Allergies

An allergy is an exaggerated response by the body's immune system against a normally harmless substance, or allergen. Almost anything can trigger an allergic reaction. Some common allergens are molds, tobacco smoke, certain foods and food additives, insect venom, and chemicals in plants, cosmetics, perfumes, detergents, and soaps.

The first time an allergen enters the body, the immune system reacts by making a defensive antibody called IgE. This initial exposure does not produce symptoms, but the IgE antibodies become attached to other defending parts of the immune system, either basophils, types of white blood cells, or mast cells, which line the airways, intestines, and skin. On a future exposure to the allergen, the programmed antibodies bind to it and signal the mast cells or basophils to produce a barrage of histamines and other substances that cause allergic symptoms.

Because histamines exert the greatest effect on the skin, mucous membranes, eyes, lungs, and gastrointestinal tract, most allergic reactions involve these organs. Depending on the nature of the allergy, symptoms range from the sneezing, runny nose, and itchy, teary eyes of hay fever, to hives, headaches, diarrhea, and the life-threatening systemic collapse of anaphylactic shock.

Doctors do not fully understand why so many people develop allergies. But because they run in families, an inherited predisposition is likely.

Diagnostic Studies and Procedures

In most cases, symptoms of an allergic reaction are self-evident, but finding just what triggers them often requires considerable detective work. Doctors start by asking a number of questions such as: Are the symptoms seasonal? Do other family members have similar symptoms? What seems to trigger them? Do you own any pets?

A physical examination helps to rule out other conditions that have similar symptoms. Allergy tests may then be ordered to pinpoint specific allergens. The most common are skin tests, in which the skin is exposed to small amounts of suspected allergens and then observed for a reaction.

Alternative studies include provocation tests, in which the patient inhales or ingests suspected allergens, and blood tests to look for IgE antibodies.

Exposure to allergens should always be done in a doctor's office or clinic, so that if a severe reaction should occur, it can be treated immediately.

Medical Treatments

Doctors agree that the best approach is to identify and then avoid the suspected allergen. Unfortunately, avoidance is not always possible. In such cases, treatments vary according to severity of symptoms and the types of allergens.

Allergy Medications. Hay fever and other types of pollen allergies are usually treated with drugs that counteract or inhibit histamines. The antihistamines in many nonprescription allergy medications produce drowsiness. (Such antihistamines should never be taken with alcohol, which increases their sedative effect. Also, they may worsen glaucoma, as well as prostate and urinary tract disorders.) There are prescription antihistamines, which do not enter the brain and are nonsedating; examples include terfenadine (Seldane) and astemizole (Hismanal). An alternative prescription medication, chromolyn sodium (Nasalcrom), is an aerosol nasal spray that inhibits the mast ceils from releasing histamine, thus preventing nasal congestion.
In severe cases, steroids may also be prescribed. These work by temporarily blocking the action of white blood cells. They also block prostaglandins, body chemicals that produce inflammation and swelling. Steroids that are used for treating allergies are usually inhaled or applied to the skin.

Other allergy medications work by countering specific symptoms. For example, decongestants relieve nasal stuffiness by constricting the tiny blood vessels in the nose. Topical medications and sprays help to alleviate itching, inflammation, and other skin reactions.

Some types, such as calamine, work by soothing and lubricating the surface of the skin; others, such as benzocaine, are local anesthetics that numb the skin.

Allergy Shots. Also called desensitization or immunotherapy, these are usually reserved for severe allergies that can't be controlled adequately with medication. Periodic injections of increasing amounts of die allergenic extract are given over a long period, usually one to three years. The objective is to build up a natural tolerance to the allergens, thereby reducing symptoms and the need for medications.

Anaphylaxis or Anaphylactic Shock. This must always be treated as a life-threatening emergency. Symptoms that indicate anaphylaxis are facial redness and swelling, widespread itching and hives, difficulty breathing and swallowing, cramps, diarrhea, a sudden drop in blood pressure, and possibly unconsciousness. A previous widespread allergic reaction, such as extensive hives and swelling, sets the stage for a more severe response upon future exposure to that allergen. For example, a person who is hypersensitive to bee venom can suffer shock from just one sting. Treatment consists of injections of epinephrine (adrenaline), followed by observation until the person has recovered.

Anyone who has suffered a hypersensitive reaction or is allergic to penicillin or another antibiotic should wear a Medic-Alert bracelet containing this information. They should also carry an emergency kit that includes a syringe of adrenaline, plus antihistamines. These kits require a doctor's prescription.

Alternative Therapies

Treatment of severe allergies should be overseen by a physician, preferably an allergist. Some alternative therapies, approached with caution, may help to alleviate symptoms, though it is doubtful that any could produce immunity.

Acupuncture and Acupressure. These treatments are aimed at overcoming specific symptoms, such as skin itchiness or a runny nose. In acupuncture, the needles are inserted into the points related to the affected organs.

Acupressure, which also helps to relieve symptoms at the onset of an allergy attack, can be done as a self-care measure. The point to press is in the web of the hand next to the bone that connects with the index finger. Steady pressure should be applied for at least two minutes on each hand, all the while breathing deeply. The effect is said to be similar to an antihistamine.

Herbal Medicine. Chamomile is an ancient herbal remedy for the itchiness and skin inflammation of hives, and it is widely used in skin ointments and lotions. A compress soaked in chamomile tea may also relieve the itching and skin eruptions from poison ivy.

Inhaling steam that contains cloves, bayberry, or eucalyptus can help to ease nasal and sinus congestion.
A word of caution: Some herbal remedies are chemically related to certain allergens and can provoke an allergic reaction; always use them with caution.

Homeopathy. Practitioners sometimes treat specific symptoms, such as giving;' euphrasia or arsenicum for hay fever, or may approach the problem as one component of widespread hypersensitivity.

Meditation. Stress tends to exacerbate allergies and such allergy-related diseases as asthma. Many sufferers find that meditation, yoga, and other relaxation therapies reduce the number and severity of attacks. Although it should not substitute for conventional therapy, meditation may be worth investigating as an additional treatment that can reduce the need for medication.

Naturopathy. Naturopaths have devoted considerable attention to food allergies, and many of their elimination diets are similar to those of more conventional physicians. Their use of dietary supplements to suppress allergies is more questionable, and should be checked with a doctor.

Nutrition Therapy. Counseling by a qualified nutritionist can be very helpful for an individual who has a long list of food allergies. Some allergy diets eliminate entire groups of foods; in such cases, nutrition therapists can suggest supplements or alternatives that will provide a well-balanced diet. They can also pinpoint the potential problems in restaurant dining and teach a patient how to spot the offending ingredients in prepared foods.

Self-Treatment

Anyone who has allergies knows that avoidance is the main line of defense against attacks. For example, seasonal hay fever can be minimized by staying indoors when pollen counts are high and investing in air conditioners for both home and car. If outdoor work is essential, wearing a disposable pollen mask and eye goggles is a good idea.

People with numerous allergies often react to animal dander. If you can't bear to part with a pet, try to keep it outdoors, or at least out of your bedroom. Some animals, such as poodles and rex cats, are said to be less allergenic than others. Recent studies also indicate that female cats are less allergenic than males. Bathing a cat weekly with plain water may reduce its allergy-provoking dander. In any event, before acquiring a pet, you should spend some time with it so you can make sure it does not trigger an allergic reaction.

Following are additional actions that help to reduce exposure to common household allergens:

• Use mold-inhibiting paint rather than wallpaper, which promotes mold growth.
• Consider discarding rugs, deeply upholstered furniture, and other dust-catching furnishings in favor of wood or tile floors and wood furniture.
• Keep the bedroom free of clutter and, if possible, avoid using it as a study or workplace. Objects with crevices or soft, plush surfaces that collect dust should be removed.
• Vacuum mattresses regularly and encase them in airtight plastic covers.
• Buy pillows and comforters that are filled with synthetic fibers rather than kapok or feathers.
• Avoid heavy drapes and Venetian blinds--notorious dust catchers. Use window shades instead. If you do use curtains, launder them frequently.
• Wear a dust mask when vacuuming or dusting. Better still, have someone else do these tasks for you when you are away from the house.
• Keep your bedroom window closed, and use air conditioning, which cleans, cools, and dries the air.
• Don't hang laundry (especially sheets) out to dry -- allergy-provoking pollens and molds may collect on them.
• If your child has allergies, avoid giving him stuffed toys. Many of these contain kapok or other fibers that are highly allergenic.
• Make sure that filters on air conditioners and humidifiers are cleaned or changed regularly.
• Treat damp areas, such as the basement and garage, with antimildew spray and use space heaters for additional drying.

Other Causes of Allergic Symptoms

Chronic sinus infections can cause nasal congestion and other symptoms similar to those of allergies. Itchiness and chronic hives may be caused by drug reactions. Less commonly, liver disorders or lymphatic cancer can produce unexplained itchiness. The rash and itching of psoriasis may also be mistaken for an allergic reaction.