Allergic Skin Disease

Allergies and allergic skin disease are by far the most common problem we see at our practice here in Hudson. In Florida, due to the hot, moist climate most months of the year, allergies and their dermal manifestations are worse than they are in any other area of the country.

Skin Allergies in Pets

Allergies typically present in dogs and cats differently than they do in people. When we have allergies – such as hay fever – we usually experience head signs: itchy eyes, runny nose, sneezing, etc. We don’t usually get itchy skin except in the case of eruptive reactions secondary to food allergies.

However, in our pets the most common manifestation of ALL allergies is itchy skin. Different allergies tend to make the animal react in different areas, which we’ll cover shortly, but in general itchy skin is the most common symptom of all allergies in pets. Further, dogs and cats tend to react a little differently, but nonetheless skin is the most common area of reaction.

The 3 Main Allergies in Pets

There are 3 main groups of allergies in dogs and cats, and a fourth, more complicated form, also. The 3 different allergies we commonly see in practice are:
1.) Flea allergies;
2.) Environmental allergen allergies; and
3.) Food allergies.

Flea allergies are the most common allergy we see in terms of percentage of animals affected. More than 80% of small animals have some degree of flea allergies.

When dogs and cats have itchy skin secondary to fleas, it is not the bite of the flea that itches. That is, the area where the flea bit the pet is not usually the itchy area. Instead, dogs and cats have itchy skin secondary to flea bites because they are allergic to a protein in flea saliva. When the flea bites the pet it leaves behind a small amount of saliva, and this triggers an allergic reaction in the pet.

So when we see itchy pets with fleas we talk about it in terms of an allergy, not a physical irritation. Flea allergies tend to present as itchy skin over the rump and along the top of the back. You can read more about Flea Allergy Dermatitis here.

The second allergy we see is allergies to environmental allergens, such as pollen, mold and dust mites. This allergy in small animals is termed Atopy, or Atopic Dermatitis, and in terms of sheer numbers of cases we see, it is the most common problem in our practice. Due to the high quality flea products available today, this is actually a much more common problem than flea allergies.

Atopy is primarily an inhalant problem. That is, although we sometimes call this a grass allergy due to pets commonly being allergic to grass pollen, it is actually a problem of the pet breathing in these allergens, and then having itchy skin secondary to the ensuing allergy.

Whereas we breathe in pollens and molds and get hay fever signs, our pets breathe in these allergens and get itchy skin. That’s why this problem is just as prevalent in indoor dogs and cats as it is in those that go outside.

Atopic dermatitis tends to present as itchy skin on the belly, in the groin and inner thighs, and in many breeds of dog as itchy feet. So when you see your dog licking his feet incessantly that’s not just a nervous habit – it’s probably a response to an allergic reaction. You can read more about Atopic Dermatitis and how to treat it here.

The third type of allergy we see is food allergies. The most common thing we hear when we diagnose a food allergy is: “Well I know the problem isn’t his food because I haven’t changed his diet in months.” Unfortunately, that’s the most common time to see food allergies.

Food allergies don’t manifest when the pet is first introduced to a new food. Food allergies take months to years to develop, and so most people don’t ever think that the food could be the issue. The most common time to see a food allergy is around 6 months after the new food is first introduced, but it could be as much as several years later that a food allergy manifests. You can read more about food allergies and how to diagnose them here.

And that fourth, ethereal skin allergy that’s so hard to diagnose? True contact allergies. Pets can be allergic to things they touch or rub against, such as carpeting, furniture, and even grass or weeds outside. But the only way to diagnose a contact allergy is to keep the pet off of all potentially allergenic materials, which essentially means keeping him in a stainless steel cage (no towel or blanket) or a tiled room for a couple weeks to see if the skin clears. Because of the difficulty in making this diagnosis it is most likely often overlooked.

Skin Reactions

Dogs and cats tend to react a little differently when they have allergic skin disease. While both animals get very itchy skin and tend to chew or lick a lot, dogs tend to get secondary skin infections caused either by bacteria (Staph pyoderma) or yeast (Malassezia dermatitis). These secondary infections must be treated separately from treating the underlying allergy in order for the dog to clear completely.

On the other hand, cats with skin problems don’t usually get secondary infections. Instead, they tend to present more with tiny scabs caused by an allergic eruption called miliary dermatitis. Because of the differences in manifestations, dogs and cats are treated a little differently for their skin allergies. Visit the individual allergy areas separately to find out how we diagnose and treat each of these allergies.