Sunday, March 25, 2012

So You Think Your Dog Has Allergies, Part 1: Symptoms and Types

When Maisy was just a wee thing, she began chewing on her legs. A quick internet search suggested that it might be food allergies, so I switched her food. And again. And again. What started as just a bit of itchiness evolved into almost a year of frustration.

As it turns out, the subject of canine allergies is complex, and internet advice is often simplistic and lacking vital information. That’s why I decided to tackle a three-part series on the topic. Of course, I am not a vet, so this is not medical advice. Instead, it is a sharing of information from one owner of a dog with allergies to another. If you think your dog might have allergies, I highly recommend you schedule an appointment with your vet because there are a number of other skin problems that can look like allergies but are not.

Signs Your Dog Has Allergies
So, what do allergies look like in dogs? Well, unlike in humans, dogs typically don’t have nasal congestion. Runny noses, sneezing, wheezing, or eye discharge may be a symptom of allergies, but it probably isn’t. See your vet. Instead, dogs with allergies are itchy. What you will see is excessive scratching, licking, and chewing. This typically happens on the feet, face, and groin, but may show up anywhere.

Unfortunately, these behaviors can result in secondary problems, most often skin infections or ear infections. Before we got a handle on Maisy’s allergies, she chewed off most of the fur on her front legs, and had some scabs. It was pretty ugly, actually, and we did need to treat her with antibiotics to help clear it up.

Her left leg is bare and the skin is being damaged because she was chewing it so much.

Allergy Cause #1: Flea Bites
The most common of these causes is flea bites. According to research cited in the April 2011 Whole Dog Journal article Itching to be Well by Nancy Kerns, approximately 40% of dogs have an allergy to fleas. Of course, if a dog is bit by a flea, it’s going to itch either way. However, a dog who is truly allergic will have an overreaction. If you have found only a few fleas, but your dog has widespread redness- or worse, oozing sores- it’s likely he’s allergic. The bad news is that dogs who suffer from a flea allergy tend to get worse throughout their lives.

Allergy Cause #2: Environmental
Environmental allergies happen when a dog has an itchy reaction to something he has either inhaled or been transcutaneously exposed to. Things like mold, dust, and pollen are common, although poor Maisy is also allergic to- are you ready?- human dander. (Yes, that's possible. Yes, I cried when I found out.)

According to the Whole Dog Journal article, approximately 10% to 15% of dogs have an environmental allergy. 80% of these dogs will also have a flea bite allergy (for once, Maisy has beaten the odds!). If your dog has an environmental allergy, it’s highly likely you’ll know it while he’s still young- 75% of dogs will show symptoms before three years of age, although the first year tends to be fairly mild.

Allergy Cause #3: Food
Food allergies are actually quite rare, although the exact prevalence is contested. A conservative estimate is that 1% to 5% of dogs have food allergies, possibly up to 10%, but the Whole Dog Journal reviewed research that suggests up to 43% of dogs are sensitive to some food item. 43% of these dogs will also have another type of allergy.

Food allergies are unique in that they typically affect more than just the skin. 10 to 15% of dogs will also have gastrointestinal symptoms like diarrhea, vomiting, excessive gas, and cramping, and a dog with food allergies might also be affected in the respiratory tract or central nervous system. This means that diagnosis can be tricky; you definitely want to visit your vet.

Although food allergies can begin at any time in life, generalized itchiness that begins before six months of age is very probably caused by food. This is absolutely true for Maisy- she was right around five or six months when we first noticed the excessive itching. Of course, this was complicated by the fact that her birthday was in the fall, meaning that Maisy hit her six month birthday at the height of allergy season- the spring.

So, how did I determine what her allergies were? Well, it was an incredibly frustrating process. I learned a lot during it, though, and in my next post, I’ll share some information that will helpfully make the process easier for you. Part three will discuss some of the treatment options available.

Until then, I’d love to hear from my readers. Do your dogs have allergies? Do you know what they’re allergic to? What symptoms did they have?


K-Koira said...

My dog Koira has a contact allergy to metal, which was a nightmare to figure out. She had horrible redness, scabs, and itching on her neck, and the ends of her ears were literally falling off. She also broke out in hives randomly, had bad dandruff, and would get covered in red non-hive rashes as well.

The answer finally came one day from a friend's suggestion of a metal allergy (we had already tried food eliminations, and the allergy symptoms had persisted through all seasons with no change, which ruled out most environmental allergens). I immediately removed all metal from collars, all metal bowls, and all contact with metal, and I watched my little girl's neck heal up and ears recover.

Sara Reusche said...

Layla's allergic to:

Brewer's Yeast
Dust mites
Candida Albicans
Johnson Grass
Russian thistle
Marsh Elder
Poverty Weed
Orchard grass
some metals (she's okay with her stainless steel food bowl, but not with the metal from collar tags)

We've tried various things, but mostly rely on avoidance where possible and lots of baby wipes/baths during allergy season. Hyposensitization shots caused her reactivity to escalate, and she became horribly aggressive on steroids. She gets antihistamines when necessary (we alternate between chlorphenarimine and diphenhydramine). I can't afford Atopica, which makes me feel super guilty since it would likely help her.

She gets red, itchy skin, hives, and hair loss from her environmental allergies. Her food allergies cause ear infections and urinary incontinence. She eats a raw food diet (formulated with the help of our veterinarian) to avoid food allergens, because even commercial dog foods that don't contain any ingredients she's allergic to cause her to react allergically.

Crystal Thompson said...

Metal would be SO hard to figure out! One of my kitties seems to have a problem with plastic bowls, but nothing like what you're describing, K-Koira!

Sara, the fact that Layla reacts allergically to kibble that has "safe" ingredients is sad/scary. Clearly it's due to contamination from previous kibbles... which suggests a lack of cleanliness or something.

Nola said...

My dog Nola has allergies to corn and soy. Truly a miserable processes figuring it out. She itched so bad she had to be kept inside most of the time to avoid infection and if she moved fast she'd open her scabs from itching so hard. It was a heartbreaking experience. She also had chronic ear infections and bad gas and loose poop. Took about 4 months from the time she started itching (at 6 mo) to the full diagnosis. I know make her food and am very VERY careful about what treats she can have

Crystal Thompson said...

Oh my gosh. Poor Nola! I'm so glad you've got it figured out!