Treatment of Itchy Dogs

It's important to remember that skin disease is almost always a secondary condition. In order to provide the dog relief, you need to fix the primary problem.

Once I've ruled out metabolic diseases, the first thing I always do is put some flea medication on the dog. Many people don't know that it only takes 1 flea for a dog to have a full-blown reaction. Flea saliva has more than 17 different allergens.

The next step is to change the pet's diet. Most dog foods contain beef in some form or another. It's also known that many dogs that react to beef will also react to venison. It's important to feed the dog a single protein source, so I try to steer people toward duck and potato, fish and potato or something exotic like ostrich or kangaroo. However, the best diet is a modified protein diet such as Hill's Z/D. It's also important to feed the dog only the new diet for a minimum of 8 weeks. If the dog gets anything else, it may make ruling out food allergy more difficult.

Finally, I try antihistamines. There are at least 5 different antihistamines that have been shown to be effective in the dog. Before you try any antihistamine in your dog you need to speak with your veterinarian. I will even add omega-3 fatty acids or fish oils to the mix in extreme cases.

This is about as far as most general practitioners can take a case. If these steps fail, the next step is a veterinary dermatologist. These specialists can test your dogs specific allergies and make a vaccine to help control your dog's allergy.

Many veterinarians will attempt to control itchy dogs with steroids. This is great for business. The dogs get better and the clients love the convenience. Remember, though, most skin diseases are secondary problems. Masking the signs of allergies doesn't fix the primary problem. Also, just like the antihistamines, the steroids will eventually fail. Plus, excessive steroid therapy has the added effect of leading to liver failure, urinary tract infections and stomach ulcers.

Dogs that Scratch

Itchy dogs probably account for about 25% of the dogs I see in practice. It's a very common problem that you think you have have a simple solution. If all these dogs have this problem, then why can't we figure out what the problem is? Well, actually, most of the time we can. It just takes patience and money. Most of my clients only come in the exam room with one of them....

First, let's look at what diseases will make a dog itch. Basically, you can divide most itchy dogs into 4 broad categories: 1) Fleas (and other external parasites), 2) Food Allergies, 3)Metabolic Diseases, and 4) Atopy (or inhalant allergies).

We'll leave fleas out of the discussion for now. Since I've beat the flea topic to death lately, let's start with food allergies. Many dogs I see with food allergies tend to have itchy feet and ears. However, they can present with any type of scratching. The good news about food allergy is that in theory it's easy to fix. Switching the dog over to a new protein source, or a specialty diet, such as Hill's Z/D should help the dog. However, switching the dog over to a protein source that the dog has never seen before can be difficult. Many dog foods that say "Lamb and Rice" on the label also contain other protein sources. I often tell people not to open the bag before they bring it to my clinic for me to read. This allows them to return the food if its not right. (Of course, it would be easier if they just bought the right food from me, but some people really think I'm trying to overcharge them. I promise most practices make so little off of dog food, they would rather it was easier for you to buy it somewhere else.)

Although rare in my experience, metabolic diseases such as thyroid and adrenal gland disease can cause itching. Most of these dogs also have other clinical signs, but many times the owners (or their veterinarians) don't recognize them. In dog's that are unresponsive to initial therapy, I always recommend a full blood panel.

The last area is the most broad, least understood and the hardest to treat: Atopy. The term atopy refers to inhalant allergies. In most cases, this is going to require a referral to a veterinary dermatologist.

Tomorrow we will discuss potential treatments. As always, though, you should speak with your veterinarian about your dog's specific condition.

Pyrethrin Poisoning in Pets

This weekend at my emergency clinic we almost had another casualty to the “Frontline and Advantage as too expensive for me” excuse to save a couple of dollars. A client put an over-the-counter flea medication on her cat. About an hour later, the cat was having a seizure and was unresponsive. A night in the hospital and a couple of hundred dollars later, we were able to send the cat home. Not all of those patients are so lucky. I found a great website that describes what pyrethrins are, how they work and why you probably shouldn’t use them on any of your pets.

http://pmep.cce.cornell.edu/profiles/extoxnet/pyrethrins-ziram/pyrethrins-ext.html

I know we talked about this before, but I wanted to let people know that there are at least 2 new products on the market.

Promeris: It’s a completely new compound that works on both dogs and cats. Since it’s labeled for killing fleas for more than 4 weeks, there should be very little problem with the product being overwhelmed by a large infestation when used monthly. (www.promeris.com)

Comfortis: It’s a monthly pill that kills fleas. One of the most common reasons given for flea medication failure is incorrect application of the product. Oral administration should fix that problem. The major drawback of this medication is that is doesn’t work on ticks, so you would need to use an amitraz collar alongside the monthly pill. (www.comfortis4dogs.com). It would be great if someone mixed this product with a monthly heartworm preventive.

Flea season has already arrived in parts of the South and it won’t be long before its warm enough for these little pests up North. Now is the time to start your flea control program. Remember, only 5% of the fleas in an environment are in the adult stage. Or, for every 5 you see on your dog, there are 95 in your carpet!

http://frontline.us.merial.com/fleas/sub3_flea2.asp

Furunculosis

Furunculosis in the dog is a painful disease which stymied the veterinary profession for years. Most of the time, the disease affects adult German Shepherds. The treatment of choice, at one time, was massive doses of steroids and antibiotics. The steroids provided a double whammy. First, the steroids caused all the usual side-effects: excessive urination, excessive water consumption, liver failure, gastro-intestinal trauma, etc. Second, in a breed that was already prone to hip dysplasia, the steroids hastened the painful degeneration of these already damaged joints.

Since most dogs with furunculosis had a horrible infection, the next stage in the treatment of this disease was to remove the tail. The theory behind this treatment was that if the skin had access to open air, then bacteria would have a more difficult time setting up an infection. That treatment option very rarely went over well with owners, but a lot of dogs got better, so it was often done as a treatment of last resort.

Next on the list of treatments was cyclosporine. Since this medication, like most of the medications we use in veterinary medicine, came from the human medical field, it was expensive. The cost of cyclosporine has come down dramatically since it was first used and now is a standard of treatment for dogs with furunculosis along with surgery to remove the diseased tissue.

A recent study just came across my desk (Preoperative immunosuppressive therapy and surgery as a treatment for furunculosis; Klein A, et. al; Vet Surg 2006; 35:759-768). In the study they compared two different immunosuppressive therapies along with surgery to determine how effective therapy might be in curing this disease. The authors were able to conclude that surgical therapy combined with pre-surgical medical therapy can be effective in preventing recurrence of furunculosis.

The study does have some limitations. For starters, it was a retrospective study. This means they looked up cases that had been treated without regards to a standard protocol. There also was no control group to compare with the treated groups. These are significant drawbacks, if we were looking for definitive proof. However, since many dogs suffer from this disease and treatment can be frustrating and expensive for the owner (not to mention the dog!) it makes sense to attempt these therapies while we wait for a definitive cure.