ALLERGIC SKIN DISEASE and FLEA CONTROL
North Florida Animal Rescue * Wellborn, FL * 386-963-1354
Tracie A. Daniels, DVM
Allergies are common to us all, including our pets. For many humans some types of allergies
produce common signs including sinus congestion, headache, and itchy red eyes. Other people
can’t eat shellfish or peanuts or wheat, and have a range of signs from intestinal problems to
“hives” to severe respiratory and breathing problems. Still other allergies exist to bug bites or
insect stings, and “contact” allergies include things such as the formation of itchy, red skin with a
rash after using a new laundry detergent. Obviously, the allergic reaction is widespread and
complex.
Our pets are no different, except they can’t verbally tell us what’s wrong. Common signs of
allergic disease in pets may include hair loss, crusting and scaling skin lesions, itching,
“overgrooming” in cats, ear infections, inflammation and redness of the feet / “paw licking” in
dogs, and secondary bacterial skin infections such as Staph. Intestinal upset from foods, weight
loss, and IBD (inflammatory bowel disease) are other possibilities.
Figuring out allergic skin disease can be a long process, and can be difficult since an individual
pet may have one or more allergies at the same time. To try to simplify the discussion, let’s
break pet allergies up into several categories:
1) “Atopy” or atopic dermatitis, which includes allergies to pollens, trees, grasses,
weeds, etc. This is often the one humans think of when we think of allergies.
2) Food allergy, which is an adverse reaction usually to a food protein source
3) Flea allergy, or FAD (Flea Allergic Dermatitis), which is allergy to flea bites (flea
saliva is thought to be the allergen)
4) Contact allergy, such as eruption of skin problems in contact with an allergen (new
detergent on a blanket, harsh floor cleaner on the paw pads, corals in the Fla Keys)
What signs do pets show us to help know which type they have? It varies tremendously. Much
has been written about where the hair loss is on the pet, what environment they are in, and
other history from the owner. Trust the veterinarian to help you narrow down which type(s) your
pet may have.
For many allergies, treating the result of the allergy is enough to keep your pet comfortable. For
ear flare-ups, there are ear medicines. For skin itching and paw-licking, there are shampoos,
rinses, antihistamines, oral fatty acid products, and even occasional steroids to help ease the
itching. For secondary bacterial infections, there are antibiotics. For secondary yeast infections
of skin or ears, there are antifungal products.
For other allergies treatment is also aimed at prevention of the cause of the allergy, to include
flea and food allergies. For instance products that kill fleas, sterilize flea offspring, or products
that repel fleas are useful for animals with FAD. This category would also include eliminating
certain foods from a pet’s diet that cause the allergy (such as no corn products, or wheat, or
chicken), or placing a plastic cover over a mattress for a cat with house dust mite allergy.
Doing tests to discover what allergies your pet has can be a valuable tool if the signs progress
or remain chronic. Two types of tests are used: skin testing and blood testing. These can be
expensive but if the animal is severe enough the results might be helpful. Elimination diet
testing can also be useful, where a pet is placed on a new protein source for 8-12 weeks to see
if the skin responds.
What about an “allergy shot?” When people talk about this, they often mean giving the pet
an injection of steroids that stops the itching and redness. While these are usually effective to
some degree, there can be serious consequences to the pet over time if this is repeated. These
include liver problems, weight gain, and adrenal hormone issues. However, a true “allergy shot”
is an injection given at repeated intervals to a pet that contains small amounts of the very things
they are allergic to, based on allergy testing. In some pets (and people) this causes the body
not to be so sensitive to the allergens and may help ease the disease. Results vary. These are
called hyposensitization vaccines. There is another vaccine in this category that specifically
helps pets with chronic skin Staph infections.
THE KEY TO UNDERSTANDING MANAGEMENT OF ALLERGIES
Imagine that you are a dog or cat, and let’s assign a number to your itchiness. On a scale of 110, anything over a 3 causes you to physically scratch or lick the paws. Less than a 3, you feel
a little bit of an itch but don’t need to scratch. From 3-4 you scratch occasionally, 5-8 you
scratch often causing bumps and skin trauma, and 9-10 you scratch constantly and can even
bloody your skin if bad enough. Keep this in mind.
Perhaps your pet has a flea allergy with a score of 3, plus atopy (environmental allergies) with a
score of 4. While each one separately might not cause a severe problem, TOGETHER they are
a combined score of 7. Other animals have one single allergy that is tormenting them, such as
a flea allergy with a score of 8, or a Staph infection on their skin with a score of 9. This is how
you have to think of allergic skin disease, as a total problem. A pet may have only a small
single allergy or a complex group of many. No two pets are completely alike.
Our job is to decrease the itchiness and discomfort to a level where the pet is comfortable and
not traumatizing the skin. Each part of therapy (a shampoo, an antibiotic, a flea-killing product,
a hyposensitization vaccine) does its part to decrease overall itching. Since allergens vary and
pets’ responses to products vary, each animal is a puzzle that can take some time to solve.
Finally, realize that over time allergies change, and what caused itchiness three years ago may
not do so now, or a flea allergy may worsen over time.
FLEA ALLERGY AND FLEA ALLERGIC DERMATITIS
The saliva from flea bites can be a potent allergen. Don’t confuse having fleas with having a
flea allergy. There are millions of pets out there covered in fleas that hardly scratch and have all
their hair; we’ve all seen them. But if a dog or cat has a flea ALLERGY, that pet will go insane
getting every last flea off, and just one or two flea bites can send the pet into an itching hairpulling frenzy. The most common sentiment from owners is “Doc, my dog can’t have a flea
allergy, because he never has fleas.” Now you as a pet owner understand why this is NOT
TRUE. Controlling fleas for allergic pets can be a multiple-step procedure:
 Control fleas on the pet (topical spot-ons, oral medications, spray repellents)
 Control fleas in the home (vacuum, spray home once a month, get professional help,
use boric acid crystals / Borax in carpets before vacuuming (let sit for several hours)
 Control fleas in the outside environment (pick 10-20 spots where the pets lounge the
most and where flea larvae would thrive like cool shaded moist mulch, under trailers,
flower beds….spray these areas once a month, ask pest control for help)
Any break in this whole scheme can result in failure of the program and be the “weak link.” This
can be tricky when you live next door to 10 dogs with fleas, or in areas where wildlife or feral
animals live, and yes, it can be expensive. But don’t blame your topical spot-on or oral flea
product for not working when you have not addressed the whole flea environment. More fleas
live in carpets and in furniture than people realize, as eggs and young flea larvae! Yuck!