Tuesdays with Shlomo

Understanding allergies

Dr. Shlomo Freiman
March 26, 2024

Allergies can affect animals in much the same way they do humans. However, unlike humans, they can’t tell their healthcare providers what kind of unseen symptoms they might be experiencing, what new food they ate, or whether they’ve run through any tall grass recently.

In this edition of Tuesdays with Shlomo, Dr. Shlomo Freiman offers a simple, straightforward framework for how to think about pet allergies, along with tips on how to see the signs of allergic reactions, how to limit your pet’s exposure to allergens, and how to know when it’s time to see a vet. He also discusses some eminently practical matters, like how to tell if your pet is scratching itself too much, and how frequently you should be bathing your pet.

Read on for an enlightening discussion of an often overlooked topic in pet care, along with lots of useful information about when a sneeze is just a sneeze, and when it’s worth worrying about.

So, it’s pretty common to hear about how healthy a dog or cat’s coat looks, but how much does that actually reflect their overall health?

You don’t want to be too focused on the coat. An animal can have a beautiful coat and be unhealthy and vice versa, just like a person. Having said that, there are certain diseases with which the coat can be an early warning sign. This can be anything from the texture or density of the fur to actual hair loss. As I always say, we’re dealing with patients who are nonverbal, so looking at the coat can be another tool that enables us to understand what’s going on with our pets. Plus, the coat covers the skin, which is the largest organ in the body. It’s not going to tell you exactly what’s going on with the skin, but any clue can help. We’re dealing with patients who are nonverbal, so looking at the coat can be another tool that enables us to understand what’s going on with our pets.

Regarding the skin, are there skin diseases that dogs and cats specifically suffer from?
There are a lot of diseases that can manifest themselves in a pet’s skin, but some of the most common types are hormonal diseases, like hypothyroid, and Cushing disease. Hormonal diseases often manifest in the skin, the coat, or both. The other major category is immune-mediated diseases like various allergies, lupus, pemphigus, and vasculitis, to name a few. Doing a thorough skin examination is a really important part of the annual physical exam — you have to look at these little clues and really be a detective because your patients don’t speak. With many of these diseases, like diabetes, there are plenty of other symptoms besides skin-related symptoms, but the skin can be a very useful indicator. By the time the pet parents realize something is wrong and the animal is drinking tons of water and peeing uncontrollably, the diabetes might be pretty far advanced. On the other hand, if we see certain changes in the skin and the skin texture during the pet’s annual exam, we could potentially catch that a lot earlier.

Interesting. I’m going to skip ahead because that makes me wonder about scratching, which I would imagine is another tell. It’s normal for our pets to scratch. They do it all the time and it’s kind of part of how they clean themselves. But when should you be worried? When is it too much?

We all scratch here and there and definitely dogs and cats do. What I tell clients is to pay attention to what is in your mind the baseline of your dog or cat’s scratching. If you’re seeing a trend where it’s becoming more and more intense and suddenly you’re more aware of it, you should absolutely make a note of that. There’s great variability in the amount of what’s normal for your pet. And again, it’s not necessarily easy to know how much an animal is scratching. I always go back to what my old dermatology professor Denny Scott would say. He said that dogs scratch and the whole world knows that they’re scratching, but with cats, nobody knows. He referred to them as “closet scratchers”. They’re very quiet and very stealthy about it because they’re cats. So you have to be more observant, but either way, it is still possible to notice an abnormal amount of scratching. Basically, if all of a sudden you’re noticing how much your pet has been scratching, that’s something worth checking out in and of itself.

Maybe this will have the same answer, but what about sneezing? Animals sneeze the same way we do, it seems like, but do they do it for the same reasons? Like, when there’s something irritating in the air or something irritating in their respiratory tract? Do they have respiratory allergies like we do?

When you and I sneeze it’s typically because there’s inflammation in our upper airways. The cause of it can be a lot of things — viruses, bacterial infection, allergies, and so on — but they all trigger inflammation in our upper airways and, as a result, we sneeze. For the most part, sneezing can be similarly related to inflammation caused by either allergies, infections, and in rare cases parasites. With parasitic or microbial infection, you want to treat that and get rid of the infection. With allergy-related sneezing, it’s about quality of life. If your pet is constantly sneezing, maybe that’s going to affect their quality of life. But if not, why worry? A good example of this is how I handle the very small number of cats that I’m allergic to.

Really? Even after working so long as a veterinarian, you’re allergic to cats?

Not all cats and not any specific breed, but there are certain cats that just get to me. I think it’s something about the specific proteins in that cat’s dandruff or something. However, it doesn’t happen very often. Even when I was seeing patients every day all day, it would only be once every couple of weeks that a cat would get to me and I would start sneezing. Now, I’m not going to take an antihistamine every day just because every couple of weeks I have to sneeze my way through an appointment. Similarly, there are a lot of annoying but inconsequential things that can cause sneezing in pets. Unless it’s a danger to their health, I usually recommend that pet parents just ignore it. If your pet is constantly sneezing, maybe that’s going to affect their quality of life. But if not, why worry?

Sometimes the best thing you can do is nothing, after all. Anyway, that segues nicely into my other question: What things are animals allergic to? What are their environmental triggers?

So this will be an oversimplification if we have any veterinarians reading, but I think this is the easiest way to explain it. Basically, I group pet allergies into three buckets. There’s environmental exposure, there’s food, and then there are parasites — fleas, lice, etc. Those are pretty straightforward: just deal with the parasite to relieve the allergy.

Makes sense.

The next one, food allergies, is not the most common of the three. There are definitely pets that are allergic to food, typically a source of protein or carbohydrates. It typically has nothing to do with the quality of the food. You could feed them better food than you eat, it’s just that their immune system overreacts to certain proteins or carbohydrates and goes into overdrive. My old Jack Russell had an allergy like that, and we had to feed him hypoallergenic food.

The last type of allergic reaction is environmental, and it’s the most common. There are two ways pets can be exposed to allergens in the environment: breathing them in and coming into physical contact with them. Just like with food allergies, the pet’s immune system overreacts and goes into overdrive.

What are some options to treat these allergies?

For food allergies, the only thing you can do is an elimination diet to try to identify the specific food that the pet is allergic to, but that’s often a big commitment. Everyone in the household has to be very strict about feeding the dog only hypoallergenic prescription food for the entire elimination period, which can take three months. No treats, no pizza crusts, no little bits of chicken under the table, nothing. For environmental allergies, there are now a few options. These include anything from a combination of steroids and antihistamines to immunotherapy like Cytopoint injections to other therapeutic modalities. Now, all of these medications don’t cure allergies. You can put a dog or a cat on steroids and they’ll stop itching, their skin will look beautiful, and everybody will be happy. However, if you stop the medication, the symptoms will come back. They don’t cure the pet of its allergy but they do relieve the symptoms. If the medications are working and the pet is comfortable, that’s great. I have a dog that has severe, chronic allergies, and I’m able to manage it very effectively with two different types of medication. But if you really want to try to treat the allergy itself, there is also the option of desensitization allergy injections.

I think I’ve heard of this. Is it basically like exposure therapy, where you inject small amounts of the allergen into the animal to help it develop a tolerance?

Yes, exactly. You’re desensitizing the immune system to stimuli in the environment. I say allergy shot, but it also comes as a sublingual oral medication now. Either way, it can be very effective, and it’s the only modality that can actually desensitize an individual to allergies and actually cure those allergies. But it doesn’t work 100% of the time. In my experience — and there’s different data on it out there — it tends to work beautifully 25% of the time. Another 25% of the time it’s a total failure and then there’s 50% in the middle where it works but not completely. Depending on the allergy and the seasonality of it, the injection can be more or less effective. This just means you might have to do a little bit more in peak allergy season, like adding medication. My own dog, Poco, the one with severe allergies, is on allergy shots that he gets once a month. But especially during the spring and summertime, I give him other medication to help with symptoms. The other thing with allergy shots is that you need to know exactly what your pet is allergic to. You need to do some testing to know, “Is it pollen, is it mold, is it dust?” Then you can develop a specific injection to desensitize them to that.

What kind of things is Poco allergic to, if you don’t mind me asking? Is it seasonal pollen?

Well, there is pollen that I think makes it worse in certain seasons, but he’s allergic to dust mites, which are present year-round. He’s allergic to certain grasses that are always around. That said, there’s definitely seasonality as far as the intensity of it. But that’s him. Another dog could have a very different profile of what they’re allergic to.

So different pets will all have a different reaction to different allergens? I guess that tracks, given how allergies express themselves in humans.

Yes, which is why there’s not a one-size-fits-all treatment for allergies in animals. So many things can affect it, including even what region you live in. If your pet is allergic to, say, cedar pollen, and you live in Arizona, you’re not going to have any issues. But if you live in the Pacific Northwest? That’s another story.

Okay, so that makes me wonder about mange, as you mentioned before the interview it’s not such a big deal in our area. Why is that?

It’s not common but I have seen it over the years. The thing is, it’s much more common in dogs that live in rural areas and have lots of exposure to wildlife. To be specific, I’m talking about scabies, which is also called sarcoptic mange. But it’s been decades since I’ve seen a case of sarcoptic mange here in Seattle. Even then, it was typically either hunting dogs or dogs that are not on any monthly preventative anti-parasite medications or dogs whose pet parents have a vacation home in a very rural area. It’s not very common at all. Most of the time it’s pretty straightforward to diagnose, but, again, it’s just not very common here. People also frequently confuse sarcoptic mange with demodex, which is way more common, especially in very young dogs and certain breeds of dog like pitbulls. Demodex mites are different from scabies in some key ways; they’re not under the outer layer of skin, but instead are inside the hair follicles. With both infestations, there are effective ways to treat it.

Scabies can transfer from pets to people though, right?

Yes, but most other insect or mite infestations can’t. Demodex mites can’t, lice can’t. If your kids have lice, they didn’t get it from your dog. Sarcoptic mange is really the only one that you need to worry about besides maybe some sort of fungal infection. But you really don’t need to worry about scabies too much here.

Our pets aren’t getting mange from running around in the city parks, basically?

I’m sure somebody’s dog somewhere got it locally. And it also jumps from one dog to another, which is another vector. So of course it’s possible, but overall, if you talk to veterinarians in our area, it’s extremely rare.

That’s good! That’s very comforting.

Funny story — I think I told you that I moved here from upstate New York, yes?

You did.

One of the board questions to get your vet license is about salmon poisoning. It’s a classic northwest issue that pets can get from eating raw salmon. Technically, it’s not poisoning, it’s actually a parasite. It can cause severe, severe GI problems and even death. Anyway, when I moved I was sure that I was going to see a case of salmon poisoning every day in the clinic, because I just moved to the capital of salmon here in the land of salmon. I can tell you that over the years here in Seattle, I’ve seen maybe ten cases. It only occurs in certain drainage areas of the Columbia. I have diagnosed a few salmon poisoning cases over the years, but it’s extremely rare in our area. Maybe it’s more of a risk for people who live on the beach by the Columbia whose dog is running around and eating raw salmon during the spawning season. But not for us here in Seattle.

I’m laughing because we just fed my dad’s dog a bunch of salmon skin, but it was cooked and I’m pretty sure it was from a farm, not the Columbia.

If it’s cooked, you don’t have to worry about it. Even if it’s raw salmon from the Columbia, it has to come from certain drainage places. It’s not in the whole river. Anyway, I was super excited when I moved here to start diagnosing all these cases of salmon poisoning and then all my colleagues were like, “Yeah, sorry, this actually doesn’t happen.” I was super excited when I moved here to start diagnosing all these cases of salmon poisoning and then all my colleagues were like, “Yeah, sorry, this actually doesn’t happen."

It was overhyped! A couple of practical questions before we hop off. What are the best ways to prevent allergy issues with your dog or cat?

Well, I mentioned using preventative medications for parasites. That can help with a lot of issues: fleas, ticks, heartworm, demodex mites, and even mange, in the rare instance they encounter it. As far as preventing food allergies, we don’t start our life as humans saying “Oh, we may have food allergy or food intolerance and so we shouldn’t eat this, we shouldn’t eat that.” We discover food allergies when we have issues eating certain foods. If it’s not broken — if your pet is doing well on a normal diet — let’s not fix it. We’ve talked before about how to find an optimal diet for your pet, I believe in our chat with Dr. Katy from Mud Bay, and I think we talked about how I’m a big believer in the importance of rotating diets and not just feeding one diet forever. This exposes the immune system to lots of different types of foods, which in theory might lower the risk of developing food allergies and food intolerance.

And for environmental allergies?

Well, it helps to know what’s causing them. Sometimes it’s obvious, like if you take your dog to the off-leash area and there is a certain grass there and they come back with a bad rash. Same thing if you took your dog hiking and went through a grassy field and they came back and like clockwork, they have a skin reaction to that. In those cases, you can just avoid the irritant in the future. Leash them and keep them on the trail when you go through the grass. Sometimes there is stuff they’re reacting to that you can’t do much about. Like something textile, something in the carpets or fabrics around your home. These can theoretically be potential allergens, but they are not as common as pollens and grasses. Besides using avoidance when you know what the allergen is though, there’s not a lot you can do. I’d say washing your pet on a regular basis is important and can help.

Oh, this is a great time to ask my big burning question: How often do you need to wash your pets?

Hmm. On a regular basis, I’d say you need to wash a dog once a month using shampoo. That’s my rule. Are there exceptions? Sure there are. And with dogs that maybe have allergies or you suspect have an allergy to something they’re encountering in the environment, you have to do it more often and maybe you have to use a special kind of shampoo. But for normal dogs, shampooing once a month is great. All that said, rinsing them off with just water can be done much more often, especially with dogs that love swimming.

Kind of like, hose them down in the driveway when you get home?

Yeah. Or at least rinse their paws and dry them out really well. Especially if your dog is licking the paws a lot, and maybe it has some contact dermatitis and allergies, you can try to do that as a first step.

Last question. How often should you wash a cat?

Hopefully never. I never washed my cats. I mean, obviously, if they get into something or something happens it might be necessary, but most of the time it’s pretty miserable for both the cats and the pet parents. In general, though, cats don’t really need to be washed. They’re clean animals.

Having washed a cat before, I was going to ask if you had any tips to make it easier, but it sounds like your biggest tip is, “Don’t do it.”

That is the best tip I can offer. Even cats that go outdoors don’t need to be washed. They keep themselves clean. They’re a self-cleaning animal.

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