Written by Dr. Sherry Weaver

I have two Shih Tzus -- one female and one male. They are brother and sister and are around three years old. I have a big problem with itchy skin. They are always scratching. I have tried about every thing: Benadryl®, steroids, bathing, sprays, etc. What else can I do for them? I even changed their food to Natural Balance® Allergy. I don’t want to keep them on the steroids, so I now give them the Benadryl® one to two times a day. I bought a supplement called Lipiderm I started them on this week. Any other advice would be nice.

Thanks,

Cheryl
Wichita, KS

Dear Cheryl,

Skin problems are among the most common things most veterinarians see (at least in the Southeast where I practice). When treating skin, you must be very organized and systematic. First you must eliminate secondary infections. These can be bacterial, yeast, or parasites. They can be treated with antibiotics, antifungal shampoos, and, if you are in a part of the country with fleas, (look for itching at the base of the tail) flea control products like Advantage® or Topspot®. Often it is a good idea to get a skin scrape to rule out mange (not so common in adults, but easier to treat than allergies). Quite often Prednisone is used during this phase for short-term control of the itch, but it should be used for only a short period of time.  Products such as Lipoderm also help with the itch somewhat. Once you have eliminated the infections, the real challenge comes… what is the allergy?

Allergies fall into 3 categories: (1) inhalant, (2) food, and (3) contact.

Inhaled allergies tend to be seasonal, so it doesn’t fit your pets’ profile. The few of them that are year-round can only be detected by skin testing at a dermatologist. Contact allergies can be more year-round, and it may be worth changing your laundry soap or eliminating any wool blankets. Food still seems to be the most likely allergy you face. Food allergies tend to have several things in common: They happen year-round, they don’t always completely go away with prednisone, they tend to be feet and ears, and they start very young in life. I suspect your vet recommended the food you are using to rule out food allergy. Since I am not familiar with the brand of food, I would recommend checking the label to be sure it does not contain chicken, beef, corn, wheat, dairy, soy, or egg (common allergens in dog food) and that it is naturally preserved with Vitamin E and other natural preservatives. I tend to use Innovative Veterinary Diets® Venison and Potato or Eukanuba® Fish and Potato at my practice. There are recipes available if you want to cook your own hypoallergenic food. You may even want to try one of the “hydrolyzed” diets, where the proteins are so small the immune system can’t recognize them. (Science Diet z/d or Purina HA are two such foods). Many people are fooled into trying “all-natural” foods which claim to solve skin allergies. These foods only eliminate chemical allergens, which are only a small portion of potential causes, so they are not truly hypoallergenic.

To diagnose a food allergy, you feed a hypoallergenic food exclusively for 6-10 weeks.  If the itch goes away, it is a food allergy. If not, there is likely another allergy (unless there is still some infection present). One of the most common reasons for food trials to fail is “It was just a little cookie” or “Fluffy has to have her rawhide”. For a food trial to be successful, you must be strong. (Fluffy will thank you). Even the tiniest amount of allergy-causing food can start the whole itch all over again. At the end of the 6 to 10 weeks, if you were perfect and there is no improvement, it is unlikely to be a food allergy, and you can go back to normal food while you get inhalant allergy testing done. If there is improvement, the best way long-term to control the allergy is to stay on the hypoallergenic food. 

Inhaled allergies are the hardest to control. There is allergy testing available, just like in humans. It is long and complex, but sometimes gives us a piece of the puzzle or even a treatment plan. Most people control these with medications. Prednisone is usually very effective and cheap, but it prematurely ages a dog so shouldn’t be given long-term. Antihistamines are very safe and can be used long-term, but are often not extremely effective. I would recommend trying multiple antihistamines as they can work differently in different dogs. Cyclosporine is becoming a very popular method of controlling the symptoms of allergies. It is relatively safe long-term and is very effective. The disadvantage of cyclosporine is that it is very expensive, and it can take several weeks to take effect. For dogs the size of Shih Tzus, this may still be an economical possibility. I would recommend discussing all your options with your vet.

Dr. Weaver

About Dr. Sherry Weaver
Dr. Weaver graduated with honors from the University of Georgia's School of Veterinary Medicine.  She founded a state-of-the-art animal hospital, teaches pet care to children, and donates time and resources to rescue organizations. For her full biography, click here.

Note: The opinions and views expressed in the Ask the Vet articles are the result of Dr. Sherry Weaver's formal education and over 14 years in clinical experiences. Your veterinarian is the best source of information for your pet’s specific needs.