What are allergies and what do they look like in pets?

Allergic conditions in dogs, and to a lesser degree cats, are a common problem in the warmer months in New Zealand. An allergy occurs when the animal’s immune system over-reacts to an allergen to which it is exposed. An allergen is capable of triggering an allergic response. There are a number of sources of allergens. Common allergens in New Zealand include pollen, grasses and other plants, fleas, food, and dust mites. Environmental and flea allergies are more likely to occur in the warmer months when there are more of these allergens around.


The most common manifestation of allergies in pets is itchy skin. The stomach and groin area, or the feet are most common, but itching can affect any part of the body, including the ears. Some allergies affect the respiratory system and present as coughing and sneezing, and occasionally nasal or eye discharge. Gastrointestinal issues – vomiting and diarrhoea – can also be indicators of an allergic reaction.



Types of allergies

Atopy: is a broad term referring to the tendancy to develop allergic reactions.

Signs of atopy include:

Red, itchy, inflamed skin in the groin, abdomen and armpits. In severe cases the whole body may be affected, skin infections can develop when the animal constantly licks and chews at one specific location.

Rubbing the face. The muzzle and around the eyes may be affected.

Chewing feet. The fur is often discoloured a red-brown colour.

The skin between the toes and pads may be red and inflamed and may smell.

Itchy ears. These may be red, and have a discharge and odour.


Asthma-like signs such as wheezing and respiratory problems (more common in cats).


Flea allergy dermatitis:  This condition is a hypersensitivity reaction to the various compounds in flea saliva. Some animals are very susceptible to flea allergies, while others may be non-allergic. Allergic animals may experience intense itching. Both cats and dogs may scratch or lick intensely at one or more of these spots and develop a skin infection.


Contact dermatitis : This condition occurs when an animal has an allergy to carpet, cleaning agents, plastics, or some other substance they come in to contact with. Contact dermatitis manifests as itchy red lumps in the groin, abdomen and feet. Hair loss can occur in chronic cases.


Food allergies: Many foods, or specific food ingredients, can also cause allergies. Food allergies are commonly a response to the protein component of the food, such as beef, lamb, chicken, egg, soy, wheat or corn. Food allergies can manifest as itchy skin, usually around the face and legs, and gastrointestinal issues (vomiting and diarrhoea).


Severe allergic reactions (anaphylaxis): Dogs and cats, like people, can experience severe allergic reactions. These reactions are usually in response to an insect bite or sting, contact with a particular plant, or ingesting various foods or drugs. In mild to moderate cases hives and swelling may occur, but more serious cases can involve breathing difficulty, uncontrolled urination and defaecation, shock, and potentially death. These reactions can be an emergency, so if it occurs you should contact the vet as soon as possible.


Treating allergies


Treating allergic conditions can be challenging and frustrating. Removal of the offending allergen, if known, is usually curative, but it can often be difficult to pinpoint the exact cause, especially in the case of atopy.


If your pet is suffering from a suspected allergy, you should visit your vet as they will be able to diagnose the type of allergy and recommend the best treatment options. Antihistamine may be useful in severe allergic reactions, but you should always seek veterinary advice before administering these to your pets.


The first step in treatment is to stop the itching. There are a variety of anti-itch medications available that can be given in tablet and injectable forms, and include steroids amd monoclonal antibody therapy.


Prescription diets are available for allergic dogs. Some of these help support the skin to repair itself and be an effective defensive barrier, while others contain novel proteins and as such are ‘safe’ for dogs with food allergies.


Shampoos, medicated washes and creams may be indicated where skin has become superficially infected. Antibiotics may be indicated in cases where infection has reached deeper layers of the skin.


14 January 2018, 21:10