Superficial Necrolytic Dermatitis in Cats
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. Fortunately, this disorder is uncommon in cats.
Superficial necrolytic dermatitis is uncommon in dogs and rare in cats. If you would like to learn more about how this disease affects dogs, please visit this page in the PetMD health library.
Symptoms and Types
This skin disorder will generally affect the cat's legs and torso, causing:
- Scabs
- Redness
- Alopecia
- Ulceration
- Scaling of skin
Causes
In cats, superficial necrolytic dermatitis has been associated with pancreatic cancer, liver disease, and intestinal lymphoma (cancer of white blood cells in the intestine). Other causes include a nutritional imbalance due to a lack of amino acids or a deficiency in the cat'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 cat, 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 levels of bile acids in the blood, high plasma glucagon levels, low amino acids, and high insulin. 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 an examination.
Treatment
Your veterinarian will treat the underlying disease process if possible, and will prescribe the appropriate medicine to treat the cat's symptoms. Most cats 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.
Cats 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 cats with 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 cat feel more comfortable.