Degenerative Skin Disorder (Necrolytic Dermatitis) in Dogs

Superficial Necrolytic Dermatitis in Dogs

Superficial necrolytic dermatitis is characterized by the deterioration and death of skin cells. High levels of the hormone glucagon in the blood -- which stimulates production of blood sugar in response to low blood sugar levels -- and deficiencies in amino acids, zinc, and essential fatty acid are believed to play a role in superficial necrolytic dermatitis, either directly or indirectly.

Superficial necrolytic dermatitis is uncommon in dogs and rare in cats. If you would like to learn more about how this disease affects cats, please visit this page in the PetMD health library.

Symptoms and Types

This skin disorder will generally affect the dog's muzzle, paws, footpads, eyes, and genitalia, causing:

• Scabs
• Redness
• Abrasions
• Ulcerations/sores
• Pain while walking
• Cracking of the skin and footpads
• Hyperkeratosis (thickening and hardening of the skin)

Causes

Superficial necrolytic dermatitis has been associated with a nutritional imbalance due to a lack of amino acids or a deficiency in the dog's essential fatty acids and zinc; or metabolic abnormalities caused by high serum glucagon levels, liver dysfunction, or a combination of these conditions.

The skin condition is rarely associated with a glucagon-secreting pancreatic tumor, or long-term phenobarbital and phenytoin medication, which is used to treat seizures.

Additionally, superficial necrolytic dermatitis is generally an outward symptom of advanced hepatic disease, or of coincident hepatic disease and diabetes mellitus.

Diagnosis

Your veterinarian will perform a complete physical exam on your dog, including a biochemical profile, a complete blood count, a urinalysis, and an electrolyte panel. You will need to give a thorough history of your pet's health, onset of symptoms, and possible health conditions that might have precipitated this condition.

Some blood tests may return with abnormal results, such as high bile acids in the blood, high plasma glucagon levels, low amino acids, and high insulin levels. Sulfobromophthalein sodium (BSP, excreted in the bile) levels may also increase to abnormal levels in the blood.

X-ray and ultrasound imaging usually are not helpful in diagnosing glucagon. However, an ultrasound may reveal advanced liver disease. Skin biopsies (tissue samples) are crucial for making a correct diagnosis, but only early lesions are useful for examination.

Treatment

Your veterinarian will treat the underlying disease process if possible, and will prescribe the appropriate medicine to treat the dog's symptoms. Most dogs can be treated on an outpatient basis, but in some cases, hospitalized care will be necessary. Outright liver failure should be treated with supportive care.

Dogs with glucagon-secreting tumors can be cured with surgery, but the tumors will typically spread quickly, before surgical intervention can reverse their progress. Most of these cases are associated with chronic, irreversible liver disease.

Living and Management

Unfortunately, most dogswith this disease will also have a severe internal disease with a poor prognosis. A specially-formulated prescription shampoo can help to remove the crusts and may make your dog feel more comfortable.