Some Facts1. Canine Atopic Dermatitis is a genetic predisposition to develop allergic symptoms following repeated exposure mostly to inhaled and contacted allergens.
2. Age of onset of allergic symptoms is usually between 1 and 4 years of age. Symptoms may be seasonal or all year round. They tend to become worse with age and have a longer season as the dog ages.
3. Several breeds have a higher incidence, particularly Jack Russells, West Highland Whites, Staffordshire Bull Terriers.
4. Common causes include pollens (trees, grasses and weeds), mould spores, house dust mites, wool, cat dander, feathers.
Clinical SignsThe primary clinical signs are scratching, biting or licking, most often under the arms, face, feet and lower abdomen in dogs. Hair loss, redness, scaly skin, bad odour and darkening of the skin are often associated. Other symptoms may be recurrent ear infections, conjunctivitis and skin infections. Symptoms progressively worsen with time.
DiagnosisOther skin problems that need to be ruled out include food allergies, flea bite allergies, mites.
The two main useful tests are intradermal skin testing and a blood allergy test. The results of these tests may be used to formulate a hyposensitizing vaccine.
TreatmentNo single treatment tends to be effective alone. A combination of therapies is required and most dogs require life long measures for control as complete elimination of the allergens can be impossible.
1. Control Secondary Infection
This is an important initial step in treatment. Secondary infections sometimes contribute greatly to the itchiness of the dog. Antibiotics, antifungals and medicated shampoos can all be used. Medicated shampoos are then used for maintance control of organisms on the skin. It is advisable to also use a “leave-in” condition such as “Aloveen” or a conditioning rinse such as Alpha-keri bath oil (10mls in 2 litres of water rinsed over dog).
2. Flea Control
Strict flea control is essential for all dogs with atopic dermatitis. A single flea can severely exacerbate the allergic symptoms.
3. Control the Itch
This can be done by antihistamines or glucocorticoids. It is preferable to administer glucocorticoids orally on alternate days to minimize side effects. Long term usage may increase susceptibility to other conditions. Antihistamines will sometimes control itchiness alone (only in about 10% of cases) and sometimes work in conjunction with glucocorticoids to achieve control
4. Hyposensitisation (Allergy Vaccine)
a. This involves giving allergy vaccines usually for the life time of the dog.
b. An initial series of injections, usually every 3 days for 6 weeks, is given
c. Periodic boosters are usually required every 1 to 4 weeks. If scratching is seasonal, the vaccine may not be given all year.
d. Expected response time: 25% within 3 months, 50% in 3-6 months, 25% within 6-12 months.
e. Expected response rate: 60-65% of dogs hyposensitized will be controlled satisfactorily with the allergy vaccine.
5. Omega 3 and Omega 6 Fatty Acids
Specific fatty acid supplements will result in improvement of symptoms in 20-30% of dogs. They are commonly used in conjunction with other forms of treatment. We recommend “Megaderm”
This drug can be a useful alternative to glucocorticoids as it is more specific and has less long term side effects. However it is quite expensive and it is important that all other aspects are controlled prior to its use.