple genes are inherited from at least one of the parents of the dog. This form is almost exclusively found in Dachshunds.

Secondary form

The secondary form is usually a result of an underlying condition such as:

• Yeast infection
• Bacterial infection 
• Hypothyroidism (overactive thyroid) 
• Allergic dermatitis (skin disease associated with allergies)
• Mange (mites)
• Obesity (causing excessive skin folds due to fat deposits)

Your veterinarian will review your dog’s history and perform a physical examination. Skin scrapings will most likely be taken from the affected areas to rule out any underlying conditions which may be causing symptoms. Impression smears may also be taken and examined under a microscope. Conditions such as malassezia dermatitis (dermatitis caused by a specific yeast) and staphylococcal pyoderma (Staph infection), as well as other bacterial and yeast infections may be discovered. Testing for adrenal disease and thyroid dysfunction may be performed in older dogs.

Primary acanthosis is not curable in Dachshunds. If the disorder is caught early enough, simple treatments may be sufficient to manage the condition, thus stopping progression. If there is progression of the disorder, more aggressive therapy will be necessary. In secondary acanthosis, once the underlying cause is identified, it will be treated and the condition will improve, curing the disorder.

Shampoo therapy 

Your veterinarian may suggest the use of an anti-seborrheic shampoo for frequent bathing of the dog. This regimen will be followed until the condition is resolved.

Topical ointments

Corticosteroid ointment may be prescribed. This ointment can relieve inflammation and itchiness of the affected areas.

Vitamin E

Using Vitamin E orally has been successful when combined with other treatments. It may help to decrease itching and inflammation in the dog. Since Vitamin E can be toxic in doses too large, also follow your veterinarian’s advice when using Vitamin E therapy.

Antibiotic therapy

Sometimes in severe cases, a bacterial infection will develop and an oral antibiotic will be prescribed. Sometimes injectable antibiotics are used as well. 

Weight loss

Weight loss in the dog will be recommended if the acanthosis is related to obesity. This will reduce the size and amount of skin folds your dog has, which will make it more difficult for the yeast or bacteria to grow.

Depending on the type of acanthosis nigricans your dog is diagnosed with will determine the type of recovery and management you can expect. The primary type requires special bathing and topical ointment therapy to manage the condition, since there is no cure. Making the decision not to breed your affected dog is recommended, since primary acanthosis is hereditary. If your dog is diagnosed with the secondary type, the cause will be determined and the necessary treatment that your veterinarian recommends should cure the condition. Always follow your veterinarian’s instructions when treating your dog if you are using antibiotic or topical ointment therapy. Not using the medicines as indicated may cause a reinfection of the affected area.