What is Atopy?
Most people are familiar with the concept of “hay fever” – breathing in certain pollens and other allergens that leads to sneezing and congestion. In animals, however, it is more common for inhaled allergens to cause allergic skin disease than hay fever. Skin disease as a result of inhaled allergens is known as atopy. An animal suffering from atopy has high levels of a type of a reactive antibody called IgE. Normal non allergic animals would produce only low levels of IgE. High levels of IgE antibodies can cause itching, face rubbing, foot licking, sneezing, ear/eye infections, dandruff and skin odour.
There are two effective methods of diagnosing atopy. The first option is IgE allergy testing using a blood sample. This blood test determines the levels of IgE in the blood directed towards specific inhaled allergens. The blood test takes about 3-5 days to complete and costs approximately $275.00.
The second option of diagnosis is intradermal skin tests. This is performed at the a Veterinary Referral Centre. Specific allergens are injected under the skin and the corresponding skin inflammation levels are used to diagnose atopy. This is slightly more accurate than blood testing but involves animals being off medications for several weeks before testing.
Management of Atopy
We know or suspect your dog is scratching because his or her immune system is over reacting to one or more things in the environment. Controlling the signs of atopy can be very, very difficult. What works really well in one dog may not help at all in another dog. Below are listed the most common management options we can try. Often we will need to use more than one at a time.
Up to 50% of dogs will be much easier to control if they are desensitised. Simplistically, this involves injecting small amounts of what they are allergic (ie the allergens) to, encouraging the dog’s immune system to produce normal antibodies (IgG) instead of the allergy antibodies (IgE). Initially the course consists of 15 weekly injections at gradually increasing amounts of vaccine. After this initial phase the injections are given every 3 weeks long term. It may be up to 12 months after starting the “Allergy Injections” before significant improvement is noted. Sometimes the injections need to be continued for several years or longer.
House Dust and House Dust MiteIf your pets has been identified as being allergic to house dust or house dust mite the following tips may help. Highest concentrations usually occur during periods of peak humidity. Mites are concentrated in bedding, stuffed furniture and carpets. Efforts should be directed at thorough regular cleaning of carpeting and matting, covering mattresses with plastic and regular washing and thorough drying of bedding. The new high efficiency vacuum cleaners may help. Ideally the dog should not sleep on cushioned furniture and should be kept in uncarpeted rooms.Mould
Measures to minimise mould exposure include avoiding rooms with high moisture levels, (eg bathroom), decreasing the number of house plants, using a dehumidifier and keeping the dehumidifier clean.PollenPollen concentrations tend to peak early in the morning and at dusk. Avoid fields, keep the lawns cut short, rinse the dog after trips to grassy and weedy sites, keep the dog inside at dusk and dawn and when mowing the lawn.
- Immune suppression
Cortisone tablets or injections are often used for atopic dogs. The aim is to use the lowest possible dose for the shortest period of time. As the animal gets older the condition often becomes more difficult to manage. We can use other immunosuppressants too.
- Flea Control
Flea control is absolutely vital for atopic dogs. This should continue all year round. Ask your veterinarian which product is applicable to your situation.
- Control Skin Infection
Many atopic dogs are prone to recurrent pyoderma (skin infection). We will often try a two to three week course of antibiotics to see if this results in improvement. Antibiotics may need to be used intermittently.
- Yeast Control
A lot of dogs with atopy have a secondary yeast infection in their skin. This can result in scaley, smelly and slightly greasy skin. This will often improve with special anti yeast shampoos. For these shampoos to work they must be in contact with the skin for at least 10 minutes before being rinsed off. Sometimes we use oral medication to control yeast infection.
- Shampoo & Conditioner
Oatmeal based conditioners will decrease the itchiness of many atopic dogs. The conditioner only needs to be lightly rinsed off after application and can be used as frequently as twice weekly.
- Topical Creams
If your dog’s skin condition initially flares up in one or two areas, the progress can be slowed by the topical application of an anti-inflammatory cream. t is often worthwhile having this on hand for early flare ups.
- Essential Fatty Acids
The important fatty acids for allergic skin disease are the Omega-3 and the Omega-6 with a higher than normal Omega-3 and a lower than normal Omega-6 in the diet. The ideal is to achieve a diet with a 5:1 to 10:1 ratio of Oemga-6 to Omega-3 fatty acids. They need to be fed for a minimum of 12 weeks before ascertaining if they help.
Antihistamines help 20-30% of atopic dogs if used in combination with the essential fatty acids. There are four that we routinely will try. We try the first for 2-3 weeks and reassess, then try the second for 2-3 weeks and so on. Occasionally we use them with cortisone to help reduce the dose of the cortisone.
- Elimination Diet.
If we are suspicious your pet has a food allergy, we may recommend feeding an elimination diet. This is quite involved and means feeding your pet a single protein source and a single carbohydrate source for 8 weeks. We will discuss the option in detail if appropriate.
- “Low Itch Diet”
A small number of dogs will benefit from being fed a diet very low in red meat.