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Wednesday, January 7, 2009

Allergic To Flea Prevention?

I'll get back to "Controversy Week" tomorrow, but first here's a question I received from Terrald.

I'm about to be moving in with some relatives that have a cat. It seems to me that i am not allergic to cats themselves but more like the frontline or advantix used on the cats. Have you ever heard of such a thing before? mind you i do know that you're a veterinarian not a human allergist. so my major question is: is there something else that can be used to help with fleas in a comparable manner?

First let me state that I am a veterinary doctor, and am not the best source for human medical issues. However, there are a few things I know that might be able to help with this.

The antiparasitic components in Frontline and Advantage are different from each other. K9 Advantix has the same ingredient as Advantage, imidacloprid, but also adds permethrin to affect ticks. Permethrins are toxic to cats if swallowed, and therefore should never be used on felines. Imidacloprid is perfectly safe to dogs and cats. Frontline uses fipronil. Neither imidacloprid or fibronil is known to cause reactions on dogs and cats and both have been extensively studied. Rare reactions might be possible, but would be limited to localized irritation. K9 Advantix has been known to cause localized irritation to the skin that causes itching and redness, though this is very uncommon, and always is self-limiting within a few days. Both imidacloprid and fipronil are patented, and you won't find these components in other products. Most over-the-counter flea preventions use pyrethrins, which are in the same category as permethrin, or similar products. These products are more likely to cause toxicities and irritation, and are not anywhere near as effective as the products sold by veterinarians.

Most topical flea products work with similar principals, though their effectiveness varies extensively. Generally they affect a flea or tick's nervous system, causing various degrees of muscle contraction leading to paralysis and eventually death. The products have been designed to affect neurotransmitters only found in certain insects and arachnids. These ingredients should have no affect on humans, as we do not have the neurotransmitters they work on.

The carriers can cause local irritation in isolated cases. A carrier is the liquid component in which the actual flea product is included, and is the method by which the product is applied and distributed over the pet's body. A reaction is more likely to be due to the carrier rather than the antiparasitic product itself. If there is a reaction, it will be in the first 24-48 hours after application. Most or all of these products are completely absorbed into the skin within 24 hours of application. This means that if you contact the skin more than 24 hours after application, you will get minimal or no flea prevention on your own skin. Even permethrin is considered safe to cats once it has been fully absorbed in 12 hours.

So back to Terrald's question. First, I would be very careful in trying to determine what you are actually allergic to. Some people with cat allergies have a stronger reaction to some cats than others. The cat's dander is usually the problem, and the amount of dander can vary between individuals and breeds. You should also determine what kind of "reaction" you are having. Any of these flea products would cause localized irritation where you touched the cat. Sneezing, itchy eyes, or generalized itchyness are not normally signs of a reaction to a topical product. I would lastly recommend discussing this possibility with your physician or an allergist. If you don't think you're having a serious problem, try applying a small amount of Advantage or Frontline to your skin and see if you have any problems. Be very careful before you try this, as I don't want you to have a serious problem! Try it at your own risk and based on what you've felt so far. If full strength product applied directly to your own skin causes no problems within 24 hours, then it's not the product. I've gotten all of these products on my own skin numerous times and never had a problem.

There really aren't better flea control products out there. Environmental products for the house and yard (sprays, foggers, etc.) are best used as part of a comprehensive flea control program, and not by themselves. Flea collars simply are not effecitve, and in my opinion are a waste of money. Flea shampoos and dips give no residual protection, which is really what you need. The current veterinary topical products really are the best things out there.

Hope this helps! Back to the controversies tomorrow!!