Like HowStuffWorks on Facebook!

What are some signs of pet allergies in infants?

Allergies are the immune system's overreaction to certain substances that are actually harmless. When you're around one of these substances, your body gets agitated and reacts by sending out antibodies to ward off what it perceives as unwanted invaders. Allergies are generally hereditary, which means that if you or your partner are allergic to something, there's a fair chance your baby will be, too. However, you won't necessarily have the same allergy. A pet allergy is generally a reaction to the protein in an animal's saliva or sebaceous glands, or to the animal's dander, which is shed skin flakes.

People usually develop allergies by the time they're ten years old. If you notice your infant has a cold that won't go away, it may be a sign that he's allergic to your pets. Sneezing, a runny nose, red eyes, coughing and congestion are all allergic symptoms, as are some rashes. It's normal for a child to have a cold for a few weeks, but if your baby's symptoms don't go away after a month or two, or if they persist all year round, there's a good chance he has allergies. Even if you get rid of your pet, it might take a while for the symptoms to go away since dander can hang around for months even when the dander source is gone.

If you suspect your baby might have pet allergies, your doctor can help diagnose the problem. An allergist can do a skin test to determine what your baby is allergic to, although skin tests are considered most reliable in children over two years. In a skin test, the doctor pricks your baby with purified forms of a variety of allergens. If your infant is allergic to any of them, he'll develop a little red bump where he was pricked with it.