An allergy results when one of your body's natural processes runs amok. Most other diseases or disorders have causes such as the invasion of bacteria or viruses, the runaway growth of cells, the deterioration and failure of an organ, the blockage of a duct or vessel, or any one of a number of other things that can go wrong. An allergy occurs when the body's immune system, which is designed to fight disease, works too well and attacks an otherwise harmless substance.

 

How it works

The immune system produces immunoglobulin E (IgE), an antibody that circulates through the bloodstream. Certain otherwise harmless substances - let's say a food like strawberries - can trigger the creation of large amounts of IgE. When this is released, it attaches itself to mast cells, which occur in all body tissues, but especially in areas typical of allergic reactions, such as the nose, throat, lungs, skin and gastrointestinal tract. These mast cells release chemicals called histamines, which cause the symptoms such as itching in the mouth, formation of mucous in the nose and throat, trouble breathing or swallowing, itching and/or hives on the skin, and even abdominal pain, vomiting, or diarrhea.

 

For some people who have severe allergies - for example, to peanuts or bee stings - the reaction can be immediate, catastrophic, and life-threatening. This is called "anaphylaxis." These people go into bronchospasm and begin to wheeze. The air passages in their lungs narrow, and they gasp for breath. Their blood pressure drops precipitously, and their pulse becomes rapid and weak. If they do not not receive immediate care, they can die.

 

Treating anaphylaxis - the extreme reaction

The treatment for anaphylaxis is epinephrine, which is another name for adrenaline. This is a hormone found naturally in the body, secreted by the adrenal glands. It increases cardiac output and raises glucose levels. It can be synthesized and is administered with an auto-injector, often called an EpiPen. The sufferer or the caregiver jabs the pen into the outer thigh, and a spring pushes the epinephrine out of a syringe and into the muscle where it enters the bloodstream, bringing almost immediate relief by opening the airways and raising blood pressure. People with severe allergies should always have an auto-injector EpiPen with them.

 

Types of allergies

But not every allergic reaction is serious and severe. Many are just chronic and annoying. People can have an allergic reaction to many different things, such as pollen, dust, insect stings, pet dander, drugs, latex, mold, even cockroaches. Food allergies are among the most prevalent. Though more than 170 foods have been reported to cause allergies, eight food allergens are responsible for most reactions: eggs, peanuts, tree nuts, fish, shellfish, wheat, and soy. Milk protein is a common source of allergies, but thorough testing can determine whether you actually have an allergy to the milk protein, or if you have an intolerance to the natural sugar in milk called lactose. Lactose intolerance can be managed with lactose-free milk, milk with added digestive enzymes, or consuming products such as hard cheeses which are naturally low in milk sugar. The most common allergy, however, is hay fever (its technical name is allergic rhinitis); in its seasonal form it is caused by mold spores or pollen from grass, trees, and weeds. In its perennial form it is generally caused by dust mites, pet dander, cockroaches, or mold.

 

How many people have allergies?

It is estimated by the American College of Allergy, Asthma, and Immunology that 40 - 60 million people in the U.S. suffer from allergic rhinitis (hay fever). It is estimated that $26 billion is the annual cost of the diagnosis and treatment of allergies. There are approximately 200,000 visits each year to the ER because of food allergies alone. Almost 10 million adults and 3.8 million children have a food allergy. The Centers for Disease Control and Prevention reports that the prevalence of food allergies in children increased by 50 percent between 1997 and 2011, and between 1997 and 2008 the prevalence of peanut or tree nut allergies appears to have more than tripled in the U.S.

 

 

Asthma and allergy

Allergies seem to be closely allied to asthma, a chronic disease in which the airways become inflamed and narrowed, causing coughing, wheezing, shortness of breath, and tightness in the chest. When severe, it causes decreased activity and even the inability to talk. At its worst it can cause death. An allergic reaction can trigger an asthma attack. When the attack is extreme, the same EpiPen that helps those with severe allergies brings relief to the asthmatic. The American College of Allergy, Asthma, and Immunology estimates that asthma affects more than 24 million people, including more than 6 million children.

 

Why the increasing rates of allergy and asthma?

A number of theories have been proposed to explain why more and more people across the world suffer from allergies and asthma. The hygiene hypothesis suggests that living conditions in the developed world have become too clean. Children are not being exposed to germs that train their immune system to tell the difference between harmless and harmful irritants. Some studies indicate that the increased use of antibiotics changes the bacterial mix in the body, making allergies and asthma more possible. There is research to suggest that the rise of obesity across the world may be a contributing factor, and some experts think that vitamin D deficiency may also be a cause.

 

Others cite environmental changes. We live in a world of synthetics, from the clothes we wear, to the furniture we sit on, to the highly processed foods we eat. There is evidence to suggest that some people react to these "unnatural" substances. In the end, the increase in allergies and asthma may come down to a complex combination of factors, including genetics. Children of parents with allergies and asthma have a higher probability of developing either condition. There is one more cause to consider: climate change. As the average temperature in the U.S. is expected to rise in coming decades, longer growing seasons could further increase pollen and other allergen counts.

 

An evolving world

We live in a world that may be evolving in directions that are harmful to us, our children, and the generations to come. There are some simple things each of us can do to lower our exposure to allergens and keep ourselves healthy (see the article that follows), but it is also important that we be aware of the larger trends in society and the environment, and be ready to take action.