Atopy is an allergic condition in pets. It is thought to be inherited, and is usually first seen between 6 months and 4 years of age, although possible from 3 months to 7 years. Susceptible animals become allergic to pollens (grasses, trees, weeds) house dust mites, mould and fungal spores, wool, flea saliva antigens, and become intensely itchy when exposed to their allergen(s). Allergy is usually due to a range of allergens.
Signs Of Atopy
The signs of atopy are generalised itching (ie. itchy all over). Dogs are especially itchy around the ears, under front legs, groin & inside of hind legs, feet, around the eyes and on the belly. Mild cases have only one or two affected areas, while more severe cases involve them all. Cats are usually most itchy around the head. Initially the itch may come and go with seasonal changes in pollen numbers and types. Over time this seasonal pattern often becomes year round.
The intense itchiness causes the animal to chew, scratch and bite resulting in inflammation/redness of the skin, hair loss, brown saliva staining of the fur from licking (especially seen on front feet), scaling, crustiness, darkening and thickening of the skin, ulceration and secondary skin infections. Inflammation and redness of the eyes may develop from animals rubbing these and recurrent ear infections are also very common (as the ears are lined in skin, which is affected).
Diagnosis Of Atopy
The diagnosis of atopy can be made after we have seen a pet more than once with itchiness, or in severe cases involving most of the usual affected areas of skin. Other possible causes of the itching are food hypersensitivity, flea allergic dermatitis, mange mites, yeast infection of skin, or contact irritation.
The veterinarian will examine your pet, and usually perform skin scrapings, ‘sticky tape’ preparations, and/or ear smears to examine under the microscope or send to the laboratory. In some cases we will request you undertake a food allergy trial to rule out this possible cause (or contributing cause) of the itchiness.
Treatment Options For Atopic Pets
It is important to understand that atopy and allergies are generally not curable, but rather a disease that can be managed, to help keep your pet more comfortable. The one exception to this is hyposensitisation (see below under Referrals).
Treatment recommendations are based on the severity of clinical signs. Mild cases can often be managed with oral antihistamine tablets. We may have to work through a few different types of these before we find one that works well for your pet, trialing each for around 10 days.
Advantages of using antihistamines include being non prescription, so once an effective medication is determined they can be purchased over the counter from us without a consultation. They are administered as needed not as a course, and have few side effects: drowsiness (seen initially but most patients develop a tolerance to this after a short time) and increased appetite.
More severe or chronic cases with inflamed irritated skin are usually treated with corticosteriod injections and tablets. These settle the inflammation and itch, allowing healing as the pet leaves the area alone. Short term use of these medications as prescribed by your veterinarian is fine, however high doses and long term use can result in side effects of immune suppression with an increased susceptibility to infections, increased hunger, thirst, and urination, muscle weakness, thin skin and hair loss.
If secondary skin infections are present (which are common), antibiotics and specialised shampoos may also be prescribed. Most atopic pets are extremely sensitive to flea bites, so a regular good quality flea treatment like monthly Nexgard, Comfortis or 3 monthly Bravecto is important. We recommend all atopic patients and their housemate pets be treated.
This is because although the housemate pets may not be affected by flea bites, they are carrying fleas which will bite the affected pet. Many patients have their overall itch level reduced by good flea control, including oral fatty acid supplements in their diet, or by using special anti itch shampoos & conditioners such as Epi-soothe, Resi-soothe or Aloveen.
Ear infections are frequently present and need to be treated with ear drops or oral medication.
Referral
Atopic patients have the option of referral to specialist veterinary dermatologists. We sometimes recommend this for severe cases, especially those with a year round pattern, and those that are difficult to control. Dermatological specialists may perform a skin patch test to identify the allergens involved, and try to reduce your pets response to these through hyposensitisation.
Hyposensitisation involves a course of injections of the allergens at gradually increasing doses over a long period, to ‘train’ the pets immune system to respond normally rather than excessively when exposed to these naturally in the future.