Allergic children are predisposed to allergies to new substances. A casual encounter, such as visiting friends who have a pet, may not be enough to sensitize a child; but continued, massive exposure to an animal will often do so. Unfortunately, this sensitization frequently takes one to two years, which means that the new allergy becomes evident just as the pet becomes an integral part of the family, and just when separation is the most traumatic. The best advice is simply not iave a dog, cat, or other fur-bearing animal in a home where a ily member is allergic. Some pets that are safe for allergic farn-i are tropical fish, turtles, chameleons, iguanas, and snakes.

The allergen from dogs or cats that causes an allergic reaction is not present in the hair of the animal, but rather in the dander, or flakes of the animal’s skin. Is it all right to have a pet if it is outside most of the time? It takes only a few minutes for sufficient dander to accumulate on carpets and furniture. This is why allergic individuals have problems even when a pet is kept in the basement. When the pet is removed from the house, and after thorough cleaning, it may take up to four weeks for the dander to dissipate.

Allergy injections for sensitivity to animal dander are not advisable except in unusual circumstances. One circumstance is the blind per­son who becomes allergic to a seeing-eye dog; another is the small-animal veterinarian who becomes allergic to house pets. The most effective course of action is to remove the pet from the environment.

No one is allergic to a substance the first time it is encountered; a period of sensitization precedes the onset of the allergy. Two years is a typical period, though some allergies appear sooner and some later.