Pets ::

Itchy Cat and Dog Tales
Appearance, causes, treatment, and prevention of canine and feline skin diseases.

by Dr. Kelly Byam

Living with a pet that is chronically itchy is extremely frustrating. Your pet may lose its hair, develop sores on its body, and look miserable. Many people struggle for years trying different shampoos, ointments, antibiotics, but never come any closer to stopping the pruritus (itchiness) that makes their beloved pet look and feel so bad.

The itchy cat or dog can also be a challenge for veterinarians, whose job it is to determine the cause and treatment for pruritus. Allergies, infections, parasites, and hormonal imbalance are all possible causes of itchiness.

Allergic Dermatitis Allergic dermatitis falls into four categories: flea allergy, food allergy, atopy (reaction to inhaled allergens, similar to hay fever in humans) and contact allergy. Prevention consists of strict flea control on the pet in and around the house. There are several good topical flea preventives such as Advantage®, Advantix®, and Frontline Plus®. Program® is an oral flea preventive, and Capstar® is another oral flea treatment that kills all fleas, but only works for one day.

Food allergies can sometimes be an unrecognized cause of pruritus. Over time, the proteins found in common food ingredients can cause allergies to develop that manifest as a skin problem. Sometimes a hypoallergenic diet will be prescribed for up to ten weeks to see if the itchiness disappears.After the trial is over, the pet may be “challenged” with the original diet to see if the problem recurs. There are many excellent hypoallergenic diets on the market today, and nutritional supplements are often given.

Atopy is an allergy to inhaled allergens and can cause itchiness, skin infections, ear infections, and licking or chewing of the feet. Most animals will be seasonally pruritic, being worse in the spring and summer, or in the fall and winter. Treatment includes antihistamines and/or a series of weekly injections of a low dose of allergen for an entire year.

Contact hypersensitivity is relatively uncommon, but it can be seen when an animal is allergic to a product to which it has been exposed, such as perfumes, shampoos, carpet or carpet cleaner, and plastic food dishes. Diagnosis is based on a thorough history and physical exam, and treatment consists of removing the offending allergen from the pets environment.

Infectious dermatitis
Skin infections can cause varying degrees of pruritus. Treatment consists of antibiotics or medicated shampoos, as well as topical preparations.

Fungal infections can also cause pruritus. The most common fungal infection is caused by yeast, and the second is known more commonly as ringworm. Various treatments can be difficult and include vinegar baths, antifungal shampoos and ointments, or expensive oral antifungal medications.

Some deep fungal infections can cause skin infections, but these problems are not often seen in California, and are more commonly seen along river valleys in the Midwest and southern states.

Parasitic infections
Parasitic infections are caused by mites, biting flies or fleas, ticks, lice, and skin migrations of internal parasites.

Demodex mites are a normal inhabitant of the skin, but they can spread out of control in young or immune-suppressed animals. Treatment is any combination of medicated dips, topical ointments or oral medications.

Sarcoptic mange (also known as scabies) is an extremely pruritic disease, and is difficult to diagnose. Treatment in animals can consist of medicated dips and or medication administered orally or by injection, or by the use of a topical product called Revolution®.
Biting flies and other biting insects can also cause pruritus. In the event of bee or wasp stings, the allergic component can cause hives and facial swelling. Treatment consists of antihistamines and steroids. Good environmental control is essential for prevention of this problem, just as it is in the case of fleas.

Hookworms and roundworms can have skin migrations, and will leave red lines in the skin where they travel. Treatment is symptomatic, and worming, as well as environmental control (picking up feces daily) is advised.

Hormonal imbalance
Hormonal disorders such as hypothyroidism, Cushings disease and sex-steroid linked dermatitis are also causes of pruritus. Treatment of the dermatitis is usually unnecessary if the underlying cause can be treated.

There are many conditions, some life-threatening, some debilitating, and some merely uncomfortable, that cause itchiness in your pets. Only a few of the most common causes have been discussed in this article.

The most effective means of early detection and prevention and treatment of primary or secondary skin disease is regular veterinary check-ups. Puppies and kittens should be seen monthly until about six months of age, and then annually thereafter. Geriatric animals should be seen at least twice annually, or more often if recommended by your veterinarian.