Allergic to Dogs and Allergies in Dogs Resource

What is an Allergy?

We can now arrive at a richer definition of an allergy through having understood the basic principles of the immune system, allergens and antigens, antibodies (Immunoglobulins) and hypersensitivity. Further insight can be gained by appreciating the allergy response mechanism (sequence of events of an allergy reaction) and the role played by chemical mediators or signaling molecules associated with allergies e.g. cytokines (chemokines, interleukins, lymphokines), eicosanoid inflammatory mediators (leukotrienes and prostaglandins) and histamine.

What is a Classic Allergy?

What is an Allergy

Thus, 6 aspects to consider concerning a ‘typical’ or classic allergy are:

  • The individual will experience a Type 1 Hypersensitivity (immediate hypersensitivity) reaction.
  • The individual will be predisposed to having an allergy (atopy). This means they have a genetic predisposition/tendency to develop an allergic disease. (See also: Do Allergies Result From Nature or Nurture? )
  • The immune system of a presensitized individual mounts an amplified response when re-exposed (second or subsequent contact) to the antigen. An antigen that triggers an allergy response is termed an allergen.
  • The immune system will respond to the antigen by producing a class of antibodies/Immunoglobulins (Ig) known as Immunoglobulin E (IgE).
  • Various inflammatory chemical mediators may be involved.
  • The allergen will be non-parasitic in nature.

Therefore, an allergy, such as one triggered by pollen or dog dander, can be defined as:

“A Type 1 Hypersensitivity (immediate hypersensitivity) reaction in a predisposed and presensitized individual due to the response of Immunoglobulin E (IgE) and various inflammatory chemical mediators to a non-parasitic antigen”


What About Other Allergic Responses?

As was noted in the section concerning Antibodies (Immunoglobulins), Hypersensitivity and Allergies, hypersensitivity responses are typically grouped into 4 types. The term ‘hypersensitive reaction’ is synonymous with ‘allergic reaction’. Therefore, aside from the classic allergy Type 1 Hypersensitivity response, a range of other types of allergic reaction are possible and these do not necessarily exist in isolation of each other.

With regards to dog allergies, people allergic to dogs will be allergic to dog allergens (Type 1 Hypersensitivity), whereas a dog may experience various types of allergic response. For example, a dog may have an allergy to pollen (Type 1 Hypersensitivity) but may also have the potential to experience other Type 2, 3 or 4 allergic conditions e.g. canine autoimmune hemolytic anemia, rheumatoid arthritis or allergic contact dermatatis.

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