Allergy Basics


Whether it's runny, itchy or stuffed, your nose knows what's bothering it. But do you know what's wrong with your nasal passages? Understanding allergies isn't difficult, but it is the first step toward building a healthy alliance with your nose, eyes, lungs, and sinuses.

In this article, we will look at some of the causes of allergies as well as some of the symptoms of allergies. We will then go into greater detail, exploring topics like why some people are more susceptible to allergies and the different types of common allergies. By the time we're done, you're sure to understand how allergies work!

What Causes Allergies?

Allergies are the result of the immune system's mistaken response to a harmless substance. Normally, the immune system stands guard and defends your body against intruders that can be dangerous to your health, such as viruses and bacteria. When it does its job well, your immune system keeps you from getting sick every time an ill-intentioned germ finds its way into your body.

In some people, however, the immune system has difficulty distinguishing between the good guys (or, at least, the neutral guys) and the bad guys. Like a nervous rookie, it sees danger everywhere and overreacts. A hyperreactive immune system pulls out all the stops for substances that won't do you any actual harm, such as dust, pollen, and animal dander. These innocuous substances are called allergens.

When people who have allergies encounter an allergen, their immune system produces antibodies, called IgE antibodies, that are specific to that substance -- ragweed, for instance, or cat dander.

Thousands of these antibodies bind to the surface of special cells in body tissue called mast cells, which then lie in wait for your next exposure to that specific allergen. While they are waiting, these mast cells absorb many different chemicals from the blood that will aid in the body's defense; they store these chemicals in tiny granules. When you're reexposed to the allergen, the allergen binds to the IgE antibodies on the surface of the mast cells, causing the mast cells to release the chemicals. One of the chemicals, histamine, is probably familiar to you. It is one of the biggest players in the allergic response system and causes many of the reactions, such as runny nose, sneezing, and itchy and watery eyes, that we describe as allergies.

Most anti-allergy medications block the histamine from binding to its receptor and are called antihistamines. The allergic reaction can have both an early and a late phase. Typically the early phase may start within a few minutes of exposure, while the late phase may start several hours after the initial exposure. The early phase is caused by the release of those chemicals stored in the granules in the mast cells. The late phase reaction is caused by other inflammatory cells recruited into the area.

Allergic Symptoms

The body's first line of defense against invaders includes the nose, mouth, eyes, lungs, and stomach. When the immune system reacts to an allergen, these body parts become battlegrounds.

Signs of the battle can include one or more of the following: runny nose; sneezing; watery, swollen, or red eyes; nasal congestion; sinus inflammation and pressure; hives; rashes; itchy eyes; itchy nose; wheezing; shortness of breath; a tight feeling in the chest; difficulty breathing; coughing; diarrhea; nausea; headache; fatigue; and a general feeling of misery.

It's ironic that the immune system, designed to protect you from illness, produces symptoms that make you feel sick when it overreacts to mundane substances. But that's the nature of the allergic response. The symptoms are the unfortunate result of the immune system's overperformance. It's a perfect example of the old saying that sometimes the cure is worse than the disease.

In the next section, we will answer a question you may have asked before: What makes certain people susceptible to allergies while others get away with nary a sneeze?

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

What Makes Some People Susceptible to Allergies?

Why some people are allergic to certain things while others are not can be a difficult topic to understand. For example, a dog can jump into your lap and, just like that, you will start to sneeze and your eyes will drip. All of this will force you to toss Fido aside in search of a tissue box. Meanwhile, your friend or neighbor experiences none of the above effects.

Why is this? There are three main reasons: inherited genes, environment and age.

It's in the Genes

Allergies can often be blamed on mom and dad. The tendency to become allergic is inherited, and the chances that you also will be allergic increase from about 50 percent when one parent is allergic to 75 to 80 percent when both parents have allergies.

Tell your friends you're "atopic," meaning that you have inherited the tendency to have an allergy.

(And hope that none of your friends know Greek, as "atopic" derives from the Greek word for "strange.")

But you needn't feel strange...or alone. The American College of Allergy, Asthma and Immunology (ACAAI) estimates that as many as 50 million Americans suffer with asthma, hay fever, or other allergy-related conditions.

So, the family genes are stacked against you. Does this mean instant sniffles? Not always. Don't forget, even if you have a 60 percent chance of developing allergies, you also have a 40 percent chance of not developing them. That's why Fido turns your nose and eyes into streams while your brother is pretty much dry. In the genetic roll of dice, he came out the winner.

Environment Counts ...

There's more to developing allergies than heredity. What you become allergic to is based on when and how much you're exposed to a substance and how much of it you're exposed to.

For example, say you have a tendency to be allergic to mold spores. You may have no allergy symptoms when you're living alone in your spic 'n' span apartment, but when a roommate moves in, bringing along a jungle of house-plants, an old mattress, and a humidifier (to keep her skin moist) you soon become a symphony of sneezes and snorts. What happened? You had endured a certain amount of exposure to mold spores without a problem, but once the scales were tipped by the onslaught of your roommate's mold-bearing stuff, your immune system kicked into high gear.

... As Does Age

How old you are when you're exposed is critical, and viruses may also play a role. Recent studies show that heavy exposure early in life -- before age 2 -- may be protective against animal allergies and asthma.

Now that we've discovered the source of allergies and what makes certain people susceptible to them, it's time to look at specific types of allergies. First up is the most common type of allergy -- allergic rhinitis.

Allergic Rhinitis: Grass Pollen

The air is full of flying things. Luckily they're microscopic or you'd have to wear a suit of armor even in your own home. Unless you live in a sanitized glass bubble, it's impossible to completely avoid airborne allergens, such as pollen, dust mites, and pet dander. These identifiable flying objects cause allergic rhinitis, which simply means an inflammation of the nasal membranes. If you've heard of hay fever (and that includes everyone who has turned on a television or radio in the spring or summer, since there are so many commercials for antihistamines), then you know about allergic rhinitis: It's that drippy nose, itchy eyes and throat, and sneezing that's so familiar during pollen season.

While pollen is one of the most common triggers of allergic rhinitis, it is not the only one. Mold spores; dust-mite droppings; cockroach body parts; and animal dander can also prompt an allergic reaction. You can be allergic to only one or to several of these airborne particles.

The next few sections will help you understand the pollens, spores and pets that cause allergic rhinitis.

Allergic Rhinitis: Love is in the Air..

Birds do it, bees do it, and so do plants. They all reproduce. Pollen grains, the stuff that makes you sneeze, are simply the microscopic male reproductive cells released by trees, grasses, and weeds. A pollen grain, similar to the male sperm, contains half the genetic material needed for reproduction. Pollination occurs when pollen grains are released by one plant and carried by the wind to another similar plant in order to fertilize it. (Large pollen is also carried via birds and insects, but these don't cause you to sneeze.)

 

Love in the air elicits a romantic response from plant life, but for some forms of human life (i.e., allergy sufferers) it guarantees an allergic response. The terrible trio of tree pollens, grass pollens, and weed pollens causes misery for allergy sufferers, especially from spring to fall. Unlike the pollens from flowers and shrubs, this trio releases pollens that are light, numerous, and easily transported by the breeze.

You can get an idea of the kind of pollen that most troubles you simply by observing when your symptoms start and when they wane. Tree pollens, for instance, herald the beginning of the allergy season. Although pollen seasons vary by geographic region, those stately, shade-producing trees we love -- box elder, chestnut, ash, walnut, cottonwood, oak, elm, maple, willow, cedar, sycamore, and more -- typically send out showers of pollen from March through May. (In Texas, however, cedar pollen season is January!) Thankfully for aching noses and irritated lungs, tree pollination season is short-lived.

Grass Pollens

Just when you thought it was safe to venture outside, out pop grass pollens. More common than tree pollens, grass pollens generally reach their peak from mid-May to mid-July, although the timing varies by geographical region. In California and Florida, for instance, grass pollen season is from February through October. Grass pollens are larger than tree pollens (often you can see them in the air), and they affect the nose and eyes most drastically. There's no escape, as the wind transports grass pollens to all ends of the earth. With 9,000 grass species worldwide, it's hard to name all, but popular pollinators in North America include barnyard grass, Bermuda grass (in southern areas), bluegrass varieties, corn, fescue, ryegrass (cultivated lawn grass), cultivated wheat, and wheat grass.

In the next section, we will talk about a different kind of pollen that can affect you just as much as grass pollen. The offender? Weed pollen. 

Allergic Rhinitis: Weed Pollen

Summer is half over by the time grass pollens are finished doing their job. That's when weed pollens, which have waited patiently, spring forth. Those pesky plants that, along with cockroaches, will inherit the earth someday are ready to take over pollen production from midsummer to mid-fall. This section looks at the ways that weed pollens can cause allergy havoc for millions of Americans.

Ragweed Is King

When it comes to weed allergies, ragweed is the star. Its pollen is one of the most potent. Only a few ragweed pollen grains are needed to produce hay fever, which is bad news considering that one ragweed plant can produce one billion pollen grains in a season. This demon plant knows no boundaries and in some places can grow 12 feet or higher. Ragweed pollens love to book one-way tickets out of town: Ragweed pollen has been found 400 miles out to sea and two miles up in space.

While there are few places to hide, ragweed isn't fond of areas in upper New England or the southern tip of Florida. The West Coast has western ragweed, which is not as bad as giant ragweed but still causes allergies. While the Rocky Mountain states don't have ragweed, they do have other weed pollens.

Other Types of Weeds

Some weeds are prolific pollinators. Take dock weed for example, which comes in several varieties -- bitter, green, white, and yellow; it pollinates from April all the way to December.

Other weeds to watch out for include aster, cattail, clover, dandelion, fireweed, mugwort, nettle, pigweed, California poppy, rabbit brush, sagebrush, and Russian thistle. Along with the nuisance weeds, some crop weeds, such as alfalfa, hemp, hops, sweet clover, and sunflower, produce pollens, too.

Monitoring Weed Pollen

Allergists and meteorologists help you stay on top of pollen allergies by constantly assessing and reporting on the amount of pollen in the atmosphere. During pollen season, these experts take daily pollen counts, which measure the number of pollen grains in one cubic meter of air during a 24-hour period. Pollen is collected with a plastic rod or similar object that is covered in a greasy, sticky substance. The rod rotates or spins continuously, collecting pollen specimens that are then examined under a microscope and counted. Local wind currents, rainfall, and humidity sometimes limit the accuracy of the readings.

Many newspapers list local pollen counts on the weather page and some newscasts announce pollen counts during the weather report. Always remember that the pollen count you hear on the news is 24 to 48 hours old and counts can change quickly depending on weather conditions. Pollen counts are worse on clear, windy days and generally improve on rainy days or after the first light frost. Make note of the weather conditions the day prior (when the pollen count was taken) before drawing any conclusions about present-day pollen conditions.

Where to Find Pollen Counts

If you don't see the pollen count in the paper or on television, you can get pollen counts by going to the following site(s) on the Internet:

Now that we've covered grass and weed pollens, it's time to take a look at two more causes of allergic rhinitis. The next section will cover the evils of mold spores and house dust mites.

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

Allergic Rhinitis: Mold Spores

As if pollens aren't enough, there are fungal spores, commonly known as mold spores, floating around in the air you breathe. Spores differ from pollen in how they reproduce, but they are spread the same way. As the season becomes warmer (summer to early fall), mold spores hit the air currents. Some mold spores prefer to ride the dry winds, while others need high humidity and condensation to get off the ground. Thankfully, only a few dozen out of the hundreds of molds trigger allergic reactions. Those that do, however, do it well, infiltrating the nose and lungs and triggering hay fever and asthma  flare-ups.

(Don't) Shake It Up

Mold spores love moisture and often grow on the ground or on decaying vegetation, so victims usually inhale them while "stirring things up" during activities such as mowing the lawn, raking leaves, and cleaning the basement. When you stir things up, molds become airborne. But molds (and pollens) can also enter your life through an open window, carried in with the breeze, which you then breathe.

Indoors, mold will set up housekeeping if you have the ideal environment for them to thrive and reproduce. Prime mold real estate includes dirty laundry hampers, old newspaper piles, carpeting, fireplace logs, houseplant soil, foam rubber mattresses and pillows, bathtubs, bathrooms, and dark, damp basements. Water leaks from pipes or windows speed the development of mold, especially if the water gets on carpeting. Humidifiers and vaporizers are also a major source of indoor mold. Need we mention that mold spores love traveling, too? Air-conditioning vents (home and car, alike) have the best seating.

If you are highly allergic to mold spores but not to pollens, moving to a drier, high-altitude area may help ease your allergies.

Allergic Rhinitis: Dust Mites

House dust mites are members of the arachnid family, eight-legged creatures that include spiders. These microscopic insects are harmless, but their droppings contain proteins to which many people are highly allergic. In fact, about 80 percent of children with asthma are sensitive to dust mites, as is about 10 percent of the population as a whole.

 

Dust mites love to feast on protein products such as human and animal skin flakes (dead flakes, fortunately). Luckily, the human eye can't see this mite-ty picnic, unless it's held underneath a microscope. Huge gatherings (a typical used mattress may have anywhere from 100,000 to 10 million mites inside) will dine all day and night in bedding, carpeting, and furniture, especially when such hangouts are toasty warm and frequented by humans. Dust mites don't need drinks to wash down their feast. They absorb moisture from the humid air through special glands.

These ugly creatures don't fly, but their fecal pellets can become airborne, and that's the problem for the allergy prone. When you ruffle your blankets, fluff your pillow, sit on the couch, or walk across your carpet, millions of microscopic fecal pellets are propelled into the air and onto the mucous membranes of the nose, eyes, and airway linings. Voila: an allergic reaction! And it doesn't help to hold your breath. Mite poop remains airborne for 20 to 30 minutes before settling.

Dust mites are everywhere in the United States except the desert and locations higher than 5,500 feet. They thrive at room temperature with humidity higher than 50 percent. In North America, the Gulf Coast region, especially sunny, humid Florida, and the mild and damp Pacific Northwest are favorite spots. Around the world, dust mites flourish in northern Europe, Venezuela, Brazil, parts of Australia, New Zealand, Japan, and the United Kingdom.

In the next section, we will conclude our look at allergic rhinitis with an overview of how cockroaches and pets can trigger allergic symptoms.

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

Allergic Rhinitis: Cockroaches

Allergies can also be caused the little critters scurrying around your house. Whether a cat or cockroach, they could be contributing to your allergic reactions.

Cockroaches

Dust mites and their droppings may be horrible to think about, but at least you can't see them. Cockroaches, on the other hand, are visible. Although they scuttle away when the kitchen light comes on, they leave behind their droppings in the form of little pellets. The feces contain a digestive enzyme thought to be an allergen. If that's not enough, dead roach body parts, themselves known allergens, adhere to dust particles. These become airborne and cause an allergic reaction when they enter the nose, eyes, and lungs. Extermination can actually increase the problem because there will be more body parts in the dust. For roach control, it's best to use traps, such as the Roach Motel.

Like dust mites, cockroaches adore a warm, humid environment. Not all cockroaches live indoors, but those who enter homes to forage for food (and reproduce) live in every room. But it's the kitchen that continues to be their favorite snacking ground for obvious reasons.

Allergic Rhinitis: Pet allergies

While cats, dogs, and other pets are much more cute and cuddly than dust mites and cockroaches, they also produce allergens, most notably those found in their dander (flaky, dead skin cells) and saliva. Cats, with their predilection for primping, spread the allergen from their saliva to their fur.

Once dried, it flakes off and becomes airborne. Cat allergen particles are small and can stay airborne for several hours. Not only do they love air travel, but these allergens will happily travel overland.

Their sticky nature helps them cling to clothing, transporting them to homes and offices where a cat has never set down a paw. The urine of female cats and rodents is also allergenic. Allergies to dogs are less common and typically less intense than those to cats, but dog saliva and dander contain allergens, too. Although dogs don't groom as readily as cats, many are happy to lick their human companions, often provoking a reaction.

Birds, gerbils, mice, guinea pigs, rats, rabbits, and horses can all cause allergic reactions in sensitive individuals. However, amphibians and reptiles aren't allergenic.

And fish seem to be relatively free of allergens, as they don't shed in our living room. However, be wary of mold spores growing around the fish tank.

Many airborne substances can trigger allergic rhinitis, including mold spores, dust-mite droppings, cockroach leavings, and animal dander. Now that you have a solid understanding of this allergy type, it's time to look at a few other types of allergies. In the next section we will review allergic asthma.

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

Allergic Asthma

Asthma is a respiratory disease that affects the lungs and is intricately linked with allergies. A tendency towards asthma often is inherited. Although we know a lot about asthma and more than 20 million Americans have this disease, we do not know what causes it. This section will explore what we know about allergic asthma.

What Exacerbates Allergic Asthma?

Triggers of allergic asthma include allergens such as mold, pollen, dust-mite and cockroach leavings, and animal dander. Other triggers include an assortment of irritants such as cigarette smoke and stimuli such as cold weather, infections, and exercise.

Being a worrywart or the fearful type may also trigger asthma attacks or make an attack more severe. Emotional stress and bodily reactions are tied together in a bond that is, fortunately, breakable through such means as relaxation and exercise, stress management, and proper nutrition. Other asthma triggers capable of causing (or worsening) asthma symptoms include viral infections, drug allergies, and even positive emotions, such as excitement and laughter.

When asthmatics encounter a trigger, their airways become inflamed and swollen and increase the production of mucus, all of which reduce the supply of air. Wheezing, that whistling sound from the chest that can be heard on exhalation, is the most recognizable asthma symptom, a result of a constricted airway. However, some asthmatics never wheeze. Other symptoms may include coughing, shortness of breath, tightening of the chest, and difficulty breathing.

Symptoms of Allergic Asthma

Asthma symptoms range from mild to severe and may occur occasionally or on a daily basis. Asthma typically starts during childhood, but adults can develop it. Exposure to irritants, such as cigarette smoke, at an early age increases the chances of developing asthma.

An Asthma Attack

Imagine wearing a Victorian corset around your chest that someone keeps pulling tighter and tighter. Such a feeling is a reality to modern-day asthmatics...and they don't even wear corsets. When an asthmatic encounters a trigger, the body reacts by flooding the airways with mucus and causing the inner lining of the bronchi to swell and the airway muscles to contract.

Asthmatics, including children, should identify and avoid triggers of an attack, know signs of an impending attack, and be prepared with prescribed medications. Asthmatics should also alert friends, family, and associates to the classic symptoms of an attack: difficulty breathing, difficulty speaking and walking, hyperventilating, a fast pulse, and a blue or gray skin tone, particularly around the lips (from lack of oxygen). Most importantly, asthmatics and others should know that an asthma attack is a medical emergency and should be treated accordingly.

Does your skin itch whenever you apply a certain lotion or cream? We'll find out the cause in the next section, which reviews skin allergies.

 

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

Skin Allergies

The skin is your largest organ and an important defender against invaders. It is constantly bombarded and usually fends off trouble quite successfully. Sometimes, however, an allergen gets the best of your skin, causing a reaction. This section will explore skin allergies and the reactions they cause.

Skin Allergy Symptoms

Symptoms can include a rash or hives, or swelling, itching, and cracking of the skin. Our hands, arms, neck, and face come in contact with so many substances every day that they are the most common sites for an allergic skin reaction, but no part of your anatomy is immune. A skin reaction that is the result of contact with an allergen is called allergic contact dermatitis. (By contrast, a skin reaction caused by contact with a substance that is harsh or caustic is called irritant contact dermatitis and does not involve allergies or the immune system.)

What Causes Contact Dermatitis?

Potential allergens exist everywhere. Many can be rounded up in the bathroom cabinet: nickel/chrome in jewelry and snaps; latex found in condoms, rubber gloves, bandages, and rubber bands; chemicals in cosmetics, toiletries, and perfumes; hair products, including hair dye; and laundry detergent and fabric softeners. The great outdoors hosts such potential villains as poison oak, poison sumac, and poison ivy.

Identifying the exact cause of allergic contact dermatitis can be difficult because your skin comes in contact with hundreds of suspects a day and first reactions may occur hours or days after the initial contact. In some cases, a reaction doesn't occur until weeks or months of prolonged use. Luckily, contact dermatitis isn't named contact for nothing. Many allergens leave a trail to follow. The location of the rash, hives, or itch will help you to put the suspects in a lineup.

For example, let's say your ears itch. What comes in contact with them? Earplugs, headphones, earrings, perfumes, hair products, and lotions might be major suspects.

How about a rash that develops under your arms? The possible causes: lotion, deodorant/antiperspirant, elastic straps in clothes, a bra's underwire, new fabrics, etc. Like so much in the allergy world, a little observation can go a long way toward discovering what is irritating you.

Pinpointing and avoiding contact with the allergen is the primary treatment for allergic contact dermatitis. However, if the rash spreads or if you develop hives or experience uncontrollable itching and the skin becomes red, tender, and damaged, see your physician.

Exploring Eczema

 

Eczema, also called atopic dermatitis, is a kind of skin allergy, but it is of mysterious origin.

Symptoms include red, itchy, dry, scaly patches most frequently on the face, arms, legs, and scalp. Infants and children are particularly susceptible to eczema, but the vast majority of children who have eczema outgrow it. It's clear that there's a connection between eczema and allergies, since 70 percent of those who have this skin condition have a family history of allergies or asthma. And one-third of those with eczema eventually will develop allergic rhinitis or asthma.

There is no cure for eczema. The best preventive measures are to moistureize your skin so it doesn't dry out and to pinpoint and avoid substances that seem to irritate your skin or trigger the rash. Additionally, topical medications containing steroids can help control itching, as can oral antihistamines.

Your skin is always being exposed to potential allergens. Allergic contact dermatitis and eczema are two different types of skin allergies. Identifying and treating them is a matter of being informed and knowledgeable.

Had a bad reaction to a wedge of cheese? A glass of milk? In the next section, we will look at food allergies and how to deal with them.

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

Food Allergies

There are two types of reactions to food. One is the result of an actual allergy while the other is a result of an intolerance. Food intolerance is actually the more common of the two, but food allergies are the more serious. In this section, we will explore the symptoms and causes of food allergies as well as how to tell a food allergy from a food intolerance.

What Is a Food Allergy?

A food allergy is a hypersensitivity or abnormal response by the immune system to a certain food.

It's a sensitivity that develops the same way as allergies to pollen or mold. First your body already needs to have encountered the allergen (in this case, a food) in order to have developed antibodies to it. That's why you can have eaten a peanut once and not have had a reaction to it. It's only the next time you eat a peanut that your body reacts as the antibodies to peanuts now rally themselves for a fight.

Food Allergy Symptoms

The symptoms of an allergic reaction to food range from tingling lips and tongue to abdominal cramps to difficulty breathing and, most seriously, shock. The site of the reaction and its severity can vary. When two or more organ systems are involved or if there is wheezing, the reaction is considered severe. Reactions may get progressively worse with subsequent exposures. Just because a person has had only mild reactions to an allergic food does not mean that the next reaction will not be serious and potentially fatal.

Food Allergies in Children

Like other kinds of allergies, the tendency to have food allergies -- but not the specific allergy -- is inherited. And certain foods, including milk, eggs, wheat, peanuts, fish, shellfish, and tree nuts, are the most frequent troublemakers. Children often have more food allergies than adults, especially to cow's milk and peanuts. Many food allergies in infants are outgrown by age four. Reactions to shellfish, fish, and tree nuts are more common in adults.

Which Foods Are Responsible for Your Allergies?

It can be tricky identifying what food is causing your symptoms. It's usually obvious, but it may not be, especially if you're reacting to a spice. Less obvious reactions require a bit of detective work.

The answers to the following questions can be revealing:

  • What was the timing of the reaction?
  • Does the reaction happen after eating a certain food or meal?
  • Was the food fully cooked?
  • What else was eaten (including spices, condiments, beverages...)?
  • Did anyone else experience symptoms?

Food IntolerancesFood intolerance is a chemical reaction that doesn't involve the immune system. Classic examples include lactose intolerance, irritable bowel syndrome, and heartburn. Lactase deficiency ranks as one of the most common types of food intolerance. If your body doesn't have enough of the enzyme lactase, you can't properly digest lactose, the sugar found naturally in milk and milk products. Symptoms of lactose intolerance include bloating, abdominal cramps, and diarrhea.Taste enhancers, fancy food colorings, and preservatives are also on the list of food intolerance causes. Perhaps the best-known example is monosodium glutamate (MSG), a flavor enhancer commonly used in restaurants and processed foods. When MSG is ingested in large amounts, sensitive individuals may experience flushing, headaches, and chest pain. Sulfites are another common cause of food intolerance. Sulfites are substances that occur naturally in some foods (such as wine) and are added in others to preserve texture and prevent mold. Asthmatics risk an attack if the sulfite-containing food they consume gives off sulfur dioxide. This gas irritates the lungs, causing spasms and constriction of the airways.Now that we've covered food and skin allergies, it's time to look at other factors that can contribute to allergies. In the next section, we will explain how drugs and even your workplace can cause allergic reactions.

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.

Drug and Workplace Allergies

Although people experience all kinds of reactions to medications, these are usually side effects of the drug (which you'll usually find listed and described in the patient information insert) rather than allergic reactions.

An unexpected allergic reaction to a drug is rare, but the symptoms can be severe, ranging from skin rashes and hives to fever and anaphylaxis, a severe and life-threatening reaction that includes swelling of the mouth and tongue, rapid heartbeat, difficulty breathing, a drastic drop in blood pressure, unconsciousness, and even death. This section will help you to better understand the nature of drug allergies before discussing the impact of environment.

Which Drugs Can Cause Allergies?

Drugs infamous for causing allergic reactions are some of the same drugs made famous for saving countless lives, most notably penicillin and sulfa drugs. Other drugs known to cause allergic reactions include barbiturates (rare), anticonvulsants, Novocain and other local anesthetics (very rare), and insulin, especially insulin derived from animal sources. Aspirin and aspirinlike drugs are also a common cause of allergic reactions and are known to trigger asthma attacks, especially in children.

Risk for Allergic Reaction

Are you at risk for having an allergic reaction to a drug? The following will help you decide:

  • Family history. Is anyone in your family allergic to any drugs? If so, you may have inherited the allergic tendency.
  • How long have you taken a drug? You won't experience an allergic reaction the first time you take a drug; you need to develop antibodies to it, just as you do with other types of allergies. Therefore, the longer or more frequently you take a drug, the greater the chance of developing an allergy.
  • How was the drug administered? Topical medications and injected medications are more likely to cause a reaction than those taken orally.
  • Your age. Adults are more likely to have an allergic reaction to medications than children.
  • Your dosage. The higher the dose, the more likely an allergic reaction.

The Office as IncubatorIn an effort to conserve energy, modern office buildings are built as tight as tombs, often with inadequate fresh air circulation. Allergens and irritants fill the air with no place to go. Carpet-cleaning solvents leave irritating chemical residues. Fiberglass or other particles in the air bother eyes. Mold spores, freely circulating in the moist, continually running air-conditioning units, annoy sensitive noses. And, if co-workers have pets at home, there might even be animal dander floating in the atmosphere.

Enclosed office spaces aren't the only workplace susceptible to environmental problems. Many professionals and trades people, because of the chemicals they work with, also are prone to environmental allergies, whether they work indoors or out.

Professions that are susceptible to allergy include:

  • Industrial workers handling paints, chemicals, solvents, and plastics
  • Beauticians, who constantly work with hair dyes, hair perms, and nail polish and polish removers
  • Farm workers dealing with fertilizers and pesticides
  • Photocopier technicians working in enclosed offices with machines and papers that emit potentially harmful gases.
  • Medical professionals, who can become sensitized to latex (in surgical gloves)
  • Bakers, who can suffer from flour or wheat allergies, dubbed "baker's rhinitis" in honor of the most common victims.

Are Your Allergies Work-Related?Some detective work might offer clues about whether or not you're allergic to a work environment.

Ask yourself these questions:

  • When do the symptoms start and when do they stop?
  • Do symptoms start in a certain area (the copier room, for example) or when I am performing a specific job?
  • What are the symptoms like on weekends or on vacation? Bring your observations (not conclusions) to your doctor.

We will conclude our look at how allergies work with an overview of allergic reactions to insect bites and stings in the next section. This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider. The brand name products mentioned in this publication are trademarks or service marks of their respective companies. The mention of any product in this publication does not constitute an endorsement by the respective proprietors of Publications International, Ltd. or HowStuffWorks.com, nor does it constitute an endorsement by any of these companies that their products should be used in the manner described in this publication.

Allergic Reactions to Insect Bites and Stings

If you've ever been the target of a bee or yellow jacket, you know there's often more to their sting than the initial pain. The body responds with swelling, redness at the site, and itching. Applying ice and a disinfectant, however, usually helps ease swelling and suffering.

For five percent of the population, though, an encounter with a stinger or a bite can be more than uncomfortable -- it can be life threatening because they're allergic to the insect's venom. Symptoms of an allergic reaction range from hives, itching, or swelling throughout the body to tightness and swelling of the throat, breathing difficulty, a sudden drop in blood pressure, dizziness, unconsciousness, and cardiac arrest. The reaction generally occurs within minutes of being stung.

If you're allergic (or suspect you're allergic) to stings or bites, be sure to let other people know and be prepared to self-inject epinephrine. Your doctor can provide you with an emergency injector to keep on hand.

Avoiding Bites and Stings

Avoiding yellow jackets, hornets, wasps, bees, and fire ants is better than treating yourself once you're stung or bitten. Here are some simple preventative measures:

  • Don't walk barefoot in the grass, which is a favorite nesting and resting ground for stinging insects.
  • Stay clear of nests or hives. You're viewed as a big, two-legged threat and will be attacked. Have a professional pest-removal company remove any nests in the vicinity.
  • Never place your hands in dark corners, into holes, or underneath objects without looking first.
  • Cover food when dining outdoors, and do not drink from an open soda can. Stinging insects love sweet soft drinks as much as you do and sometimes go inside while they're drinking. Always pour your drink into a clear container.
  • Wear long-sleeved shirts and pants to reduce skin exposure.
  • Don't dry your laundry outside. Flying, stinging insects might get caught in the laundry and be brought inside.
  • If a stinging, flying insect uses you as a landing pad, don't flail and scream. Remain calm and gently brush off the intruder, then quickly exit the scene.
  • Lastly, don't look like a flower. Save your bright, floral shirts for the indoors. And, since we're on the floral theme, avoid smelling like one, too. Perfumes, lotions, and hairspray smell sweet and attract stinging insects.

If you think you're allergic to insect venom stings, consult your doctor. Venom immunotherapy, in which gradual doses of venom are administered to stimulate the immune system to become resistant to future allergic reactions, may be an option. The immunotherapy can dramatically decrease your chance of anaphylaxis from 50 percent to less than 0.57 percent.Over the past few sections of this article, we've talked all about allergies and their sources, causes and solutions. The most important part of fighting allergies is compiling a good working knowledge of what you're battling against. Once you understand that an allergy is nothing but a reaction to an otherwise harmless substance, you can learn how to avoid your allergen or what to do if you should come in contact with it.

©Publications International, Ltd. This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider. The brand name products mentioned in this publication are trademarks or service marks of their respective companies. The mention of any product in this publication does not constitute an endorsement by the respective proprietors of Publications International, Ltd. or HowStuffWorks.com, nor does it constitute an endorsement by any of these companies that their products should be used in the manner described in this publication.