Flea Allergy Dermatitis

Fleas can cause a number of health problems for your pet. But one of the bigger one is related to allergies. The technical name is flea allergy dermatitis, but essentially it involves hypersensitivity to flea bites. Some pets simply are allergic to the chemical compounds that exist in flea saliva. Fleas have a number of different things in their saliva that are designed to prevent blood from clotting while they are feeding off the animal. Your cat or dog may have a reaction to this, which makes it all the more important to get rid of the fleas that are causing the allergic reaction.

Flea Allergy Dermatitis Symptoms

So how do you know if your dog or cat has flea allergies? Your pet will feel it with an intense itching,. More so than a flea bite would feel like without the allergy. This usually causes them to obsessively bite and scratch at the area that is affected.

You should check the hair of your animal for any thinning spots – usually this will show up around the base of the tail, because that is where a lot of the flea bites are concentrated. You can be sure that this is being caused by fleas by looking for the tell-tale signs – comb through your pet’s fur, and you will usually find a flea or two. If not, you will find little black specks that turn red if you get them wet.

they are the feces of fleas, and because they are dried blood they will show up as red when you put water on them. If the allergies are severe, you will see hair loss on various places around the animal and also inflamed red spots. If you still aren’t sure, your vet can give the animal a test to determine whether these symptoms are being caused by flea allergies or not. There are other things besides an allergy to fleas that can cause this (animals have a surprising number of skin conditions they can be subject to).

What to do about it

If your pet has flea bite hypersensitivity, then you’ll need to do something about it. You shouldn’t just let the animal suffer with this. If your pet is allergic to flea bites, it borders on cruelty. The first thing to do about this is to exterminate the fleas that are causing the problem in the first place.

This guide gives you a number of tips on how to do this. So I won’t rehash them here (see information on natural flea control for a number of home remedies). But the one particular thing you should keep in mind here is that focusing on eliminating the fleas from your pet’s environment is most important in this case. A flea control product is a must, but you can’t just rely on that alone like other pet owners can.

You’ll have to go further and try to prevent your pet from having contact with fleas, period. Why? Because most flea control products work by poisoning the flea AFTER they bite your pet. If your pet has severe flea allergies, this won’t be enough – the saliva will already come in contact with them. So you’ll need to try to get fleas out of any environment your pet is going to be in. This means supplementing the flea medicine with vacuuming or other methods used to reduce the flea population. You may also have to control where your pet goes if it’s a severe cas. Frequent contact with other animals that you don’t own will mean frequent contact with fleas as well. And that can enhance the flea bite allergy.

Does your pet catch fleas despite the application of insecticide?

Modern insecticides are effective and the spot-on (pipettes) sold at the veterinarian are of good quality with little toxicity. However, even the best insecticide has limits, all the more so in allergic animals.
 The first reason is often the quality of the application . Contrary to popular belief, the product should not be applied to 1 cm of skin or hair. Otherwise a good part of the product slides on the coat and is lost. There should ideally be two for the applicatio; one that holds the animal and spreads the hairs in the region of the neck to make a line. The second that applies the product to the skin without causing it to overflow onto the hairs. It is usually necessary to repeat the maneuver several times (3 to 4 lines are often necessary). 

The second reason is related to the biology of fleas . The infestation is mainly by the environment with young fleas , and no current insecticide is repellent or active enough to prevent the first bite, even if the flea will be killed a few hours later. This is particularly annoying in allergic animals. 

The third reason is “statistical”: the monthly products are 99.5% active at the start and still 90-95% active the last week of effectiveness. During heavy infestation the number of fleas that hatch can be several thousand at the same time. With an activity of 95% there are potentially fleas remaining on a perfectly treated animal.

Do not hesitate to seek advice from your veterinarian to determine the best product suitable for your animal and its lifestyle.


Hello there. My name is Erkan. I am an engineer and very curious. I do not like fleas, so I will explain all the methods of how to get rid of fleas.

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