Does “hay fever” exist in dogs? A legitimate question that many homeowners can ask themselves; unlike humans, who have rhinitis and conjunctivitis in the case of seasonal allergies, dogs, for their part, mainly show skin symptoms; cases of allergic “colds” comparable to those encountered in human medicine are ultimately quite rare in dogs… on the other hand allergies in veterinary dermatology are very common in the canine species, especially in purebred dogs. Here, you will know about seasonal dog allergies.
An increasingly better understood pathology: canine atopy
There are classically 4 types of allergy in dogs: food allergy, contact allergy, flea bite allergy (DAPP) and seasonal allergy, also called seasonal atopy.
Canine atopy is therefore defined as a hypersensitivity reaction to environmental antigens inhaled or absorbed percutaneously (allergens) in genetically predisposed individuals. The seasonality of environmental allergens makes its clinical expression also seasonal. To put it simply, the skin or mucous membranes of atopic dogs, instead of behaving like an impassable natural barrier, resembles blotting paper.
It considers that about 15% of dogs affect, the age of onset of the first symptoms varying between 6 months and 6 years (however a large majority are between 1 and 3 years). Some breeds are more concerned than others, including Labradors, Golden Retriever, Boxers, Bulldogs, Yorkshires and Westies.
Seasonal allergens mainly concern pollens (trees, grasses, etc.) and their presence spreads out depending on the region from the end of winter to the beginning of the following winter. Mites, dust, feathers… also represent environmental allergens but are not seasonal.
A simplified and unilateral view of seasonal atopy is a major cause of therapeutic failure, even of conflict with the veterinarian: in fact, it is generally a disease with multifactorial origins (genetics, environmental conditions, diet, sensitivity fleas… modifying the tolerance threshold to environmental allergens over time), subject to complications (secondary infections, malassezia…) and for which compliance is sometimes made difficult (long-term treatment, sometimes for life).
When the allergen tolerance threshold will cross, itching appears; the dog scratches, nibbles, licks. The affected areas will be mainly the legs, armpits, flanks, abdomen or head.
The dog who develops seasonal allergies will be allergic for their entire life. It is a chronic recurring disease. However, the intensity of symptoms can vary from season to season depending on the allergen load.
The severity of itching and inflammation of the skin very often lead to infectious complications. The bacteria or yeasts normally present penetrate the cutaneous breaches and develop there, causing even more inflammation and therefore more itching. Among the easily identifiable skin lesions, there are:
- Hair loss
- Bad smell
- Thickening of the skin
Although there is no contagious character to this disease, the infectious complications require strict monitoring of contact with other animals and the owner’s hand hygiene.
In case of itching and complications, a diagnosis by your veterinarian is necessary.
A diagnosis of exclusion
All the difficulty of the diagnosis lies in the fact that there is not a test which allows to affirm with certainty that your dog has a seasonal allergy. The diagnosis is based on 3 essential elements:
- the commemorative (breed, age, environment) and anamnesis (seasonality, response to previous treatments, symptoms observed, etc.) of your dog
- physical and dermatological examination by your veterinarian
- exclusion of other diseases by specific tests or therapeutic trials (primary or secondary pyoderma, external parasites, avoidance diet, hormonal disease, etc.)
Once the diagnosis has been established, allergological tests can undertake, not to confirm the diagnosis, but to prepare for desensitization (immunotherapy), only if the owner wishes to undertake this therapy.
An effective multimodal therapy… but an illusory cure.
As this is a multifactorial disease with a strong genetic component, a total cure is not possible, but suitable solutions exist.
Due to the high frequency of itching complications, it will recommend to treat quickly. This will reduce the processing time and increase its efficiency.
This is the cornerstone of the management of atopy in dogs. Indeed, the goal is to break the vicious circle. Several families of molecules can use, with advantages and disadvantages for each.
- Antihistamines have the advantage of having few side effects and being well tolerated, but are often insufficient for severe allergies.
- Cortisone, used alone or in synergy with an antihistamine, is commonly used as a first-line treatment. Its action is rapid and helps control itching, even very severe. The minimum effective dose is sought, the dose can be adjusted daily. The problem lies in its side effects, or even its contraindications for use; indeed, used over the long term, it predisposes to endocrine diseases and compromises the immune system.
- New generation molecules (immunomodulators, antipruritics) are the best alternatives for long-term treatment; their effect is similar to cortisone with fewer side effects. However, the high cost of these treatments makes their accessibility limited. Management of complications: Preamble to the success of any treatment, it consists in fighting against bacterial and fungal infections. Antibiotic therapy and the use of shampoos and topical products are usually sufficient.
With patience, determination, personal and financial investment, immunotherapy is probably the best long-term alternative. It consists of injecting the incriminated allergens at increasing doses. The goal is to induce tolerance to the pollens that cause the allergic reaction. It is considered that approximately 70% respond favorably to this treatment. The limits concern the restricted spectrum of allergens tested and stabilization over time. Indeed, the tolerance threshold will increase but not annihilate.
The almost systematic involvement of other factors calls for consideration of other therapeutic elements. A reinforced external antiparasitic treatment is essential; a strict hypoallergenic diet and the addition of food supplements (type Omega 3) are strongly recommended; the regular use of shampoos for atopic dogs allowing a restoration of the natural skin barrier, associated with a rehydrating agent, improves the clinical response to other treatments; finally, good aspiration of the living environment and adaptation of outings to places according to the seasons reduce the load of allergens in contact with the animal.
A complex and widespread disease, seasonal atopy needs to well understand by the owner so as not to be discouraged and explore all the therapeutic avenues available. Your veterinarian is at your disposal to guide you and adapt the treatment over time. A significant personal investment on the part of the owner is essential for the success of the therapy.