Dog allergies are caused by the proteins found in dog dander, saliva, blood and urine.

Dander (tiny flakes of dead skin) is continually shed by animals. Proteins that are secreted by oil glands in the dog’s skin are also attached to this dander. Since dogs are constantly shedding dander, allergens are deposited around any area in which the animal is present. Dander is also carried by air currents, even into areas where the dog has not been. In contained areas, such as a home, the accumulation of dander is more likely to trigger an allergic reaction in people with dog allergies.

Saliva, urine, blood and dander allergens are present in all dogs and there is no such thing as a non–allergenic dog. Sensitive people may have an allergic reaction to any dog regardless of hair length or type, size or breed. Small dogs are just as likely to cause an allergic reaction as large dogs.

However, some dogs shed their skin more quickly than others. Poodles and schnauzers shed their skin about every three weeks. Cocker spaniels, German shepherds and Irish setters shed their skin every three to four days. It is possible that the dog breeds that shed their skin less frequently may produce less dander. People sensitive to dog dander will be sensitive to all dog dander. For highly allergic individuals, the actual amount of dander produced by the dog may be irrelevant.