Many of us have to reach for anti-histamines and tissues as we sneeze our way through the spring and summer. It seems as though allergies are becoming more and more prevalent, and our pets can also be affected. Allergies to parasites, food and substances in the environment (also known as ‘Atopy’) are commonplace, and this week’s article will discuss ways to recognise and manage these problems in our canine companions.
What is an allergy?
An allergy or allergic reaction arises when the immune system over-reacts to a substance in the environment, causing one or more typical symptoms:
- Itchy and red skin
- Excessive scratching
- Hair loss
- Rashes and/or spots
- Red, itchy ears and/or feet
- Excessive licking of feet
- Red, runny eyes
- Soft motions or diarrhoea
All dogs can be affected, but some breeds of dog are more prone to developing allergies than others. Those breeds which are over-represented include the West Highland White Terrier (Westie), Labradors, Retrievers and Boxers, amongst others.
What are the most common allergy triggers?
An allergy can arise to almost any substance encountered in the environment, and therefore the list of causes of allergies is huge. These can be split into a few main groups:
- Parasites- fleas and mites most commonly
- Food- different proteins and carbohydrates are implicated
- Outdoor allergens- pollens, grasses, trees
- Indoor allergens- house dust, human skin dander, other animal fur, cleaning products and cigarette smoke
- Medications- prescription drugs and therapeutic shampoos
- My dog is itchy! How do I know if this is caused by an allergy?
All dogs scratch from time to time, but if this scratching becomes excessive and obsessive then this may indicate a problem. It is important to get your dog checked by your Vet if you are concerned, since early assessment, diagnosis and treatment can help prevent chronic damage to the skin, ears and eyes.
As we have mentioned, parasites can be one of the main allergy triggers, but it is important to remember that the physical presence of fleas on the skin and mites burrowing in the skin commonly causes itchiness without an intense allergic response. As part of a full physical examination, your Vet will check your dog for the presence of these parasites, and may want to perform a skin scrape or blood test to help rule out mites as part of the problem (see our previous blog post on Fox Mange; https://www.richmondvets.co.uk/facts-on-fox-mange/). Using regular, effective parasite treatments are a vital part of any preventive health routine, and our trained staff here at the surgery are at hand to advise you on the most suitable product for your pet.
If the physical presence of parasites has been ruled out, it is still advisable to continue with regular, preventive parasite treatments, since those dogs which are allergic to fleas in particular, can experience intense prolonged itchiness after being bitten by a single flea! This is why if your dog shares his or her home with a feline companion, it is important to remember to use flea prevention for the cat too, since cat fleas readily cause symptoms of itchiness in dogs which are sensitive to their bite.
Following on from investigating and treating parasites, the presence of persistent, chronic symptoms of allergic disease, in any combination from the list above, will lead your Vet to consider investigating further for causes. Taking a thorough history is important, since some symptoms may be seasonal, appearing only at certain times of the year, and this may point to identifying an environmental cause. If the onset of symptoms coincides with changes in diet, treats, cleaning products or shampoos, this may point towards a cause.
Specific tests to identify allergy triggers include:
* Exclusion diets, where the dog is fed a simple diet usually consisting of one novel protein source and one carbohydrate source for a minimum of 12 weeks, to the exclusion of all other treats, tit-bits or human food. Prescription diets are available but sometimes preparing a home cooked diet may be necessary. If symptoms improve, individual food sources can be re-introduced into the diet to see if they trigger allergic symptoms. Some dogs may have intolerances to certain food stuffs rather than allergies, and exclusion diets can help determine these too.
* Intra-dermal skin tests. These involve injecting small amounts of allergen into the dog’s skin and recording any reaction at the site of the injection.
* Blood tests. Less reliable than intra-dermal skin tests, but still very effective at detecting allergies to airborne allergens in the environment. These tests look for antibodies in the blood stream.
My dog has been diagnosed with allergic skin disease. What can be done?
Allergies are many and varied, and therefore it is important to realise that the most effective regimes to control an allergy in a dog will be tailored specifically to that dog’s particular needs. Avoidance tactics, preventive measures and therapeutic medications will be used in different combinations depending on the outcome of history taking, physical examination and allergy testing. General principles are as follows:
Effective, regular parasite control, treating all animals in the household.
Feeding a diet free of any allergens identified as problematic through diet trials and allergy testing.
Avoiding any problematic environmental allergens. This is not easy! Avoiding areas with long grasses can be appropriate in many cases. If cigarette smoke is implicated, stopping smoking in the house may be appropriate.
Measures to keep down levels of house dust and house dust mites, including daily vacuuming and the use of environmental household sprays.
Supplementing your dog’s diet with sources of essential fatty acids (Omega 3) to reduce the harmful effects of histamine released during an allergic response. There are many veterinary products available including Dermoscent and Viacutan, and our staff can advise you on the most effective.
Topical veterinary shampoos and washes can be very useful to soothe itchy skin, enhance the protective barrier of the skin and can also help prevent secondary bacterial and fungal skin infections.
Immunotherapy- this is a strategy to help desensitise a dog with allergic disease, using allergens identified as problematic through intra-dermal skin testing or blood tests. Regular injections of a combination of altered allergens can prove very effective at controlling chronic, severe allergic symptoms.
Medication- anti-histamines, antibiotics, steroids and other immunomodulatory drugs, when used in the correct doses and combinations can prove very effective. Sometimes these medications can be used topically. Your Vet will discuss the right combination for your dog, if appropriate, along with discussing the risk of any side effects.
Allergies are appearing to cause our canine companions more problems. However, our armoury in the fight against the causes and symptoms of allergies is also expanding, and the vast majority of cases can be managed extremely effectively. If you have any concerns regarding allergic disease in your dog, don’t hesitate to contact the surgery where one of our Vets can advise you on the best course of action, and discuss which techniques or products may be most suited to your dog’s particular problem. That way we can all enjoy the warm weather together, while it lasts!
As our special offer for the month of July 2013, we have discounted the cost of Viacutan and Dermoscent for our clients with itchy dogs and cats. Please enquire in clinic for further details.