If your dog is scratching excessively, sneezing or has an upset stomach, it could be a sign that they are suffering with an allergy. Dogs, like humans, can develop allergies if their immune systems have a hypersensitive reaction to a foreign substance. There are three main types of allergies that affect dogs – fleas, food and environmental allergens.


A flea bite allergy is probably the most common allergy found in dogs. The majority of dogs will only experience slight skin irritation if they are bitten by a flea but some can have a severe reaction caused by an allergic response to the chemicals in flea saliva.

For dogs that are allergic to flea saliva, just one bite is enough to cause intense itching. This leads to them chewing and scratching the affected area until the skin is raw. There is a risk of secondary bacterial skin infections in cases where a dog has damaged their skin through intense scratching so they may need a course of antibiotics.

In addition to a strict regime of preventative flea control, an owner can help an allergic dog by frequently washing bedding and soft furnishings at a high temperature to help keep the home a flea-free zone.


A food allergy or hypersensitivity can develop to almost any protein or carbohydrate ingredient of pet food. The most common ingredients to cause a reaction in dogs are beef, chicken, lamb, eggs, dairy and soy. In some cases, an allergic reaction is caused by vegetable protein (such as wheat) or from additives and preservatives in processed pet food.

Signs that a dog could be suffering from a food allergy include itchy skin, stomach upsets and respiratory issues.

The most successful way to treat a food allergy is to identify what it is a dog is having a reaction to. This needs to be done by moving the dog on to a strict elimination diet. A vet will recommend feeding a hypoallergenic diet that doesn’t include any ingredients that a dog has eaten before. For this to work, nothing additional should be given to a dog (such as treats or table scraps) and owners should be vigilant for any scavenging behaviour.

Signs of allergy should improve after eight to 12 weeks, after which time other foods can be gradually reintroduced one at a time to see what triggers a reaction.


Environmental allergens such as pollens, grasses and house dust mites can all trigger reactions in dogs and while they can suffer hay fever-like symptoms it is most often their skin that is affected. Known as atopic dermatitis, an affected dog is likely to be severely itchy and may frequently rub their face, lick their feet or scratch excessively.

Most dogs with atopic dermatitis begin to show signs between one and three years of age, and some breeds of dog seem to be more prone to skin reactions than others.

If a dog’s allergy is triggered by pollens an owner might notice their symptoms being seasonal but if it is house dust mites that are causing the reaction, the symptoms are likely to be present all year round.

Environmental allergies can be tricky to deal with but possible treatments include anti-inflammatories, medicated shampoos and the injection of very small amounts of an allergen to desensitise a dog (if the specific allergen responsible can be identified).

You can help to limit the impact of environmental allergens by frequently washing your dog’s bedding at a high temperature and brushing them regularly to remove debris from their coat.

When to see your vet

If your pet is displaying any of the signs of an allergic reaction such as itchy red skin, hair loss, over-grooming, paw chewing, or sneezing, you should seek veterinary attention to try to determine the cause of the reaction.

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If you found this article interesting, why not read:

Allergy Symptoms In Cats

Flea & Tick Prevention for Your Dog

Food and Plants Dangerous to Cats and Dogs

Reading Pet Food Labels