Dogs may experience itchiness for a range of reasons and it may only become an issue if the itching becomes excessive. Common causes for itchiness include parasites such as fleas and lice, contact irritants, food allergies and yeast infections. However, dogs can develop allergies to substances, which we call atopic dermatitis, or skin allergy.

It is important to remember that even if your dog is diagnosed with skin or food allergies it is still necessary to control parasite problems, which will only make scratching worse.

Skin allergies usually develop in the first three years of a dog’s life – they are not born with an allergy but develop it after contact with an allergen. A disorder of the dog’s immune system will cause it to over-react in the presence of these allergens and release histamines, which lead to itchiness.

Some breeds are more commonly affected, such as West Highland white terriers, Lhaso Apsos, English and Irish setters, retrievers, Dalmatians, bulldogs, boxers and German shepherds. Some cross breeds can also be affected. Affected dogs should not be bred from.

Signs of atopy

  • Chewing on feet
  • Rubbing the face on the carpet
  • Scratching, especially the groin and armpits
  • Hair loss
  • Recurring ear infections

Scratching can disrupt healthy bacteria on the skin, which allows secondary infections with bacteria and yeast to occur. This causes further scratching, and is known as secondary pyoderma.

Some dogs may only have a seasonal allergy to begin with, especially with tree pollen allergies which may only be a problem for a few weeks of the year.

How do we determine what your dog is allergic to?

  • Skin allergy testing is the gold standard for diagnosing allergies, but can be expensive.
  • Blood sampling is a more affordable option which covers common indoor and outdoor environmental allergies.
  • There are no accurate food allergy tests for dogs, so we will often implement a food trial – either home-made or commercial.
  • Common indoor allergens include dust mites, flea dirt, grain mites, mould and storage mites. Outdoor allergens include various grasses, tree pollens, weeds, nettle, plantain and mugwort.

If your pet is showing signs of allergies, book an appointment to see your vet.

Can we change the dog’s living circumstances to avoid allergens?

There may be a range of measures you can take to lessen the effects of the allergy around your home.

  • Avoid having pollinated flowers, perfumes, sprays, plug-ins and aromatherapy candles in the home, and avoid using washing powders and fabric conditioners on dog beds.
  • House dust mites are a common allergy, so avoid having your dog in your bedroom – a typical human mattress can hold between 100,000 to 10 million mites.
  • Putting your dog’s bed out in the sunshine on a daily basis can reduce dust mites. There are sprays that kill dust mites in the environment. You can also avoid stuffed toys, hoover regularly and empty the bag after every use.
  • If your dog is allergic to mould, keeping them out of damp areas such as basements and garages may help.
  • Keep pet food in a sealed plastic container with a lid and not in the bag.
  • In the case of a grass allergy, keep pets indoors while the lawn is mowed. Keep dogs out of fields and rinse their feet off after they’ve been outside. Keep them indoors when the pollen count is high.

Treatment

It’s important to remember that there is no cure for atopy, meaning we are often looking for control of the problem rather than a solution.

Often a combination of treatments are needed – such as dietary alteration, antihistamines, fish oils, steroids, shampoos, immune-modulating drugs, antibiotics and antifungal drugs.

Injections – can be administered monthly of a monoclonal antibody called Cytopoint, which interrupts the inflammatory pathway to stop itching. This appears to be very safe and effective, and is becoming the mainstay of treating atopy.

Immune modulating drugs – these tablets, such as Apoquel, can work well but can be expensive and may occasionally have side effects.

Steroids – these often give instant relief but are not ideal long-term because of side effects. Steroids should never be suddenly stopped – weaning off gradually is preferred.

Shampoos – a whole range are available, and our team can discuss which is most likely to help in your dog’s specific case.

Antihistamines – we often try these in dogs, but they are less effective than in humans.

Hyposensitisation injections – once we know what your dog is allergic to, an individual vaccine can be made for the allergens. Your dog is given a weekly or monthly injection of a low dose of the allergen. Their immune system will hopefully begin to accept these allergens and your dogs’ itching will settle.

Supplements – some dogs improve with fish oils, krill oils or evening primrose oil. You would not expect to see any signs of improvement until after at least four to six weeks of treatment.

Treatment of the secondary bacterial and yeast infections are also often necessary. Shampoos can often help with these infections.

Trials to diagnose food allergies

Remember that dogs must be exposed to an allergen for some time before the allergy develops, so if we feed a patient a protein they haven’t eaten before, it will not be immediately allergic to it.

So, with a food trial we feed a very restricted diet consisting of one protein source and one carbohydrate source that the dog has never had before for a period of six to eight weeks. Access to water should be provided, but no milk, treats or human food should be made available during this time. It’s very important that you stick strictly to the test diet – no treats or snacks!

If the skin improves within this time it suggests a food allergy.

Food trials can be undertaken with a home-made diet, for example with salmon and potato, fish and tapioca, venison and turnip, duck and pasta etc. However, this can be time consuming, although making food up in batches and storing in the freezer helps.

Because of this, hypo-allergenic commercial diets are often used – these sometimes do not work, but are easily available .

In many cases, hydrolysed protein diets can be fed, which have the protein broken down in such a way that the immune system can’t react to them. These ready made diets are very easy and convenient to use. The dried kibble can also be used as treats if you need to use them for training. If you are interested in finding out more, please speak to your vet as it’s important you use the correct one.