Guide to allergic skin disease and recurrent ear infections

August 27, 2020

Allergic skin disease

Allergic skin disease can be very frustrating for owners, vets and the patients. It is generally not something that can be cured but is something that will need to be managed throughout the pets life. The most common symptoms are itching of the skin, paws and ears, as well as recurrent ear infections.  

Some pets may experience symptoms only once per year, for example itchiness at the start of spring or summer, whereas other pets may suffer daily from allergies without ongoing management. If your pet is suffering from more than 3 ear infections per year, or if ear infections seem to come back as soon as treatment stops, allergies could be an underlying cause.

Contact allergy results from direct contact with allergens, such as grasses or plants. There will be skin irritation and/or itching at the areas of contact, which is usually the feet, stomach and underarms. Removal or the allergen (once identified) will usually solve the problem, however some treatment may also be required if the itching is severe.

Flea saliva allergies

Flea saliva is a very common allergen. The allergic pet will react to a single flea bite with severe itching and biting, even if the pet doesn’t have fleas itself (such as if a single flea jumps on a dog from another dog in the park). 

The areas most commonly involved are the rump and tail-base region and extending down the hindlimbs. Flea saliva allergies are often worse in the warmer months of the year when fleas are more prevalent. Because one flea can be a problem for an allergic pet, strict flea control is essential to prevent issues from starting. If this is the only type of allergy present, it should be able to be controlled with flea prevention. 

We recommend a product called Bravecto which comes in a topspot (liquid on the back of the neck) for cats and dogs, or a tablet for dogs. The topspot lasts for 6 months in the dog and 3 months in the cat, the tablet for dogs lasts for 3 months. There are some products that do not work as well, such as products from the supermarket – Excelpet, or Frontline. These are older formulations, to which the fleas may have acquired resistance.

Atopy / Inhalant allergens 

Atopy is the name that is used for allergies which occur in a part of the body not in contact with the allergen, for example itching caused by inhaled allergens. The main inhalant allergens are tree pollens, grass pollens, weed pollens, moulds, mildew and house dust mites. Many of these occur seasonally, such as grass pollens however others such as moulds, mildew and dust mites occur year-round.

In humans, these types of allergens cause a respiratory response (“hay fever”), however in dogs and cats the allergy manifests mainly with itchy skin. Most pets start showing signs between 1 – 3 years of age but allergies can also appear later than this. Pets with atopy are often allergic to more than one type of allergen. This type of allergy can be very difficult and frustrating, as most inhaled allergens are environmental and cannot be avoided. The symptoms can be managed by medications; however, recurrence of symptoms is very common due to the difficulty of avoiding environmental allergens.

Treatment options for allergic skin disease

Antihistamines – Very safe to use daily and easy to access. Unfortunately, these do not work in all dogs but do work well in some so are worth trying. Even if they decrease the severity of the symptoms mildly, this may reduce the dose/frequency required of other more expensive drugs, or other drugs with side effects.

Apoquel – A very good anti-allergy drug, with few side effects but can be expensive, especially in larger dogs.

Prednisolone – A cheaper alternative, which works very well against allergies but also affects other organs in the body such as the liver and skin. It often causes side effects such as increased appetite, thirst and urination, and can also make the pet more prone to other more serious diseases such as diabetes and pancreatitis.

Cytopoint – An injection that prevents itching/allergies for 4-6 weeks. Also can be expensive. Useful for animals that are difficult to tablet, or if Apoquel doesn’t work in some patients.

Diet trial – This must be done for at least 12 weeks and the pet must not eat anything else apart from a specific “hypoallergenic” food.

Desensitization injections – There is the option of seeing a specialist for allergy testing, where the pet is tested for what specific allergens it is allergic to, and then desensitization injections are made up specifically for that patient. Success rates vary with this treatment. Approximately 50% of treated dogs will see significant improvement in their clinical signs while approximately 25% more will see a decrease in the amount of medication needed.

Antibiotics and/or ear drops are needed in some cases if there is a concurrent infection, which can commonly occur secondary to allergy due to scratching. This is one of the reasons that it is necessary to come to the vet for your pet to be checked. 

Food Allergies

In dogs, the most common symptoms associated with allergies is itching of the skin. Recurrent ear infections can also have allergies as an underlying cause. In other cases, and often in cats, the digestive system is affected, resulting in vomiting and diarrhoea.

Most food allergies appear after 6 months of age, with the majority of animals affected being over 2 years of age.  A pet with food allergy is often fed the same diet for a long period of time before developing an allergy to it.

Food allergy can develop to almost any protein or carbohydrate component of food. This means that regardless of how good the quality of the food is (reputable brand, home cooked food, grain free) it will still contain proteins which the animal may be allergic to. Furthermore, despite what the label suggests as the “flavour” of the food, most pet foods have a mixture of a number of different proteins (meats). So a food can be labelled as chicken but can still contain beef and/or pork as the main protein content of the food. The most common food allergens are beef, chicken, lamb, dairy products, wheat, gluten, egg, soy, corn, colourings and preservatives.

Treatment options for food allergies

Food allergies generally don’t respond very well to corticosteroids or other medical treatments. Treatment requires identifying the offending component(s) of the diet and eliminating it/them.

The most accurate way of testing for food allergies is with an elimination diet trial using a ‘hypoallergenic diet’. Some of these diets have the proteins in them “hydrolysed” which means they are in a protective bubble & some have the proteins are broken up into amino acids so the body does not recognise & react to the protein.  There are several different commercial foods available (Hills z/d, Royal Canin Hypoallergenic or anallergenic, Delicate Care -skin & stomach).

Alternatively, a home-made diet of a single carbohydrate and a single protein that the pet has never been exposed to before can be fed for the period (such as sweet potato and venison). It takes at least 8 weeks for all other food products to be eliminated from the body, so the pet must eat the special diet exclusively for 8-12 weeks.

This diet trial will not be worthwhile if it is not fed exclusively. All table food and treats must be discontinued during the testing period. There may be reactions from certain types of chewable/flavoured tablets such as heartworm preventative so alternatives should be used during the testing period.

If a positive response and improvement of the pet’s clinical signs occurs, ideally the animal would stay on this diet long term (if home cooked, other vitamins and minerals would need to be added to form a balanced diet). Introducing other foods to a commercial diet after some time may be possible depending on the individual case and can be discussed with the vet. These changes would need to be made very slowly – for example, adding only one new protein every 8-12 weeks.

Contact the Matraville Veterinary Practice if you would like advice on whether a consultation is required for your pet.

Got a question?

We’re here to help you with any urgent enquiries or assistance you might need. Need a little extra help, or not sure if you should bring your pet in for a check-up? Give our team a call and we’ll happily answer your questions.