What's in the Air? The Complete Guide to Seasonal and Year-Round Airborne Allergies

Introduction The Allergy Boom and the Hygiene HypothesisNot everyone is programmed to develop allergies. You have to inherit the tendency. If you have close family with a history of hay fever, asthma, hives, eczema, or specific food or drug allergies, there is a chance you will develop allergy symptoms.When I was twelve, I baby-sat at a home where there was a cat. Until that time I had very limited exposure to cats, so I happily played with it. After a short time my eyes started to itch, so I rubbed them. Before I knew it, both my eyes were swollen and I could barely see. This was my introduction to allergies.At that time I lived in Rochester, Minnesota. My family had moved there from Belfast, Northern Ireland, when I was ten. Shortly after the baby-sitting incident, I started to develop sneezing and a runny and stuffy nose in the late summer. The Mayo Clinic scratched my back with multiple substances and told me I was allergic to ragweed -- "the king" of the pollens in the Midwest from August 15 to the first frost. There was no ragweed in the United Kingdom and it took me two seasons in Minnesota to develop the allergy. I had lots of company sneezing and sniffling away every September.The main treatment then was Chlor-trimeton, an antihistamine that made me snooze through my classes, so generally I just suffered with my tissue box at hand. My parents then told me that they had had allergy-related problems in the past. My father had hives as a child and my mother had asthma as a teenager. They both "outgrew" their allergies. Meanwhile, I was sneezing and itching and my brother was blissfully unaffected. Why me?Just because my father had hives as a child and my mother had asthma as a teenager did not mean I was programmed to get these specific allergy problems. Instead, I inherited a tendency to get any one of the various types of allergies. In my case, this turned out to be nasal and eye symptoms from cats and ragweed pollen.Your immune system is like your body's homeland defense system. It guards you against foreign invaders such as bacteria or cancer cells. Occasionally it mistakes itself for a foreign invader, reacting against part of your body. This causes autoimmune disease. In the case of allergy, the immune system overreacts to innocent substances such as cats or pollen particles in the air. Normal, nonallergic people don't overreact to these substances. But if you are allergic you end up with sneezing, runny or stuffy nose, and teary eyes.The human immune system is a giant network. Think of it as a road map showing different routes. Some paths protect us from foreign substances such as infection and cancer. One of the main routes, however, leads to allergies. If you are programmed to be allergic, inhale a speck of dog allergen and your immune system will crank out quantities of a chemical called immunoglobin E (IgE). The IgE charges through your bloodstream and sticks to special cells in the lining of your nose, throat, and lungs. It then acts as a sentry. If it encounters dog allergen again, it tells the cell to pump out powerful chemicals such as histamine. These chemicals make your nose and eyes run and cause itching and inflammation, among other symptoms.The same reaction can happen in the lining of the eyes, causing itching and swelling. In the lungs it causes asthma. If the allergy is severe and the allergy substance is inside the body (food, medicine, or a bee sting), the reaction can occur throughout the body resulting in hives or a life-threatening reaction called anaphylaxis, which can result in airway swelling and difficulty breathing. IgE, the "allergic antibody," is normally present in very low levels, but is found in larger quantities in people with allergies.Allergies also wax and wane. A childhood allergy to inhaled substances often goes away, but others may later appear. In my case, I lost my allergy to ragweed but later developed onShepherd, Gillian is the author of 'What's in the Air? The Complete Guide to Seasonal and Year-Round Airborne Allergies', published 2002 under ISBN 9780743442176 and ISBN 0743442172.