What should I know about Allergies?
If you have an allergy, your body’s immune system has been programmed to treat a particular substance in food or the environment as an enemy. Defending us against harmful substances is part of the immune system’s job. With allergies, the immune system reacts to a substance that, for the non-allergic person, is completely harmless. Hay fever, for example, is an allergic reaction to pollen. Why do some people have hay fever, while everyone else can breathe in pollen particles with no problem? Because the immune system in the hay fever sufferer sets an allergic reaction in response to pollen molecules that come in contact with sinus passages.
The specific substances that cause allergic reactions are called “allergens.” Composed largely of protein, allergens can be food ingredients, chemicals, or environmental substances such as pollen, dust mites, and animal dander. (Another word for allergen is “antigen.”)
The allergic reaction, also known as a “hypersensitive” reaction, triggers the release of chemicals into the blood stream, chiefly histamine. Normally stored away inside cells that are part of the immune system, these chemicals produce the various symptoms and discomforts of allergies. These symptoms ranges in severity from mild to life-threatening.
The immune system has two basic functions. First our immune defenses recognize and destroy bacteria, viruses, parasites, and any other foreign invaders. Second, the immune system works to minimize the damage to tissues and organs from the invasion.
The immune system consists of several branches, each with its own protective functions. White blood cells known as “B cells” (B-lymphocytes) play a key role. B cells coordinate with other cells in the blood called “plasma cells” to produce a series of large proteins known as immunoglobulins. Immunoglobulins are antibodies capable of recognizing, destroying, and positioning antigens for removal from the body.
The immune system has five different classes of antibodies: IgE, IgA, IgG, IgM, and IgD. Each class is designed to go after certain category of antigens. Antibodies are “antigen-specific,” which is to say that an individual antibody is programmed to recognize and attack a specific foreign invader. For example, antibodies against viruses are assigned to one virus only. When the body becomes infected by a flu virus, a specific antibody is created to recognize and destroy the virus. This is how we become immune to future infections by the same virus.
IgE (immunoglobulin E) is the antibody class that is largely responsible for allergic reactions. IgE triggers a special type of immune cell called the “Mast cell” to release histamine and other potent chemicals into the blood stream. The first line of our immune defense network, Mast cells act like sentries at the places where we interface with the outside world: the intestinal tract, the sinuses, the lungs, and the skin. Mast cells come equipped with IgE antibodies positioned on their surfaces. Before joining forces with Mast cells, IgE antibodies are pre-set to recognize specific antigens. This pre-programming takes place through the activity of T cells and B cells, which are other key players in the immune system.
When an antigen comes in contact with IgE antibodies, an “antigen-antibody” complex is formed. This complex signals the Mast cell to open up storage granules inside the cell that contain histamine and a host of other potent chemicals. This process is called “degranulation.” Once in the bloodstream, these substances produce allergic reactions in the skin, the respiratory tract, and the gastrointestinal tract.
Other antibodies such as IgG and IgM are being implicated in food intolerance reactions, causing a whole different set of symptoms, which could include neuropathy, intestinal symptoms, and problems with energy production. (1)
No one knows exactly why some people develop allergies. One theory links allergic reactions to parasite infection. (2) This theory proposes that the human immune system has developed a high sensitivity to parasites. When a parasite infects the body, according to the theory, production of white blood cells increases, along with substances involved in allergies that cause inflammation. In developed countries, where parasitic infestation is relatively low, allergies are more common than in less developed countries. It is thought that when the immune system is fighting parasitic infections, it does not have the resources to defend against less threatening agents. Another theory is that people with poor intestinal health may be more prone to allergies.
Genetics appear to play a significant role in allergies. Some people inherit the tendency to make more IgE antibodies in the bodies than normal. Children whose parents both have allergies are twice as likely to develop allergies themselves. (3)
Repeated exposure to allergens and environmental pollutants may stimulate the production of IgE antibodies. (4) The prevalence of allergy-related conditions, such as asthma and eczema, has risen steadily since the 1960’s, perhaps in conjunction with increasing levels of pollutants. (5) One factor in the development of allergic reactions is the absent or weak response of the T suppressor cells. In non-allergic individuals, suppressor T cells keep the antibody response under control. In allergy-prone individuals, this function of the T cells is not as effective.
World Health Organization, 2005.
- Allergic rhinoconjunctivitis affects more than 115 million people worldwide
- 30%-50% of people are genetically predisposed to develop Immunoglobulin E antibody (IgE) to common environmental allergens. The term for this predisposition is atopy.
Malaysian Society of Allergy and Immunology, 2006.
- One out of three Malaysians is allergic to something.
- 50% of Malaysians will be allergic by the year 2020.
American Academy of Allergy, Asthma and Immunology in San Diego, 1999.
50 million people suffer from allergies. Of these, 1/6 have allergic asthma. 6 million have non allergic asthma caused by exercise, chemical pollution, and smoking.
Centers for Disease Control, 2004.
12% of U.S. children under 18 years of age suffered from respiratory allergies in the past 12 months. Children living in the South (15%) were more likely to have respiratory allergies than those living in the Midwest (11%), Northeast (10%), or West (8%).
Signs and Symptoms
The following list does not insure the presence of this health condition. Please see the text and your healthcare professional for more information.
Allergic reactions are classified into four different types: Type I, Type II, Type III, and Type IV. Type I and Type IV are the most common. Type I allergic reactions occur within minutes after exposure to an allergen. The most immediate of the four types, they can be severe and even fatal. A life-threatening Type I allergic reaction is known as anaphylaxis or “anaphylactic shock.” An example of this is severe allergic reaction to a bee sting. An allergy to shellfish that causes a person to break out in hives is another example of Type I.
Type I reactions can be local, such as a localized skin rash, or systemic. Local reactions may include asthma, rhinitis, hay fever, gastrointestinal upset, eczema (atopic dermatitis), and conjunctivitis. Other symptoms may include headache, fever, fatigue, diarrhea, and vomiting. (6) Symptoms of anaphylaxis include hives, itching, a severe drop in blood pressure, shock, irregular heartbeat,and swelling of the throat and larynx (voice box). Seizures may occur. The victim may feel hot, anxious, and have difficulty swallowing.
Type IV reactions, known as delayed hypersensitivity reactions, appear 24 to 72 hours after exposure to the allergen. Contact dermatitis from exposure to chemicals, plant toxins, or cosmetics is a delayed hypersensitivity reaction. Type IV reactions typically occur when small molecules called “haptens” bind with certain proteins in the blood. The immune response to this can result in localized tissue damage, causing symptoms such as red, itchy, and skin sores.
Hay fever (Allergic rhinitis) and conjunctivitis, (inflammation of the eyelid) are the most common manifestations of allergic reactions. These occur when environmental allergens contact mast cells in the membranes of the nose and eyes. Nasal congestion and discharge, sneezing, itchy eyes, and tearing are classic symptoms. Urticaria, or hives, is an allergic skin reaction characterized by round, elevated patches (wheals) with severe itching. Hives are most often caused by a reaction to food or drugs. Hives occur in outer layers of the skin. Angioedema is a similar reaction of the deep or subcutaneous layers of the skin. Urticaria and angioedema may last for as long as six weeks.
Allergic asthma is an immediate hypersensitive reaction that occurs in the lungs. The bronchial passages swell up and become inflamed, causing wheezing and difficult breathing. Severe attacks can produce the sensation of suffocating. Pollen, dust, smoke, automobile exhaust, and animal dander are antigens that commonly trigger allergic asthma.
Gastrointestinal allergies are involve mast cells of the GI tract. Exposure to antigens (most commonly food) produces nausea, cramping, vomiting, and diarrhea.
Atopic dermatitis (eczema) cause dry, scaling, itchy, cracked, and bleeding patches on the skin. Eczema can be triggered by exposure to dust, pollen, or antigenic foods. Contact dermatitis is another form of eczema. This type of reaction, therefore, can be an immediate or delayed allergic reaction.
Reactions Limited to Exposed Body Parts
- Runny nose
- Hay fever
- Stomach or intestinal upset
- Dry, scaling, itchy, cracked, and bleeding patches of skin
- Burning itching eyes
Severe Whole Body Reactions
- Itchy sensation
- Drop in blood pressure
- Irregular heart beats
- Swelling and closing of the throat
- Difficulty swallowing
Type IV Delayed Hypersensitivity
- Warm, flushed patches on the skin
- Itchy sensation
- Sores on the skin
- Allergic rhinitis and conjunctivitis presents as nasal congestion and discharge, sneezing, itchy swollen eyes, and tearing
- Urticaria or hives is characterized by round, elevated patches (wheals) on the skin with severe itching
- Angioedema is like hives and fluid build-up in the deep layers of the skin
- Allergic asthma can result in difficulty breathing and wheezing
- Allergies of the digestive tract nausea, cramping, vomiting, and diarrhea
- Atopic dermatitis or eczema is dry, scaling, itchy, cracked, and bleeding patches of skin
Identifying the specific allergens causing the allergic reaction is the first step in treating allergies. As allergens vary from person to person, individual testing is necessary. Scratch tests, intradermal tests, and serum (blood) antibody detection are the most common forms of allergy testing. Staying away from all known antigens is recommended, although this is often impractical, since the most common form of allergies, hay fever, is often triggered by just being outside when the pollens are heavy.
Treatment is designed mainly to reduce the allergic symptoms. The following medications provide relief from the symptoms of allergies:
Antihistamines are used to block histamine activity, relieve the inflammation, and decrease mucous production in the upper respiratory tract. Hay fever responds most successfully to antihistamines when taken before the pollen count rises. (7) Antihistamines also reduce hives and swelling of the skin. Side effects include insomnia, tremor, nervousness, irritability, dry mouth, constipation, urinary retention, rapid heartbeat, blurred vision, and drowsiness. The side effects of antihistamines often make them difficult to tolerate when taken over long periods. Non sedating antihistamines are available with a prescription. These antihistamines provide a majority of the benefits without the drowsiness. They include cetirizine, fexofenadine and loratadine.
Decongestants constrict the blood vessels of the mucous membrane, allowing mucous to drain more efficiently. Decongestants may be taken orally or in the form of a nasal spray. Side effects include restlessness, irritability, insomnia, and dependency. The dependency is characterized by a worsening of symptoms once the administration of drops or sprays is discontinued.
Cromolyn sodium inhibits the release of histamine and other inflammation-causing chemicals from mast cells. It can be taken as a nasal spray to protect the mucous membranes of the sinuses from allergic rhinitis (hay fever), or as an eye drop for allergic conjunctivitis. In some cases, cromolyn sodium is added to bronchial inhalers to help dilate the bronchial passages in asthma. Cromolyn sodium is rapidly excreted and has few adverse effects.
Steroidal inhalants may be used for severe, chronic allergic rhinitis. They reduce inflammation and decrease mucous production. Inhaled corticosteroids should not be used during acute allergic asthma attacks, as the powder can further irritate the lungs. Glucocorticoid residue from the spray may suppress immune defenses in the mouth and throat, causing thrush due to yeast overgrowth. Swallowed residues of these inhalants may be absorbed into the bloodstream, causing the same complications that occur when steroid drugs such as cortisone are taken orally.
Conventional treatment of allergic asthma includes anticholinergics (atropine) to relax the bronchials; beta-adrenergics (phenylpropanolamine, pseudoephedrine) which inhibit histamine release and relieve bronchoconstriction; and methyl xanthine (aminophylline) which also suppresses histamine release. (8) Combinations of inhalants containing cromolyn sodium and oral glucocorticoids, which prevent the release of histamine may be used in severe allergic asthma. Side effects of conventional asthma therapy include rapid heartbeat, gastrointestinal disturbances, nervousness, irritability, blood vessel constriction in the arms and leg, frequent urination, and increased susceptibility to infection.
In the 1940’s, it was first discovered that vitamin C was useful in the treatment of allergies. (9) It now appears that part of vitamin C’s usefulness in allergy treatment stems from the fact that it metabolizes, or detoxifies, histamine in the body In a small pilot study, 11 people who had either low vitamin C levels or elevated blood histamine levels were given 1 gm of vitamin C daily for three days. Blood histamine levels declined in every individual. (10) In another study, ascorbic acid decreased hay fever symptoms in 74 percent of patients. (11)
The amount of vitamin C necessary to provide therapeutic benefit can vary substantially from individual to individual. For example, one study evaluated 60 hay fever patients and found that about 50 percent of those taking 1 gram of vitamin C daily reported improvement, while about 75 percent of the people taking 2.25 grams daily improved. Linus Pauling, who was instrumental in educating people about the benefits of vitamin C, suggested that people with seasonal allergies consider increasing their vitamin C intake to bowel-tolerance level, (the highest daily dose that does not cause diarrhea) during allergy season. (12)
This nutrient been shown in many studies to reduce allergic reactions by inhibiting the release of histamine from mast cells. (13) Quercetin belongs to a class of compounds known as bioflavonoids, which frequently occur in nature along with vitamin C. Quercetin in conjunction with vitamin C reportedly helps to reduce the severity of symptoms in individuals with hay fever. (14)
Omega-3 Fatty Acids
Omega-3 fatty acids contain alpha linolenic acid, the starting material for the series 3 prostaglandins (PGE3), which are anti-inflammatory in nature. Flaxseed oil as well as fish oils are rich sources of omega-3. A minimum of an extra 400 IU of natural vitamin E should be taken daily when consuming supplemental omega-3. The omega-3/omega-6 fatty acid ratios tend to be out of balance in the diets of many people in the United States. The typical American diet tends to be high in omega-6 fatty acids and low in omega-3. Increasing intake of fish oils while cutting down on vegetable oils such as corn, safflower, and sunflower can help control the inflammation associated with allergies. (15)
Omega-6 Fatty Acids
In healthy individuals omega-6 fatty acid is broken down to gamma linolenic acid (GLA). Two of the best sources of GLA are borage oil (23%) and evening primrose oil (10%). Studies reveal that many people with allergic conditions have adequate blood levels of linoleic acid, but a deficiency of GLA. Supplementing GLA has proven to be of therapeutic benefit for patients with conditions such as allergic eczema. (16)
Bifidobacteria, Lactobacillus acidophilus
Probiotics containing lactobacillus acidophilus and bifidobacteria are important supplements for individuals with food allergies or intolerances. These are the “friendly bacteria” that are beneficial inhabitants of the digestive tract. In one study, every child that was suffering from symptoms related to food allergies had a deficiency of lactobacillus and bifidobacteria, along with an overgrowth of Enterobacteriaceae, a disease-causing bacteria.
Grape Seed Extract
Grapes seeds contain active ingredients called “proanthocyanidins.” Supplement labels may refer to these active ingredients as “PCO’s” or “OPC’s.” PCO’s are natural flavonoids that benefit the system by neutralizing “free radicals.” Normal byproducts of oxygen metabolism, free radicals can damage tissues if they build up to excess. Nutrients and other ingredients in foods and herbs that disable free radicals are called “antioxidants.” PCO’s are effective antioxidants. It has been reported to enhance the absorption of and work synergistically with vitamin C, which is also an antioxidant. (17) Vitamin C has been used for supportive care in allergies and asthma. PCO’s have been reported to inhibit the release of inflammation-causing chemicals such as histamine, leukotrienes, and prostaglandins. (18) , (19) This activity is beneficial in health conditions involving inflammation, such as allergies and asthma. In contrast, one study involving forty-nine sufferers of seasonal allergies showed no difference between grape seed extract and placebo. (20) Proanthocyanidins are reported to neutralize several classes of free radicals, including hydroxyl, lipid peroxides, and iron-induced lipid peroxidation. (21) , (22) , (23) They may also inhibit the enzyme xanthine oxidase, an enzyme that promotes free radical formation in tissues. (24)
The freeze-dried leaf of stinging nettle has been used in with some success in allergies. (25) A randomized, double-blind study of 92 individuals reported that a freeze-dried preparation of stinging nettle leaf was superior to placebo (dummy pill) in relieving the symptoms of allergic rhinitis (itching, watery eyes, runny nose). (26)
Coleus is a relatively new medicinal herb in the United States, although it has been extensively researched in India over the last twenty years. There have been studies published supporting its hypotensive (blood pressure lowering) and spasmolytic (muscle-relaxing) effects. (27) , (28) Most studies have been conducted with the isolated extract, forskolin, but current research indicates the whole plant may be actually more effective.
Diet & Lifestyle
- Avoid allergens as much as possible. There are a variety of air filtration devices for the home. Ozone purifiers and HEPA filtration are state of the art for home use in reducing mold, pollen, dander, and dust mites indoors.
- Reduce exposure to environmental pollutants, cigarette smoke, and other pollutants.
- Use hypoallergenic products whenever possible.
- Drink quality water, either filtered, reverse osmosis, or bottled.
- Reduce intake of meat and increase cold-water fish such as cod and salmon which are good sources of omega-3 fatty acids.
- Reduce the intake of vegetable oils such as corn, soy, sunflower, safflower, and canola. Use flaxseed oil.
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- View Abstract: Hara H, et al. Short chain fatty acids suppress cholesterol synthesis in rat liver and intestine. J Nutr. May1999;129(5):942-8.
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- View Abstract: Hara H, et al. Short chain fatty acids suppress cholesterol synthesis in rat liver and intestine. J Nutr. May1999;129(5):942-8.
- View Abstract: Profet M. The function of allergy: immunological defense against toxins. Q Rev Biol. Mar1991;66:23-62.
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- Ruskin SL. High dose vitamin C in allergy. Am J Dig Dis. 1945;12:281.
- View Abstract: Clemetson CA. Histamine and ascorbic acid in human blood. J Nutr. Apr1980;110(4):662-8.
- View Abstract: Podoshin L, et al. Treatment of perennial allergic rhinitis with ascorbic acid solution. Ear Nose Throat J. Jan1991;70(1):54-5.
- Pauling L. How to Live Longer and Feel Better. New York: W.H. Freeman and Company; 1986:201.
- View Abstract: Bronner C, Landry Y. Kinetics of the inhibitory effect of flavonoids on histamine secretion from mast cells. Agents Actions. 1985;16(3-4):147-151.
- Middleton E, Drzewicki G. Effect of ascorbic acid and flavonoids on human basophil release. J Allerg Clin Immunol. Jan1992:278.
- View Abstract: Kankaanpaa P, et al. Dietary fatty acids and allergy. Ann Med. Aug1999;31(4):282-7.
- View Abstract: Horrobin DF. Essential fatty acid metabolism and its modification in atopic eczema. Am J Clin Nutr. Jan2000;71(1 Suppl):367S-72S.
- Maffei Facino R, et al. Regeneration of Endogenous Antioxidants, Ascorbic Acid, Alpha Tocopherol, by the Oligomeric Procyanide Fraction of Vitus vinifera L:ESR Study. Boll Chim Farm. 1997;136(4):340-44.
- View Abstract: Maffei Facino R, et al. Procyanidines from Vitis vinifera Seeds Protect Rabbit Heart from Ischemia/Reperfusion Injury: Antioxidant Intervention and/or Iron and Copper Sequestering Ability. Planta Med. 1996;62(6):495-502.
- View Abstract: Maffei Facino R, et al. Free Radicals Scavenging Action and Anti-enzyme Activities of Procyanidines from Vitis vinifera. A Mechanism for Their Capillary Protective Action. Arzneim-Forsch/Drug Res. 1994;44(5):592-601.
- View Abstract: Bernstein CK, Deng C, Shuklah R, et al. Abstract 1018 Double Blind Placebo Controlled (DBPC) Study of Grapeseed Extract in the Treatment of Seasonal Allergic Rhinitis (SAR). American Academy of Allergy, Asthma and Immunology (AAAAI) 57th Annual Meeting. Mar2001.
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- View Abstract: Fitzpatrick DF, et al. Endothelium-dependent Vasorelaxing Activity of Wine and Other Grape Products. Am J Physiol. 1993;265(2 Pt 2):H774-H778.
- Uchida S, et al. Active Oxygen Free Radicals Are Scavenged by Condensed Tannins. Prog Clin Biol Res. 1988;280:135-38.
- View Abstract: Hatano T, et al. Effects of Interaction of Tannins with Co-existing Substances. VII. Inhibitory Effects of Tannins and Related Polyphenols on Xanthine Oxidase. Chem Pharm Bull (Tokyo). 1990;38(5):1224-29.
- View Abstract: Mittman P, et al. Randomized, Double-blind Study of Freeze-dried Urtica dioica in the Treatment of Allergic Rhinitis. Planta Medica. Feb1990;56(1):44.
- View Abstract: Mittman P. Randomized, Double-blind Study of Freeze-dried Urtica dioica in the Treatment of Allergic Rhinitis. Planta Med. Feb1990;56(1):44-47.
- View Abstract: Bhat SV, et al. The Antihypertensive and Positive Inotropic Diterpene Forskolin: Effects of Structural Modifications on Its Activity. J Med Chem. 1983;26:486-92.
- View Abstract: Baumann G, et al. Cardiovascular Effects of Forskolin (HL 362) in Patients with Idiopathic Congestive Cardiomyopathy — A Comparative Study with Dobutamine and Sodium Nitroprusside. Cardiovasc Pharmacol. 1990;16(1):93-100.