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All about allergies

From fleas and mites to shampoos and toys, there are many causes of itchy, sensitive skin. Dermatologist David Scarff answers common questions about animal allergies and suggests ways to stop our pets from scratching

What are the main causes of pet allergies, and how can I spot them?

The main sign is scratching, which often results in skin irritation and fur loss. With dogs, there are two predominant reasons: flea allergy (which affects about one in four) and atopic dermatitis, which simply means the skin can’t defend itself well enough against allergens. Typical allergens are house dust mites, pollens, mould spores and bacteria. Around 60 per cent of allergies in dogs are caused by fleas and 30 per cent by atopic dermatitis. In cats, it’s about 90 per cent fleas. Finally, there is contact allergy, when the pet reacts to something they encounter regularly. It’s rare in cats but with dogs, though uncommon, the main culprits are plastic food bowls, toys, shampoo or ear treatments.

My cat grooms a lot. Could an allergy be the problem?

It’s hard to say as some cats just like to groom themselves! However, there are three typical signs of allergy. Cats with a flea allergy will often have hard little crusts on their skin – you can usually feel rather than see these. They may have symmetrical alopecia too – a pattern of hair loss associated with over-grooming, which is common in cats with flea allergy. Parts of the body – the underside, between the back legs, the top of their tail – could look bald. The third sign is lesions on the skin caused by an immune system problem (called eosinophilic granuloma). Atopic dermatitis can look very similar to flea allergy though, so you’d need your vet to make a definitive diagnosis.

Do dogs with an allergy show the same symptoms as cats?

Dogs are simpler to diagnose. With flea allergy, they’ll usually be itchy and will chew at their backs, towards the tail. Some will chew the tops of their tails as they can’t reach the back, but it’s the area over the pelvis that bugs them. Atopic dermatitis is usually first seen in dogs under the age of three, especially Labradors, Westies and Beagles. Suffering dogs might chew their front feet or rub their faces on the carpet as their ears or lips are itchy. With contact allergy, dogs could have soreness, hair loss and itchiness on their face.

My rabbit has flaky skin and the vet says it could be an allergy – what’s causing it?

It sounds like ‘walking dandruff’, caused by Cheyletiella mites. Affected rabbits will produce scale on the skin and it will be very itchy. Rabbits might also suffer from a reaction to an ear mite called Psoroptes cuniculi. This causes the ears to become red and painful, and the rabbit will shy away from contact. Both mite allergies need to be treated by killing the parasites with vet-prescribed products containing Ivermectin. All rabbits living together need to be treated so that they don’t reinfect each other.

Do dogs get hay fever?

Some dogs suffer with hay fever-like symptoms when the pollen count is high. The materials in pollen are often absorbed through the dog’s paws and skin and can cause an itchy allergic reaction. Dogs may get infections in their skin from the scratching and have the urge to rub their faces on the carpet. You can help reduce symptoms by wiping your dog down with a damp towel when they’ve been outside, which helps to remove pollens trapped in their coat and on their paws.

If a cat is fussy about their food, could it be an allergy?

Many cats are faddy, and food allergy is relatively uncommon. Elimination diets (where just one food is fed for a while, with other foods reintroduced one at a time to find the culprit) may help with diagnosis. However, cats can suffer deficiencies if fed a limited diet for a long time. Some cats are sensitive to hypoallergenic diets, so if a food allergy is suspected, dermatologists will generally recommend a home-cooked diet. You can read more on pet food allergies and elimination diets here.

A friend’s dog collapsed after a reaction to a bee sting – is this something I should worry about?

It’s quite rare, but if a dog has been stung and collapses, they need to see a vet straight away. Puppies who chew a bee can have a reaction where their faces swell, causing breathing difficulties, so the owners may carry an EpiPen (adrenaline jab) in case it happens again.

Can allergies be reversed?

No, you have to eliminate the cause. Whether it’s fleas or mites, you must treat the parasite. If your pet is suffering with atopic dermatitis and you’ve been able to determine the allergen, your vet may use desensitisation vaccines. Some people get rid of their carpets if their pets have a dust mite allergy. With contact allergies, swap your plastic food bowl for a ceramic one or try using a different shampoo.