Dog - Allergic Skin Diseases

What are allergies and how do they affect dogs?

Allergic reactions are very common in dogs and are fully described in a separate handout on Allergies and hypersensitivities.

Is there more than one type of allergy?

Yes, there are at least five common types of allergy in the dog:

1. Flea
2. Food
3. Contact
4. Inhalant
5. Bacterial hypersensitivity

Allergic skin diseases are among the most common, difficult and frustrating conditions to diagnose and treat in veterinary practice. Four major groups of allergens (the substance that causes the allergic reaction) are identified which can result in skin problems.

• Flea saliva
• Food constituents
• Inhaled particles such as dust or pollen
• Contact allergies (allergies arising from touching the allergen)

Contact allergens include many substances ranging from plant materials to disinfectants, wool, nylon and dyes etc.

Urticaria

Urticaria (hives) is an allergic phenomenon that can result from food, drugs, vaccines, insect bites, stings etc. Single or multiple weals or swellings of variable size suddenly appear on the skin. Some types of dogs appear to be more susceptible than others.

Flea allergy dermatitis

Many dogs are allergic to proteins in the saliva that the flea injects in order to obtain a meal of blood. In a sensitive dog this causes itchiness sometimes resulting in very extensive inflammation (dermatitis).

Once sensitised, due to the hypersensitivity reaction, often the dog needs to receive one flea bite to trigger the reaction, which results in continuous pruritus (itchiness).