The Itchy Dog: Is It an Allergy?

Scratching is a very common symptom in dogs, and you as an owner should aim to nip it in the bud early before self trauma causes secondary injuries to your dog. However, before wondering whether your dog could have an allergy, you must rule out the common parasitic (fleas and mites), bacterial (hot spots) and fungal (ringworm and yeast) infections. See my article Is your Dog Scratching to explore these in greater detail.

Just as allergies have become more common in children these days compared to several generations ago, veterinarians are seeing far more allergies in pets too. It is difficult to explain this phenomenon, theories range from alterations in the content of pet foods to the use of modern day household cleaning products or simply genetic evolution. One thing is certain, whatever the cause, allergic dogs benefit hugely from avoiding the offending allergen or, if that is impossible, appropriate treatment to minimize the itchiness.

Lets start with the presenting signs of an allergy in dogs. Itchiness can manifest itself not only as obvious scratching at the neck and flanks, but also as face rubbing, foot licking or chewing and over grooming. Foot licking, for example, is often perceived by owners as normal, when in fact the dog is responding to itchy feet in the only way it can, by licking them. The skin between the toes may turn red and sore due to the compulsive licking, and in white dogs such as West Highland White Terriers and Bichon Frises, the fur is stained brown by saliva.

Ear infections are another common sign of an underlying allergy. Though general waxiness, hair in the ear canals, lack of ventilation, bacteria and yeast may trigger the infection, an underlying allergy is often the root cause of the itchiness. If your dog gets recurrent ear infections, by eliminating an underlying allergy you may prevent your dog from going over the itchiness threshold and developing full blown ear infections.

So, what are the common allergies in dogs?

For convenience they are best separated into 4 categories.

1)Flea bite hypersensitivity
2)Adverse food reaction
3)Atopic dermatitis
4)Contact dermatitis

Flea bite hypersensitivity is relatively straight forward to cure. It is a simple case of eliminating every single flea on the dog and, crucially, in his/her environment. The itchiness is caused by an allergic reaction to the flea saliva, and so even a solitary flea can trigger a scratching frenzy. To rule out flea bite hypersensitivity, all animals in the house (dogs and cats) should be treated with a reputable veterinary spot on medication monthly without fail, and the house should be thoroughly sprayed with an insecticidal spray.

Adverse food reactions are more difficult to treat as it can be difficult to isolate the precise ingredient responsible for causing itchiness in your dog. Not only that, treating adverse food reactions requires owners to be exceptionally disciplined and motivated in preventing their pet having even a single treat unless the exact ingredients are known to be safe.

There are two ways of diagnosing an adverse food reaction (also known as a food allergy). For those readers for whom cost is not an issue, a blood test can be done to measure for ingredient specific antibodies in the bloodstream. The blood test is quite costly, and if combined with a blood test for environmental allergens is usually upwards of $400 (£200). The company performing the blood test then provides a list of ingredients (chicken, beef, pork, rice, wheat etc) and a score next to them, suggesting which ingredients are best avoided. The owner then picks a commercial diet which does not include any of these ingredients, or indeed a special home cooked diet. The second way to diagnose an adverse food reaction is to conduct a dietary trial. This involves picking a very bland hypoallergenic diet and feeding your dog exclusively that for at least a month, preferably 6 weeks. The author usually suggests turkey and rice, as less dogs are allergic to turkey than chicken. Of course if your dog happened to be allergic to rice or turkey, which is rare but nevertheless possible, you would be none the wiser as the itchiness would continue and you would assume you had ruled out a food allergy having done the turkey and rice dietary trial. Remember if you are doing one of these trials, then your dog must not be given any treats, especially not pigs ears, chews, boneos, dental sticks or any rawhide products. Literally nothing must be swallowed other than turkey and rice (and water!) for the entire trial period.

If you have ruled out flea bite hypersensitivity and ruled out an adverse food reaction, the next step is to consider an environmental allergy, also known as atopic dermatitis. Symptoms of atopic dermatitis usually begin between 1 and 3 years of age, though any age is possible. The itchiness is often seasonal, which is consistent with a pollen allergy, though some dogs are itchy all year round. There are certain breeds which are predisposed to this condition: Boxers, Bull Terriers, Dalmations, English Bulldogs, German Shepherd Dogs, Golden Retrievers, Labrador Retrievers, Shar Peis, Shih Tzus and West Highland White Terriers being the most commonly affected. Diagnosis is usually made based on the history and ruling out all the other causes of itchiness, and many vets will treat the condition on these presumptions. However, definitive diagnosis can be achieved via a panel of injections into a patch of skin, or blood tests. Neither of these are particularly effective and generally not performed unless the owner is prepared to attempt a desensitization programme. This involves a long term course of injections given by your vet on, say, a monthly basis to desensitize your dog to the offending allergen, and so make the allergic reaction much smaller when he/she does come into contact with it.

Contact dermatitis is a skin reaction caused by your dog coming into contact with a chemical that is an irritant. It therefore only tends to affect the stomach, groin and feet of the dog, and is characterized by reddening and drying of the skin in these areas. It can also be seen when owners shampoo their dogs with a product that is not intended for use in dogs. Contact dermatitis is rare, but easily ruled out by careful use of cleaning products around the household. Just think, did the itchiness coincide with the introduction of a new carpet cleaner, washing powder or fabric softener?

By far the best treatment for any allergy is avoidance of the cause. By careful investigation and following the steps above this is often possible, especially for flea bite hypersensitivity, adverse food reactions and contact dermatitis. If avoidance is impossible though, as is the case for many cases of atopic dermatitis, then seasonal or lifelong treatment may be indicated. Steroids are very effective at stopping itchiness caused by allergies, but long term use can lead to undesirable side effects, such as adrenal gland disease. Long term steroid use should only be used as a last resort, when other medications have been tried and failed. These other medications include antihistamines, essential fatty acids and medicated shampoos.

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  • florayg

    Can anyone advise on a horse itchy allergy?
    In the summer for the last 3 years my 18 year old horse has had bouts of intense itching on her back which cause her to rub herself raw and bleeding over spine and ribs unless I keep her in an electric pen. The bouts come and go with no pattern. It makes no difference whether or not I ride her, although sometimes she is so itchy I can't. It's NOT sweet itch as she already has this and it is well controlled with a Boett rug, but the rug has no effect on the back itching. Has anyone else any experience of anything like this? Any helpful ideas? My vet has none. She has this sometimes in winter also, but less often.
    She's had loads of tests and has multiple allergies to various pollens and foods, but the vet has never seen this type of reaction before. I've checked out all the washing powder, soap, fly repellent possibilities
    I've hed healers, homoeopaths and herbs to no effect. If I don't ride her for weeks she still has it so its not due to being ridden. Help!

  • Emmarose

    I would not be happy at my vet fobbing me off. You should insist on having a skin sample analysed to get to the bottom of your horses problem. Good luck
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  • Cruz

    call your vet, it could be a allergic reaction to something in her environment she may need antihistamines to control the itching.

    Give her a nice bath using diluted hibiscrub this also may help her.

    best of luck.
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  • superchipbigal

    Try using flea and tick powder.This cured my mare of virtually identical symptoms last year.Please don't dismiss this advice because it is cheap and simple.It really could be most effective.
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  • Exquisite One

    My mare has sweet itch and will not stay in a fly sheet. So, I give her 2 gms of dexametasone a day to control the itch from the end of April until mid October. I also try to keep her in her stall during the dawn/dusk and night hours with a fan on and a lot of bug spray.

    Dexametasone is a steroid and needs to be used judiciously. Prednisone can be used -and is cheaper – but caused horrific temperament changes in my mare- who is 6 yr. old Trakehner, by the way. I also use a topical cortisone cream on my horse if she gets a bad bite. She will get hives and scratch herself bloody and raw. On the Dex, she seems a little calmer and holds her weight better. (She is a hard keeper/high energy/high spirited horse.) I have been having to do this since her 2 yr. old year. If I wait too late in the spring to start giving it to her, I have to give her like 8 grams a day for a week and slip back. This is a fairly low dose for a 17hh 1378 pound horse. I hate that the cortisteroids can affect the immune system – but this is already an immune system problem. So…….which is better – a miserable – immune compromised horse -or a comfortable immune – compromised horse? I have opted for the comfortable horse. I suspect your horse, like my horse, is thin skinned and has to be groomed gently. I wash her twice weekly with Eqyss shampoo and use Eqyss conditioner and a tea tree oil for itchy spots. She is very sensitive to shampoos, conditioners, etc. So, I use the most natural products that are supposed to help with the itch.

    Since this is coming on her back and withers, if you are using a wool fleece pad – it is possible she is allergic to the lanolin in the wool. Or even the material your saddle pad is made of – or what you are washing it with. Or, perhaps the saddle cleaner you use. ????

    I wash my horse stuff in baby DREFT soap and let it air dry. Try buying just a cotton pad and keeping it very clean.

    It might also be possible that the boett is no longer working, as they can still get bitten under the jaw area and nose. Try covering that area in Crisco vegetable grease or a grease based fly repellant.

    An allergy is just an immune reaction to something you've been exposed to. It can take one time exposure or multiple/years of exposure to develop an allergy. My Mom and 1 of my brothers are allergic to bee stings now – but neither were when they were younger – my Mom was about 60 when her allergy developed and my brother was about 30. Both had been stung previously more than once. So, it could be a pollen or bug or feed additive or whatever – and now it's a problem. Most likely, you can't prevent exposure to the allergen, only treat the symptoms of the allergy. I hate it, too! But maybe some day we will have a better treatment.

    P.S. I take Dexametasone in the winter myself for eczema. It doesn't cause me any emotional or physical distress – and I had to take prednisone once and thought my head was going to explode. I hope that makes you feel better.

    There are lots of allergy treatments and shots, but my equine vet said that they don't work, and are very expensive.
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  • ann113599

    There is a wash you can get from the vet we have to use it on one of our horses as he does the same as your itches until he bleeds, he has a fly rug mask etc but we have to wash him in this shampoo once a week and i must say this year he is not only looking better but he does not seem to be itching so much either.
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  • SUZANNE R

    It sounds like an allergy to something-check her pasture as it could also be overheating of the blood due to rich grass-doesnt sound like bites as you say she doesnt get them in a pen.!!xx
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  • qtonsonnydundee

    i would start by testing her for allergies, because i know of a horse that had a very similar case and it turned out that he was allergic to hay, dust, pollen, etc. and once they got his allergies under controll he stopped itching
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  • jamla

    i had similar prob with mine. after lots of tests by my vet's they where unable to come up with what it was. it normally happened in end Aug / sep. like yours but yellow puss coming out of pin pick holes . we thought it was a acid attack by some one.vet did no end of tests blanked. i found that as soon as i saw a very small area missing / going bald , i would wash it well / scrub with normal sort of anti -bacterial shampoo , dry it well the apply the human "sudocream" stays on in wet weather and it stopped it getting any worse. but you may have to wash every 1-2 days. this worked for me but must catch it while the sore is small. good luck
    p.s a friends horses was allergic to grass and got these sore's all other her body if tuned out, cound'nt have hay either ! you have to try out diff things to rule out things
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  • Kellllyyyy

    She might be allergic to noseums which are very small insects.
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    I have 2 horses with that problem.

  • Ladyfromdrum

    This is a long shot, but I used to have a horse who was allergic to biological washing powder and I had to wash his numnahs and rugs in the sort of detergent you would use on baby clothes such as Persil Baby non-bio.
    I know it is hard to believe, but they actually have very sensitive skin.
    Could she be allergic to the fly repellent you are using?
    Has your vet taken a skin scraping?
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  • cowgirl3175

    silly answer, but maybe, is your horse light colored? maybe sunburn? just a suggestion.
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  • Single4Good

    Assuming your term "sweet itch" means allergy to no-see-ums (Culicoides) well I have them bad at my place and some of the allergic horses will scratch their backs also.

    You mention it seems to be seasonal but did not say what state you live in – do you get extended bouts of cold or are you warm thru the winter? In FL those darned gnats can be active thru much of the winter though much less than summertime.

    If the problem is only in the saddle area I'd say there is a problem with either the pad material or sweating under the pad. Make sure you thoroughly rinse her back off after riding. Also scraping the area when it is bad and having a culture done may help.
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  • Zeb G

    Find a Kanisiologist. I don't know where you live but you may be able to get on line and do a search. This alterative threapy is the most amazing thing to see. My own horse is being treated for sarcoids at the moment and they are going. He has had them for 5 years. (He is 8) He also had (please note the HAD) stable allergies. She sorted those out to.
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    Zeb Graham-Howard Equine Reiki master Teacher/Practitioner & EquineTherapist.

  • txpainthorse

    My horse has allergies and they took a skin sample and sent it off the Texas A & M to find out specifically what the problem was.
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  • Madeleine K

    it could be something like hives, fleas , or ticks!!!!!!!!
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  • david_manger2000

    hi ,try chalk or,(talcomb powder) and put on a light fly sheet
    References :
    the animal whisperer

  • Rachel

    Use Aloe Vera its great you can feed it and use it topically straight to the effected area, it is a natural steroid so really helps.

    My horse suffers from allergic reactions, to insect bites and it has been great for her.

    I went through all the skin test etc etc and this is all the dermatologist could suggest.

    The best thing is its all natural, not harmful and competition legal
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