What is environmental atopy?

Environmental atopy is a hereditary condition in dogs caused by an abnormal immune response to environmental allergens, as well as a weak or damaged skin surface barrier. Contact with the allergens, which are often normal environmental proteins such as pollens or dust mites, causes an excessive production of antibodies in affected dogs, which then cause the symptoms that you will see as an owner. The symptoms of atopy will typically arise before the age of 3 years, with some breeds particularly prone to the condition. These include West Highland White Terriers, Labradors, Shar Peis and Bull Terrier breeds, to name just a few. Often, allergies will start as a seasonal problem over spring and summer, but can become more permanent throughout the year with time.

Diagnosis of Environmental atopy

Diagnosis is difficult as there is no single test to diagnose the condition. Other causes of itchiness need to be ruled out, and this can require several visits and different tests.

Common diseases to exclude:

• Ectoparasites (fleas and mites). These are the most common cause for itchy skin. It is not always possible to see evidence of fleas/mites by eye, or even with combing. To rule out parasites, we may need to perform skin scrapes, hair plucks or occasionally skin biopsies.
• Food allergy/dietary atopy. ~25% of dogs with itchy skin can be linked to a food allergy. To rule out a food allergy we must perform a diet trial, during which, your dog can ONLY eat a specific type of diet for a minimum of six weeks.

Intradermal Testing

If a diagnosis of atopy has been reached, it can be helpful to identify what your dog is allergic to. This can be done by injecting small amounts of the allergen into the skin and recording the skin’s response. This is known as Intradermal Testing (IDT). A blood test can also be used to measure antibody levels to different potential allergens; this is called serology.

Symptoms of Environmental atopy 

• Itchiness (pruritis): sratching, chewing feet, excessive licking, rubbing affected body parts, scooting, shaking head, scratching ears. chewing and licking will often lead to brown saliva stained paws.
• Reddened skin (erythema).
• Secondary bacterial skin infection (pyoderma). Spotty skin/pustules, weepy skin, crusty spots.
• Secondary yeast overgrowth. Greasy, smelly coat.
• Recurring/chronic ear infections (otitis externa). Head shaking, scratching at ears, excess ear wax, reddened skin in ears.
• Recurring/chronic anal gland problems.
• Scooting or chewing at back end.
• Hair loss (alopecia).
• Darker or thickened skin.

Management and Treatment

We can control Atopy without drugs in the early stages, but some situations may require medication from the beginning. The treatment plan will depend on the severity of signs.

• Allergen avoidance: Reducing exposure to potential allergens as well as maintaining strict preventative parasite control is crucial.
• Treatment of “flare factors”: Soothing and antibacterial/antifungal shampoos are very important in managing the condition. Occasionally, it may also require antibiotics. In some cases, regular shampooing may be the only form of treatment you need.
• Prescription diets: We specially formulate these to improve skin health and reduce pruritus.
• Essential fatty acids: These should be given to any dog with atopic dermatitis. They help to provide healthy skin and a strong skin barrier.
• Allergen Specific Immunotherapy (ASIT): After intradermal testing, we can create a vaccine for your pet which contains the specific allergens your dog is allergic to. This can effectively reduce sensitivity to the allergen in 50-80% of cases. It may take 3-12 months to see a positive response and you will need to give lifelong.
• Anti-itching drugs: Oclacitinib (Apoquel) – Rapid effect and has fewer side effects than corticosteroids or cyclosporine. Corticosteroids – Useful for acute (short term) cases as they work very quickly and provide effective relief, however, there can be substantial side effects long term. We can avoid many of these side effects by applying directly to the skin via a spray or cream. Topical corticosteroids can therefore play an important role in controlling your pet’s atopy. Cyclosporine (Atopica) – Very effective but more expensive. It has a slower onset, so we often give in conjunction with steroids initially. Antihistamines. These may, in limited cases, have some beneficial effect.

Atopy is a life-long skin disease, which we are only able to control rather than cure. Careful management can reduce symptoms and dramatically improve the quality of life for your dog. Reaching a correct diagnosis is crucial. Treatment is usually life long and can involve significant commitment in terms of regular visits to your vet, expense, and administration of various treatments. Good control of flare factors such as overgrowth of bacteria and yeast is a very important aspect of managing this condition.

If you have any questions regarding atopy in dogs, or are concerned about your own pet, please contact the practice on 01626 835002.