Studies show that approximately 15 percent of the population is allergic to dogs or cats. An estimated one-third of Americans who are allergic to cats live with at least one cat in their household anyway. When advised by their physicians to give up their pets, only one out of five did.

Since all cats and dogs have skin, there are no non-allergenic breeds. The source of irritation to pet-allergic humans? Glands in the animal's skin secrete tiny allergy-triggering proteins, called allergens, that linger in the animal's fur but also float easily in the air.

Allergens are present in the animal's saliva and urine, too, and may become airborne when saliva dries on the fur. The severity of reaction to these allergens varies from one person to the next, ranging from mild sniffling and sneezing to life-threatening asthma, and can be complicated by simultaneous allergies to other irritants in the environment.

It is often difficult to avoid the allergens that can come from other people's pets or be transported by people who have been in contact with animals. School classes can be overloaded with pet allergens.

Pet owners should know it is important to avoid their allergens because of the increase in the risk of developing, or worsening, asthma. The symptoms can be controlled with medication but the allergy itself cannot be removed.

For people who have only one allergy, it may be possible to have a tolerance treatment. This desensitisation treatment is a vaccination against the allergen. Exposure to the allergens several times in a period of up to five years will be necessary.

Most often the allergies are to cats or dogs, but rats, mice, guinea pigs, hamsters, pet birds, horses, cows or poultry can be involved.

In short, forget about trying to make your pet "non-allergenic." If your allergies are severe, it is best to stick with reptiles or fish for pets. Having pets has been shown to be emotionally healthy. However, if you have anything other than a mild allergy, your allergies should be addressed first.

Be considerate of others when thinking about having a pet. You may get along with the pet, but will others who come to visit or stay with you. Remember, if your single and looking for a long term relationship, having a pet reduces you chances of that happening.