Got an itchy pet? Losing hair? Diagnosed with “allergies” or “allergic skin disease”? Are the summer months causing your pet especial distress? Then you’ve likely been offered “allergy testing.” But what, exactly, does that mean?
For starters, it means we rule out all other potential causes of skin disease to make sure we’re not all hung up on the allergy thing for no good reason. This includes serial skin scrapes to look for bugs, superficial skin cell testing (cytology, usually via “impression smears”), ear swabbing for cytologic (cell) evaluation and cultures and blood testing––typically for hormonal diseases (like Cushings or thyroid disease). For some kinds of lesions, skin biopsies are sometimes in order as well.
Then we go for basic palliative care to see what tends to work. What’s the response to shampoos, dietary supplements judiciously chosen drugs (like antihistamines, steroids, flea meds, other insecticides, cyclosporine, antibiotics, antifungals, local treatments, etc.)?
So you know, this isn’t necesarily done just to take the easy way out. Response to treatment can be a significant indicator of what’s up with the skin. It can also power you through the short seasonality of your pet’s problem––if, indeed, it’s seasonal.
Next up, we’ll try food trials to determine whether one or more proteins and/or carbohydrates are stimulating the immune system at the level of the skin. Here’s a complete post on this.
Once all this has been accomplished, we may recommend you see a dermatologist for allergy testing. Sometimes we’ll recommend a dermatologist even before all this intensive testing. For my part, I tend to refer to a dermatologist when the problem is severe and/or intractable and if I’m uncomfortable with or confused by the test results or a pet’s clinical response to treatment (which happens with occasional regularity).
At this point, we can elect to go one of two ways: Depending on your pet’s response to treatment and your comfort level with drug therapy (and its expense) we can either choose to stick to what we know already works or we can move on further testing.
Here’s where things can get tricky. It’s ime to bring out the big diagnostic guns: skin testing and/or blood testing to determine which specific allergens are causing the problem. This is most helpful for inhalant allergies (also referred to as “environmental” allergies, “seasonal” allergies or “atopy”). Food allergens may be tested, too, but these tests are very insensitive and non-specific relative to inhalant allergen testing.
In fact, recent studies show that food allergy testing through skin or blood can be downright wrong (and, frankly, inadvisable), which is why we like to stick to well-run food trials for food allergies.
Some vets use skin testing (dematologists, usually, since these are expensive to maintain in house) some use blood testing (as I do when I haven’t referred to a dermatologist) and some use both, knowing that both tests have their limitations.
If you’re like most of my clients, you’ll think it a bit above-and-beyond-ish to test your pet for allergies in the way we do for humans. It’s expensive to have skin tests performed. It’s also pricey (though usually less so) to go for its alternative: blood testing.
Skin testing: $500 to $1500, depending on the number of allergens tested and the priciness of the hospital. Blood testing (or “serology”): $100 to $800, depending on the same above factors.
Nonetheless, a pet’s allergic skin disease is often severe enough to warrant these advanced tests. (I perform about one to three every month).
Problem is, pricey as they are, they’re not perfect. Though they grant you a formidable glimpse into the categories of allergens that are most responsible for a pet’s individual allergic profile, they’re “off” in many cases. Here are some limitations:
For both kinds of skin testing, pets must be off all immune system-affecting drugs for six weeks. That means no steroids, cyclosporine or antihistamines (though antihistamines may be continued up until one week before testing). No changes must be made in the animal’s basic routine (feeding, environmental exposures, etc.)
Moreover, even when we think everything’s well controlled in the pet’s environment (same food, same shampoos, same everything), pets can have different immune responses to allergens on different days or different times of the year. Stress can interfere with responses, too.
For skin testing, veterinarians clip the fur, inject a small amount of each of up to 50 allergens into the skin and record the size of the swelling (indicating the immune response).
The problem is that different vets will have different ideas as to what constitutes a high or low degree of skin response. Human error and inconsistency, even on the same patient, is always a factor.
For blood testing, the issue is that different labs will come up with different results. Blood handling, human error, allergen purity, etc. can all interfere. For that reason, dermatologists often claim these tests are poor substitutes for skin tests. The skin test is the “gold standard” because it’s carefully controlled by a specialist.
And I would tend to agree. Nonetheless, I’ve had great results on the many blood-based allergy tests I’ve performed. My local dermatologist, Dr. Millie Rosales, concedes that she sometimes uses serlologic testing, too, and that certain labs seem to produce excellent results––results comparable to skin testing. Still, all allergy tests––skin or blood-based––need to be taken with a hefty grain of salt.
So why go through with it at all? What does it help to know what you pet is allergic to? For two reasons:
Because knowing what’s causing the problem can help you avoid some of them. Sure, you won’t be able to avoid pollens, but wool, jute, cotton and fleas? Your knowledge of their allergenicity can make a huge difference to how carefully you approach these substances. Because we can always formulate a custom-made vaccine against the allergens your pet can’t avoid (molds, trees and grasses, for example), this is an excellent option––if you’re willing to assume the additional expense and the work required by regular allergy shot administration.
It may sound like a lot of work, these allergy shots. But they’re really not. Subcutaneous injection is easy in pets. We can teach you how to have it done. And we’re always happy to do them for you if you’re willing to come in on a regular basis (frequently at first then only once a month).
The best part about an allergy vaccine protocol is that no drugs are administered (though many pets may need drugs to remain comfortable until the vaccines kick in). These are natural substances that work because the gradually increased levels of allergens in the shots are helping the body’s immune system become acclimated to them––instead of producing the aberrant immune response responsible for the allergies.
The trouble with this approach is four-fold:
1-Pets can over-react to the increased levels of allergen, resulting in more itching, redness or even anaphylaxis (though this latter issue is rare). In these cases we back down on the rate of allergen increases.
2-Pets can develop allergies to new substances over time, requiring that we re-submit blood samples or re-do skin tests periodically (often every 12 months or so, though some pets may never need a re-test and may even have their vaccines successfully discontinued over time).
3-Some pets (about 40%, it’s estimated, may not respond well enough to allergy shots to warrant the work and expense (about $100 to $500 every 9 months or so).
4-As mentioned before, tests may not provide accurate results––which may account for vaccine failure as discussed in #3.
***
That’s it for now. Phew! Have anything to add or ask? I’ll take it all up, but give me a few hours to respond, I’m wiped out for the moment.
Add Comment21 Comments
Thanks -- this was very timely. I have two cats with seasonal allergies, which have been well-controlled with antihistamines for the past 7 years; but this year they've been worse than any time since we started treating them, and I've been wondering about options, so thanks for giving me things to think about. Incidentally, I gave them Frontline in case fleas were the cause of the extra itching, even though I hadn't seen any fleas, and one of the cats lost a patch of hair where I applied the Frontline and his skin became scaly and flaky. Is this a common reaction to that product?
T.T. June 30th, 2009 02:40:47 PM
I'd be interested in knowing what laboratories are most trusted for some of the testing.
We have some strange results being given around these parts stating that some cats and dogs are allergic to ALL animal proteins.
When it comes to specialized diets with a variety of options such as fish, venison, potatos..etc., it seems a bit suspicious.
So when you recover maybe you can tackle the favorite labs because naming those questionable ones will certainly be controversial...
LOL
;-)
Ark Lady June 30th, 2009 04:27:39 PM
"For both kinds of skin testing, pets must be off all immune system-affecting drugs for six weeks."
Do you mean both types of testing (blood and skin)?
As far as blood tests for food allergies go, I know that they're notorious for false positives, but are negative results considered reliable? In other words, might they be useful for a severely allergic dog to determine which foods might be OK to use in an elimination diet (particularly if the dog's dietary history is unknown), or would be OK to use in a limited diet to get allergies under control?
Mary Straus June 30th, 2009 07:16:28 PM
I'm also curious to know about the blood tests for food allergies. My dog's blood test came up showing that she's allergic to lamb and eggs, as well as about a million environmental things (including human dander- that one made me cry). I had already figured out that she was allergic to lamb through food trials, but I hadn't figured out the egg piece.
Also, I'm curious about the typical ages a pet might start showing allergy symptoms. My dog started showing symptoms at about 6-8 months (she chewed the fur off her paws/lower legs, and then started removing the skin), but my vet was hesitant to test her because he felt it was unlikely that a dog so young could have allergies.
Finally, are allergies genetic? My dog is a puppy mill rescue; I've often wondered if her allergies are simply due to bad breeding, a bad environment or both.
Crystal June 30th, 2009 08:04:43 PM
Dr. K - I am also curious about the blood tests for food allergies - you mentioned recent studies showing their lack of reliability... do you mind providing a link to these studies?
I ask because it's been my opinion for MANY years that these tests are consistently wrong... proved by dogs who have tested allergic to certain food items and subsequently have eaten them with no reaction.
When people come to me with food allergy tests and I am trying to persuade them to perform elimination trials, regardless of what the blood work says, they hold fast to the promise from their pet's veterinarian that the results are in fact accurate. Of course, they generally take the advice of their vet or specialist over mine (and rightly so!!) but if I could provide them with a study showing the potential shortfalls.
Kim June 30th, 2009 08:43:07 PM
I have a cat that is about 12 years old. When I was in school and she was approximately 2 years old I had her skin tested at the school for allergies. She had some VERY bad chin acne/lesions that we were even worried they were cancer they looked so bad. She 'reacted' beautifully to the intradermal test and has been on allergen injections ever since. She still has times of the year where she has flare ups because of outside things and god lover her she is most allergic to house dust mites. I have been trying to get rid of my carpet for years.....no money to do so....but when that happens I envision her even having less flare ups. Overall her control has been excellent and I have been able to stay away from steroids. I have found that the thing that is also helping alot is giving her an oral fatty acid supplement....I use the 3V caps and I can totally tell a difference from when she is on them to if she is not.
J.C. July 1st, 2009 12:02:24 AM
Dr. K, what you describe seems to be the SOP and I think that's VERY sad. I made it up to the food trials, z/d, nearly constant running back and forth for vet visits, and a dermatologist wanting to throw 5 drugs at my dog simultaneously before I put a halt to it all and did a bunch of research. I have to disagree with the SOP at least to the extent that there's a big step left out at the very beginning and that's to take the dog back to very basics. Good food, good water, good bathing products; ditch all the unnecessary crud the dog is being exposed to. See if that alone gets improvement without the stress of recurring vet visits (at least we find vet visits stressful, time consuming, and exhausting). Much of that crud will start to sneak back in but paying attention will help identify many of the offending allergens at that point. With the exception of SOME improvement from z/d, my Shiba got so much worse while under vet care mostly because it was taking forever for them to work through this process that she was hairless, raccoon faced, welted, and covered in secondary skin infections.
I didn't want to "cook" for my dogs but the improvement was so dramatic and fast I can no longer find excuses not to do it. When the costs and time for vets, meds, etc. (not to mention a cost to her for pain and suffering), fixing their food is cheaper and more effective than anything the vets did and that's despite the fact I'm fixing food for them both. We were all the way up to the food trials before a vet mentioned it "might" be their food. "Their food? So basic. And why wasn't that first up on your list of things for me to do for her?" My gut reaction was that he wanted to charge $1,000 first. Heck, I'd probably just have paid him that for a 5 minute consult and considered it worthwhile because my girl wouldn't have suffered so for so long. In retrospect, it ticks me off because it feels like he let her suffer without good cause.
OT, I try really hard to fight back that feeling toward my vets that I just mentioned. But then yesterday I find out that the ortho vet who did my Shiba's ACL/knee surgery (and, late last year, post surgery, informs me he'll be moving his practice, new location nearby, not working out with current partners, not to worry because he's not going very far, keep an eye on his website, it'll be back up in a couple of months) took a new position in a clinic in Dallas in JANUARY. Neither he nor the vet who referred me to him had the common courtesy to notify me. Not that my Shiba's been waiting for a check up, a potential surgery to her other leg or anything! Here I've been trying to be patient, trusting that he'd just run into some hiccups getting the new place going... I finally think I really need to get my Shiba in for a check up so email the referring vet to see if he knows where the ortho vet is. I get a terse email with the ortho's new website and "he's in Dallas"; nothing more; no suggestion I bring her to him or offer for a new referral; zip, nadda, nothing. Jeez, I'm pissed off at them both right now. There have to be some decent vets in Houston but I'll be hanged if I can find them! Think I'll look in the little town I'm moving to this time. Nice thing about small towns is you can hunt people down and beat them to death and they know it; does wonders for behavior.
PJBoosinger July 1st, 2009 12:59:07 AM
Oh, and I got a response on who gave out (sold) my mailing address. It's that snot ortho vet!!!
PJBoosinger July 1st, 2009 01:01:27 AM
I'll start with Mary's comment/question and move on the the others later: Yes, Mary, this is true for skin and blood testing. Immunosuppressive medications (those that are used to treat allergies--antihistamines, steroids, cyclosporine, et al) must be discontinued because it will dampen the response of both skin and serum to allergen trials. Kinda makes sense, right? Yet it's common for veterinarians to fail in this step, thus providing false negatives. No. Both negative and positives are not necessarily 100% reliable.
Dr. Patty Khuly July 1st, 2009 08:18:52 AM
TT: I've seen that reaction with both Advantage and Frontline as well as many other topicals (Adams, Hartz, etc.). It's much more common in cats than dogs (anecdotally speaking). The only one I personally have not seen it happen with is Revolution. But it's always a risk. btw, the lesions with Frontline and Advantage are mild but I've heard horror stories about Hartz product, in particular--sloughing of the skin, blistering, etc. Again, I've only heard of them--never seen them.
Dr. Patty Khuly July 1st, 2009 08:21:59 AM
Ark Lady: Wow. Tough one. I hate to name 'em because their protocols change and labs improve and slip all the time. But here goes. I use Biomedical with good results but I'm thinking of changing over to the ones my local dermatologist believes produce more reliable results: Greer and Heska.
Dr. Patty Khuly July 1st, 2009 08:24:14 AM
Kim: Here's one from 2006 describing food allergy testing comprehensively. Sorry, but I think you have to pay to get it. It's pretty comprehensive on all modes of food allergy testing, though. May be worth it.
I also went to VIN for you and noted that the current recommendations still "discourage" food allergy testing through serology. They just don't do the problem justice--way too non-specific and insensitive.
Dr. Patty Khuly July 1st, 2009 08:39:14 AM
Thanks, Dr. Khuly!! I have no problem paying for good information. :O)
I only wish that veterinarians would follow the VIN recommendations. I don't have a single allergy client who has seen their vet and NOT either had blood testing recommended or already done it. "No, she can't have carrots, her bloodwork says so!" "Does she react when you feed her carrots?" "Don't know, we don't give her any... didn't you hear me? She's allergic!!"
<sigh>
PJBoonsinger - your story is familiar. TOO familiar. My very first response now when hearing of a pet who has a possible allergy (even a slight possibility) is to bring them down to a basic elimination diet and go from there. We choose each diet based on the pet's food history, but my current favourite is mackerel and quinoa. It's inexpensive and moderately easy. We don't supplement it, at least not at first. After about four to six weeks if it's a food allergy there's generally been a change - usually for the better, occasionally for the worse in which case we change proteins and carbs and try again.
Then we start adding. First supplements, then one food item at a time, every week or so. We start with the foods that are in the commercial diet they want to feed, if they want to feed commercial. Otherwise, we just start throwing in things that the owner eats regularly. We keep a detailed list and a VERY close eye on reactions.
If the allergies don't improve, or they seem to improve but not enough to make us happy, we then submit the dog for testing - for inhalents and contact allergies ONLY ($200-300). These tests are invaluable simply because you can't control their access to dust and pollen in the way you can control food. About 80% of my allergy dogs are cleared up during the food trials alone - even those who potentially have some slight environmental allergies usually improve enough that nothing more than an antihistamine during peak seasons is necessary. Removing the food complications seems to ease the rest of the allergies.
Kim July 1st, 2009 08:55:19 AM
Kim: I'm more conservative. I recommend adding in a new ingredient every month. Sometimes the more subtle effects take longer to develop--or they're additive when environmental allergens come to bear seasonally (should atopy be part of the picture--and it often is).
Dr. Patty Khuly July 1st, 2009 10:56:56 AM
I have a M/NBeagle mix puppy we guesstimate is between 6-12 mo. old. He was abandoned by his former owner and has joined my Beagle rescue foster program. When he came to me he was missing fur primarily on his neck, chest, and belly but seemed otherwise healthy. He doesn't have fleas. He's been on Purina ONE lamb & rice dry mixed w/ FreshPet chicken.Although he didn't have the classic pattern for sarcopitc mites (didn't seem particularly itchy and didn't have hair loss on ear margins, elbows, etc.), we immediately started him on oral ivermectin and Revolution as treatment for mange. Improvement would have confirmed that preliminary diagnosis. There was no improvement. Skin scrapings for demodecosis was neg. but since there was a low grade fungal presence, he was started on oralketaconizole for 14 days. Still no improvement; in fact the alopecia got worseand he developedpatches on his shoulders and randomly along his back. Although my vet recommended a short course of prednisone, I didn't want to go that route because he is a bit hyper and already has a tough time keeping his crate dry. Next was a skin biopsy, which sadly was inconclusive, but confirmed there was no demodecosis, ringworm, or cancer. Just to rule out any possible low grade chronic bacterial infection he went on 10 days or Clavamox. In the interrim I switched his food to Avoderm. I am seeing improvement w/hair growth on the larger areas of his shoulders andback, but his neck in particular barely has peach fuzz and the skin remains quite flushed. Antihistimines don't seem to help and he never licks or bites at his paws or scrathes. Since he is a foster dog I cannot break the bank and spend $$$ to search for the cause. I lnow this was very long, but I'm running out of things to try. Any thoughts or ideas? Do I just need to be more patient?
Karen July 1st, 2009 11:10:06 AM
Karen - my retriever had this kind of idiopathic skin disorder for many years and no specialist was ever able to figure it out (and yes, we broke the bank trying).
What ultimately worked was Instinct Turkey and Duck. Not sure why - even raw food didn't give him the same results. One of the few times that commercial has worked better for us than homemade. He was never uncomfortable, just hairless and spotty. The vet's recommendation was to just let it be - after all, it didn't bother him any. However, trying to walk him without having people point at us like we were cruel, nasty people to do whatever we were doing to make our dog look like that was.... well, uncomfortable to say the least.
We just kept trying foods until we found one that worked. Elimination diet did nothing for him, and we tried about a dozen grain free foods and *dozens* of homemade recipes before we found the key.
We also tried melatonin supplements which have worked for me in the past when dealing with alopecia... they provided some improvement but not enough. Also got some results with Zinpro zinc supplements/cookies, and with Dr. Maggie's Skin And Coat supplement. Ultimately though, the food worked best.
Dr. K - I wish I could get people to go that slowly... unfortunately, they are generally too impatient. Hence the willingness to test and accept the results. They think of it as a quick fix - in my opinion it just muddies the waters, if you know what I mean. Allergies are my arch enemy these days. Soooo many sufferers. :O( And each case is so unique.
Kim July 1st, 2009 12:26:23 PM
Dr. K. I've seen what Hartz products can do to a dog. Years ago, my mom put a Hartz flea/tick collar on the family collie. Somehow the Hartz collar worked it's way under her regular collar and got stuck there. Within a week, she had a two inch wide . . . leision I guess you would call it . . . . all the way around her neck. The hair fell out, the area was hugely swollen, raw, and bloody. Once we figured out what had happened (we initially thought something had gone badly wrong with her regular leather collar) and took the Hartz thing off, it took several months for her skin to heal fully and close to a year before the fur filled in. In good fur she had a gorgeous ruff and it was was pretty pitiful to see her with no hair there. Needless to say, Hartz was never used in the house again!
Meri July 1st, 2009 02:20:09 PM
After learning food could be the problem, I suspected beef (although I can't remember why at the moment). I put them on chicken and green beans at first and the Shiba started improving within days; by 6 weeks, my Labs ears were clearing up for the first time in years. I'm patient enough to go a month of more between trying new ingredients but that's probably very much because I lucked into fast and dramatic improvements for my Shiba. There's clearly a collective burden for multiple allergies that is more than the sum of the parts. With the beef gone, a flea bite is a very small patch now instead of a huge welt. Gotta say a beef allergy in Texas is tough to manage (not to mention it seems to be an ingredient in virtually every medication for dogs) but still well worth it.
"start throwing in things that the owner eats regularly" Made me laugh. I went the other direction. As I add stuff to their diets, I end up trying it too which has been good for my health. No beef in the house now but I still sneak out once in a while for a burger.
PJBoosinger July 2nd, 2009 03:30:57 AM
Change vet to allergist and this is pretty much true for human allergy testing as well. The history is a huge part of allergy diagnosis for any species. Of course, for some, going to the basic diet can be problematic if they are allergic to one of the basic diet ingredients. It happens.
MLOKnitting July 2nd, 2009 08:54:28 AM
One of my teachers for dermatology (and, arguably, the best veterinarian who ever lived) was Dr. Frantisek Kral. He had been the chief veterinarian for Kaiser Wilhelm's army and also the Principal of the Veterinarische Technicher Hochschule (sp?) in Brno before emigrating to Philadelphia, so he was hardly a youngster when I learned from him. Dr. Kral was a colorful gentleman with a rich accent, so many stories about him have survived. One of these describes part of the interraction with a client whose dog has an itchy skin. Kral would ask, "Does your dog eating vegetables?" If the response was positive, he would advise, "He must not eating vegetables." If the response was negative, Kral would command, "He must eating vegetables!" My colleagues and I counted this story as funny and picturesque. That is UNTIL last year when I attended a "current" CE on dietary treatment of dermatitides. From the haze of Power Point slides, I came to the realization that the main point of the whole seminar was, "Whatever the hell one is feeding now, change it to something else and see whether that helps." In other words, do what Dr. Kral, of blessed memory, did and taught 45 yeaqrs ago.
Dr. Steve Dubin July 2nd, 2009 09:59:06 AM
I am so thankful for stumbling across this blog and for the doctors and dog owners willing to take the time to write. I post our story only to help others that might have our pup's symptoms. Our Savannah had been happy and beautiful for 4 years. In April of 2008, she began swelling. Paws first and then her head--and oh how it swelled. It was bizarre...morphing on one side and then the other. Her skin turned fire engine red, first at the head and then her entire body. Her ears were so swollen that the plasma leaked through the skin. Weirdest symptom was the small sores that were all over--looked like someone took an ice pick and poked it into her skin here and there--and the sticky feeling that became of her coat...the stuff was just oozing out of her pores. Docs put her on steroids which tore up her stomach and induced blood/bile wretching, etc. We almost lost her, but somehow made it through and she immediately started healing once I put a stop to the steriods and kept her on antibiotics for 15 days. After the swelling episodes, she had major hair loss on her face. We thought she had gotten stung by something outside, although she is rarely out alone.
Not so lucky...believe it or not, same time, same week, one year later, she began the same symptoms. It was less this year, but still scary. We stayed off the steriods and hit the antibiotics and antihistamines (although I hate the antihistamines and usually discontinue earlier than they tell me to) + a peroxide based shampoo weekly. I read an article on the mite saga and her symptoms seemed to fit. Took her back to the vet to ask, but she said no and said she didn't need to do a scraping. Now they say an airborne allergen or food allergies. My yard is basically down to nothing now and for awhile, we wouldn't even let her go into our own yard for fear it was something there. Doc recommended allergy blood tests, which I finally relented to do because she was so insistent. It came back that she is allergic to almost everything--well, not everything, but tons! Lamb, Chicken, peas, all types of grass, molds, yeast (which is in just about everything), and I could go on and on. Not allergic to beef or Turkey, so they say although I don't understand the chicken-turkey non-connection?????
Long story short, she is better but not cured. Her hair loss seems to be filling in again, although not perfect. She still chews/bites her paws/legs + itchy--no fleas here. Daily we look for the ice pick type sores on her head as an indication of a reaction + look for swelling/redness. I now make her food twice daily. Right now, we are on ground turkey or high grade ground beef, mixed with baked potato, a tad bit of canola oil, light bit of salt, 1/5 of a daily vitamin, and I plan to go get some bone meal. I do have a couple of questions for the doctors:
1. Any kibble type recipes I can make that don't use rice and powdered milk?
2. What are the ice pick type sores? Should I go back and demand a skin scraping?
3. Our vets seem to have "never seen her combination of symptoms" despite being a huge well-known clinic in San Diego. Any docs or owners on this site ever seen these symptoms?
4. My vet has not recommended food trials--preferring to believe these blood tests are gold. I worry about introducing something she is allergic to and causes this major reaction again. For instance, she loves chicken. How do I reintroduce this (even though docs say NO...she's allergic (although came back low as a "1") without causing her to go into this deadly reaction?
Apologies for the length of this entry...just wanted to give those looking for answers and those looking to help a complete story.
Any ideas greatly appreciated! Kristi and Savannah :)
Kristi July 17th, 2009 10:56:00 AM
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