What is an allergy?

It is an abnormal reaction of an individual when it comes into contact with a substance in the environment or in food (allergen).

Symptoms usually involve the skin:

  • Itching (face, paws, ears, armpits, groin, lower belly/thorax, thighs, flanks, around the anus and on the tail);
  • Chronic and recurrent (comes back after having been cured) infections of skin, ears and claw edges:
    • bacterial (pimples, scabs, etc.);
    • fungal (hair loss, redness, crusts, large dandruff, etc.);
  • Hot spot (pyotraumatic dermatitis)
  • Dry and oily skin;
  • Urticaria (bumps all over the body);
  • Vasculitis (inflammation of the blood vessels);
  • Erythema multiforme (swollen annular lesions that look like targets);
  • Furunculosis (deep bacterial infection of hair follicles) on the feet (hemorrhagic blebs, cysts between the fingers), around the anus (fistulas) and/or chin;
  • Lupoïd onychodystrophy (degeneration of claws).

 Those signs may also be accompanied by digestive symptoms in the case of food allergy:

  • Vomiting, diarrhea, constipation;
  • Production of more than 3 stools per day (which become softer and bigger with time); 
  • Flatulence (gas);
  • Tummy ache, burrowing (gurgling), bad breath, tenesmus (effort to produce stool), loss of appetite, weight loss;
  • Pica  (ingestion of inedible objects);
  • Coprophagia ;
  • Diseases of anal sacs;
  • Inflammatory bowel disease;
  • Eosinophilic or lymphoplasmocytic colitis (inflammation of the colon with eosinophils, lymphocytes or plasma cells);
  • Behavioral changes;
  • Anaphylaxis (very severe allergic reaction).

 In Canada, about 6% of domestic animals have allergies.

What are the various types of allergies?

There are the 6 of them :

  • Flea bite allergy
  • Contact allergy
  • Drug reactions
  • Atopy (environmental allergy)
  • Food
  • Seasonal

The information that the pet owner provides and the physical examination are generally very useful for identifying a flea allergy, a contact allergy or a drug reaction.

First, our suspicion of a flea bite allergy might be enhanced by the presence of fleas on the animal. Second, itching and lesions on a very limited area of ​​the skin are often signs of contact allergies. Finally, a drug allergy often causes a very severe sudden reaction of the skin after taking a drug.

The other types of allergies, however, are difficult to differentiate from each other just by the case history and the symptoms because those are the same regardless of the type of allergy involved. In addition, several other reasons can cause the same symptoms (eg parasites, fungi, immune diseases, etc.).

How are allergies diagnosed and treated?

There are 3 main steps to follow to diagnose allergies and to identify which type (s) is (are) involved:

  1. Eliminating parasitic causes by doing tests and giving antiparasitic treatments to the dog. This step is crucial for dogs that go outside as well as for those who don’t; 
  2. Feeding the animal a strict hypoallergenic veterinary diet for 6-12 weeks. During this period, you will need to check if the symptoms disappear or not. 
  3. Doing environmental allergy tests. There are two different tests available: 
    • Intradermal tests. It involves injecting various allergens into the skin of the animal and observing the inflammatory reaction if there is one; 
    • Serological tests. This involves measuring the levels of antibodies against the allergens tested that are present in the blood of the animal. A high number of these antibodies indicates that his immune system is reactive.

 There are 3 aspects to consider in the treatment of allergies. Indeed, we must treat:

  • the cause of the allergy:
    • with antiparasitic agents in case of a flea bite allergy;
    • by not giving the harmful drug anymore in case of a drug reaction;
    • by feeding a hypoallergenic food in case of a food allergy;
  • other skin diseases present at the same time as the allergy:
    • with antibiotics in case of bacterial infections;
    • with antifungals in case of fungal infections; 
  • the allergy itself (one or a combination of the following drugs):
    • with steroidal anti-inflammatory drugs (eg prednisone);
    • with antihistamines (eg diphenhydramine);
    • with antipruritic drugs (eg Apoquel®). This medication eliminates itching;
    • with an immunosuppressant (eg Atopica®). This medicine reduces the immune system’s function;
    • with antibodies (eg Cytopoint®). 

It is also necessary to improve the skin’s ability to stop allergens, bacteria and fungi from getting into the animal’s body. We have a wide variety of shampoos and skin products at your disposal for this.

The point is…

Dogs often come for a veterinary consultation because they scratch a lot. The diagnosis is, however, sometimes difficult to make at first because of the large number of diseases that can cause itching. 

This fact makes it necessary for us to proceed in stages to exclude one by one the different causes figuring on the list of possible causes. It is very important to follow these steps if we want to be able to treat the animal properly, even if the procedure seems long and complicated. 

Your pet is scratching a lot? Make an appointment at one of our establishments so that we can relieve his itching as quickly as possible.