Allergy Primer

What are the underlying causes of allergies?

Allergies are curious phenomena. They make you react to harmless substances like pollen, dust, mold, food and cat fur that ordinarily don’t bother people. These substances cannot hurt us like infectious diseases or animal bites, so your body need not protect against them. Yet it tries to anyway, with potentially harmful signs of disease when you have allergies. What causes this situation to occur?

An epidemic of allergies

Certain kinds of allergies have increased dramatically in developed nations over the last century. At present hay fever afflicts one in five people. The frequency of asthma has increased more than 10-fold in the past 40 years. An estimated 60 million people suffer from all types of allergies in the U.S.

While not fully understood, several factors lurk behind the growing allergy epidemic. These include improved sanitation, fewer infections from worms and parasites, greater efficiency of home heating and ventilation, decreased levels of physical activity, and increased consumption of processed foods. Some of these changes have brought progress in terms of fewer deaths from infectious disease. As a whole, however, they have ushered in a higher frequency of hay fever and asthma.

The most popular explanation for the rise in allergies is called the hygiene hypothesis. It argues that better hygiene leads to increased allergic disease. Exposure to germs in early life, the hypothesis goes, influences the normal development and maturation of your immune system. It does this partly by affecting the amounts and types of friendly bacteria living in your intestines. Scientists have discovered the vital role these beneficial bacteria play in regulating your immune system. Not having enough good gut bacteria, or having too many bad ones, can throw your entire body’s immunity out of whack. Even a small imbalance can set up a situation that encourages the formation of allergies.

While scientists suspect the growing allergy epidemic starts with reduced germ exposure in childhood, proof of the hygiene hypothesis still remains to be seen. In the meantime, there exists a huge need for more research about the underlying causes of allergies.

Types of allergic conditions

Hay fever, eczema and asthma are the leading allergic disorders, and all three frequently occur in the same people. The manifestations of allergies are varied, however, and may include the following conditions.

Hay fever. In this condition, your body’s response to allergenic substances causes chronic inflammation of the mucous membranes inside your nose. Subsequent exposure to pollens, dust, dander or other allergens can trigger symptoms such as sneezing, itching, nasal congestion, runny nose, post-nasal drip, cough, and tearing eyes. Other signs include fatigue, irritability, difficulty concentrating, and poor appetite.

Eczema. Also known as atopic dermatitis, the allergic condition consists of itching and inflammation of your skin. Rashes most commonly appear on your hands and feet, front of your arms, and behind your knees.

Allergic asthma. Asthma is a chronic inflammatory lung condition in which your airways constrict and dilate and produce extra mucus. The characteristic symptoms consist of coughing, chest tightness, shortness of breath and wheezing.

Eye allergies. The tell-tale signs of itchy, watery, and red or swollen eyes can occur acutely, seasonally or year-round. Eye allergies can happen alone or be part of hay fever.

Food allergies. Allergies can arise when your body’s immune system reacts abnormally to constituents in food. The symptoms of food allergy may affect many different areas of your body.

For more information: Allergy Guide: Alternative & Conventional Solutions by Elizabeth Smoots, MD (found online wherever books are sold).

This newsletter is for educational purposes only. It is not intended as a substitute for medical advice or treatment; before adhering to any recommendations in this newsletter consult your healthcare provider.