Rhinitis is the medical term for inflammation of the nose. Viruses, bacteria, allergens, and irritants can cause inflammation of the nasal mucus membrane, which results in rhinitis. Once inflamed, the nose produces excessive mucous, which causes a runny nose, nasal congestion, and postnasal drip (when mucus drips from the sinuses, down the throat).
Allergic rhinitis is one of the most common allergies. This type of rhinitis occurs when the body's immune system overreacts to an airborne substance that is normally harmless (allergen), such as mold, pollen, animal dander, or dust mites. Once the allergen is inhaled through the nose, white blood cells of an allergic individual produce an antibody called immunoglobulin E (IgE). This immunoglobulin attaches to the allergen, which triggers the release of histamine and other inflammatory chemicals that cause allergic rhinitis symptoms, such as runny nose and nasal congestion.
Allergic rhinitis may occur as either acute (short-term) or chronic (long-term). Acute rhinitis is short-term and classified as the common cold, while chronic rhinitis is recurrent, with periods of remission in between. Chronic rhinitis lasts three months or longer.
There are two types of allergic rhinitis - seasonal allergic rhinitis and perennial allergic rhinitis.
Seasonal allergic rhinitis, also called pollinosis, hay fever, or nasal allergies, is characterized by several symptoms, predominantly in the nose and eyes. Symptoms occur after airborne allergens like dust, dander, or pollen are inhaled. When pollens cause the allergic symptoms, the allergic rhinitis is commonly referred to as "hay fever." According to the American Lung Association, an estimated 26.1 million Americans have hay fever symptoms each year. 14.6 million Americans have asthma, which often accompanies hay fever.
Perennial allergic rhinitis is an allergic reaction to allergens (substances that can cause an allergic reaction) that is not seasonal. Instead, symptoms are persistent and generally less severe than seasonal allergic rhinitis.
Some individuals, especially children, may outgrow allergic rhinitis as the immune system becomes less sensitive to certain allergens. Minimizing exposure to known allergens may help prevent or reduce allergy symptoms. Treatment for allergic rhinitis depends on the severity and frequency of the symptoms. Patients may benefit from allergy medications like antihistamines, mast cell stabilizers, decongestants, leukotriene receptor antagonists, and nasal corticosteroid sprays.
NON-ALLERGIC TYPES OF RHINITIS
Atrophic rhinitis: Atrophic rhinitis is a chronic inflammation of nose. It causes the nasal mucosa, including the glands, turbinate bones, and nerves in the nose, to atrophy (shrink). It may also cause a foul-smelling nasal discharge. Patients may experience nosebleeds and may lose their sense of smell. This condition may be the result of a sinus surgery or prolonged bacterial infection of the nose.
Snuffles: Patients born with syphilis (a sexually transmitted disease) may experience rhinitis. When syphilis is the cause of the symptoms, the condition is called snuffles.
Vasomotor rhinitis: Vasomotor rhinitis, also known as non-allergenic rhinitis, is thought to be the result of nerve disorders. Vasomotor rhinitis, unlike allergic rhinitis, does not involve the immune system. Instead, this form is caused by oversensitive or excessive blood vessels in the nasal membrane. The body overreacts to stimuli such as changes in weather, temperature, barometric pressure, chemical irritants, aerosol sprays, psychological stress, or certain types of medication. The exact cause of vasomotor rhinitis is not well understood. It is possible for patients to suffer from vasomotor rhinitis and allergic rhinitis at the same time.
Airborne substances, known as allergens, cause allergic rhinitis. These allergens are usually harmless and only cause allergic symptoms in some people.
Typically, an allergic response is not triggered the first time the body encounters the allergen. The first, or several times after the body is exposed to an allergen, the immune system becomes sensitized. During this process, the body's white blood cells develop immunoglobulin E (IgE) antibodies to the dust mite allergens. Once sensitized, the antibodies quickly detect and bind to the allergens in the body. These antibodies also trigger the release of chemicals (like histamine) that cause allergic symptoms, such as runny nose and sneezing.
Common outdoor allergens, such as pollen, grass, and trees, can cause seasonal allergic rhinitis. When pollen causes allergic rhinitis, the condition is often referred to as hay fever.
Common indoor allergens, such as animal dander, mold, and dust, can cause allergic perennial allergic rhinitis.
Symptoms of allergic rhinitis vary greatly among individuals. Common symptoms include: cough, headache, itchy nose, itchy mouth, itchy throat, itchy skin, nosebleeds, impaired smell, watery eyes, sore throat, wheezing, fever, cross-reactivity allergy to some fruits, pinkeye, nasal congestion, post-nasal drip, runny nose, and swelling of the nasal tissues (can cause headaches). Some patients, especially those suffering from vasomotor rhinitis, sneeze when transitioning from a cold room to a warmer one.
Infection: A secondary bacterial infection may occur in tissues like the mucous membranes of the nose, throat, sinuses, or the ear. Common secondary infections related to hay fever include ear infections and sinus infections. In children, hay fever is often a contributing factor to middle ear infections.
Prolonged sinus congestion caused by hay fever may increase an individual's susceptibility to developing a sinus infection.
Allergic conditions: Patients who have hay fever have an increased risk of developing more serious allergic conditions like asthma. It is common for hay fever and asthma to occur at the same time. Patients suffering from hay fever may also have eczema, a skin disorder that causes red, dry flaky skin.
Other: Additional complications of allergic rhinitis include nosebleeds, decreased lung function, and enlarged lymph nodes in the nose and throat.
General: Healthcare providers should take a careful medical history to determine whether the patient's symptoms vary depending on the time of day or season. A skin test or allergen-specific immunoglobulin E (IgE) test may be performed to pinpoint specific allergens that are causing the symptoms.
Skin test: A skin test is used to determine whether a patient is allergic to certain substances, such as mold, dust mites, or animal dander. During the test, the skin is exposed to different allergy-causing substances (allergens) and then observed for an allergic reaction. Some tests, such as the percutaneous (puncture, prick or scratch) test, detect immediate allergic reactions that develop within minutes of exposure to an allergen. Other tests, such as the epicutaneous (patch) test, detect delayed allergic reactions that develop over the course of several days. If an allergen triggers an allergic reaction to a test, the patient will develop reddening, swelling, or a raised, itchy red wheal (bump) that looks similar to a mosquito bite. The healthcare provider will measure the size of the wheal and record the results. The larger the wheal, the more severe the allergy.
Allergen-specific immunoglobulin E (IgE) test: An allergen-specific immunoglobulin E (IgE) test, commonly often referred to as radioallergosorbent test (RAST©), is a type of blood test that can help determine if a patient who experiences allergy symptoms, such as runny nose, watery eyes, and hives, is allergic to particular substances called allergens.
The in vitro test (performed outside of the body in a laboratory setting) exposes a blood sample to suspected allergens (like dust mites, pollen or animal dander) to determine whether the patient has developed allergen-specific immunoglobulin E (IgE) antibodies. Antibodies are proteins that recognize and bind to specific antigens.
During the procedure, a sample of blood is taken from the patient. The blood is then sent to a laboratory that performs specific IgE blood tests. An allergen-antigen complex is bound to a paper disc called an allergosorbent, and the patient's blood is added. If the blood contains antibodies to the specific antigen, it will bind to the "tagged" immunoglobulins.
RAST© is less accurate than a skin test. However, if the patient has a severe skin disease (such as eczema or psoriasis) that is present on large areas of skin on the arms or back, a skin test conclusive test. For these patients, an allergen-specific IgE test is the preferred diagnostic method.
General: Treatment for allergic rhinitis depends on the severity and frequency of the symptoms. Patients may benefit from allergy medications like antihistamines, mast cell stabilizers, decongestants, leukotriene receptor antagonists, and nasal corticosteroid sprays. Minimizing exposure to known allergens may also help prevent or reduce allergy symptoms.
Allergen immunotherapy: Allergen immunotherapy, also known as allergy shots, is often used to treat patients who suffer from severe allergies or for those who experience allergy symptoms more than three months a year. Allergen immunotherapy involves injecting increasing amounts of an allergen to a patient over several months. Immunotherapy does not cure allergies, but it may help reduce the body's sensitivity to certain substances. During therapy, some patients may not experience any allergy symptoms.
Short-acting antihistamines: Short-acting antihistamines, such as diphenhydramine (Benadryl©), have been used to relieve mild to moderate allergy symptoms. Most short-acting antihistamines are available over-the-counter. These medications typically take about 15-30 minutes to take effect, and more than one dose may be taken in a single day. Most short-acting antihistamines are taken every four to six hours, depending on symptoms. Patients should carefully read the packaging labels and follow the directions of their healthcare providers and pharmacists.
Short-acting antihistamines medications often cause drowsiness. Many short-acting antihistamines have been shown to impair cognition (slow learning) in children, even in the absence of drowsiness. Therefore, these drugs are generally not recommended in children, unless taken under the strict supervision of their healthcare providers. Loratadine (Claritin©), which is now available over-the-counter, does not cause drowsiness or affect learning in children.
Longer-acting antihistamines: Longer-acting antihistamines, such as fexofenadine (Allegra©) or cetirizine (Zyrtec©), are available by prescription for mild to moderate allergy symptoms. These medications are generally taken once a day to relieve long-term allergies to allergens like pet dander.
These medications cause less drowsiness than short-acting antihistamines, and they are equally effective. While these drugs usually do not interfere with learning, they should be only be used in children under the strict supervision of their healthcare providers. Common side effects may include drowsiness, dry mouth, headache, sore throat, stomach pain, vomiting, or diarrhea.
Decongestant pills or sprays: Decongestants can be used to relieve nasal congestion (stuffy nose) when the patient is not responding to other allergy medications like antihistamines or cromolyn sodium. Decongestant nasal sprays should not be used for long periods of time. Nasal spray decongestants like oxymetazoline (Afrin©) should not be used more than twice daily for three consecutive days because rebound congestion may occur. This means that symptoms of nasal congestion will return.
Ipratropium (Atrovent©): Ipratropium is a nasal spray that has been used to reduce a runny nose. Patients who are allergic to peanuts should not take Atrovent© because it is manufactured with peanut products.
Leukotriene receptor antagonists: Leukotriene receptor antagonists block the action of leukotrienes, which are also important mediators of the allergic response. New leukotriene receptor antagonists, such as montelukast (Singulair©) and zafirlukast (Accolate©), can effectively treat rhinitis without some of the common side effects like drowsiness. These long-acting medications are taken once daily.
Mast cell stabilizers: Mast cell stabilizers like cromolyn sodium have been used to treat symptoms of hay fever. Cromolyn sodium is available over-the-counter as a nasal spray (Nasalcrom©) to treat hay fever. Eye drop versions of cromolyn sodium are also available for itchy, bloodshot eyes. Cromolyn sodium does not cause rebound congestion.
Nasal corticosteroid sprays: Nasal corticosteroid sprays are the strongest medications that treat allergic rhinitis. Corticosteroid sprays reduce and control the effects of the mediators that cause inflammation of the nose. These medications have been shown to improve symptoms of allergic rhinitis, including sneezing, itching, and runny nose. Commonly prescribed nasal corticosteroids include fluticasone (Flonase©), mometasone (Nasonex©), and triamcinolone (Nasacort©). Symptoms will not start to improve for at least 12 hours after the medication is taken. Nasal corticosteroid sprays do not cause rebound congestion.
Good scientific evidence :
Bromelain : Bromelain has been studied in various clinical studies for sinusitis with mixed results. Further research is necessary. Avoid if allergic to bromelain, pineapple, honeybee, venom, latex, birch pollen, carrots, celery, fennel, cypress pollen, grass pollen, papain, rye flour, wheat flour, or members of the Bromeliaceae family. Use cautiously with history of bleeding disorder, stomach ulcers, heart disease, liver or kidney disease. Use caution before dental or surgical procedures or while driving or operating machinery. Avoid if pregnant or breastfeeding.
Butterbur : Good scientific evidence suggests that butterbur may be effective for allergic rhinitis prevention in susceptible individuals. Comparisons of butterbur to prescription drugs, such as fexofenadine (Allegra©) and cetirizine (Zyrtec©), have reported similar efficacy. Additional studies are warranted before a firm conclusion can be made.
Avoid if allergic or hypersensitive to Petasites hybridus or other plants from the Asteraceae/Compositae family (such as ragweed, marigolds, daisies, and chrysanthemums). Raw, unprocessed butterbur plant should not be eaten due to the risk of liver or kidney damage or cancer. Avoid if pregnant or breastfeeding.
Nasal irrigation : There is good evidence from clinical studies to recommend the use of nasal irrigation in the treatment of allergic rhinitis. One study demonstrated that reflexology massage may be equally effective; however, the advantage of irrigation (i.e. inexpensive, performed at home, minimal adverse side effects) makes the technique beneficial. Methodological and statistical reporting are lacking in some of these trials. A well-conducted, randomized controlled trial, fully reporting data would make the case for allergic rhinitis stronger.
Early research suggests that nasal irrigation may help treat chronic sinusitis, with improvements in sinus-related quality of life, decreases in symptoms, and decreases in medication use. Further study is needed before a conclusion can be made.
Nasal irrigation is generally well tolerated. Use cautiously with history of frequent nosebleeds. If the irrigation liquid is hot, the nose may become irritated.
Probiotics : Use of probiotic Enterococcus faecalis bacteria in hypertrophic sinusitis (sinus inflammation) may reduce frequency of relapses and the need for antibiotic therapy. Further research is necessary before a firm conclusion can be made. Probiotics are generally considered safe and well tolerated. Avoid if allergic or hypersensitive to probiotics. Use cautiously if lactose intolerant.
Unclear or conflicting scientific evidence :
Acupuncture : There is currently insufficient available evidence on which to base recommendations for acupuncture in non-allergic rhinitis. However, studies suggest that it may offer possible benefits. Additionally, more studies are needed of stronger design to determine whether or not acupuncture offers benefit in sinusitis.
Acupuncture should be avoided in patients with heart disease, pulmonary disease, infections, bleeding disorders, medical conditions of unknown origin, or neurological disorders. Pregnant women, the elderly, diabetics, people with a history of seizures, and those receiving radiation therapy and/or taking drugs increasing bleeding risks should also avoid acupuncture.
Aromatherapy : Despite widespread use in over-the-counter agents and vapors, there is not enough scientific evidence to recommend use of eucalyptus oil as a decongestant-expectorant (by mouth or inhaled form). Essential oils should be administered in a carrier oil to avoid toxicity. Avoid with a history of allergic dermatitis. Use cautiously if driving/operating heavy machinery. Avoid consuming essential oils. Avoid direct contact of undiluted oils with mucous membranes. Use cautiously if pregnant.
Black seed : Studies in patients with allergies found that black seed decreased subjective measures of severity of allergies. The effect of black seed for allergies is still not clear and further study is required before a conclusion can be made. Avoid with a known allergy/hypersensitivity to black seed, its constituents, black seed oil, or to members of the Ranunculaceae family. Allergic contact dermatitis has been reported after topical use of black seed or the oil from the seed.
Cat's claw : It has been suggested that cat's claw may help treat allergies and related respiratory diseases. However, there is currently limited scientific evidence to support this claim. More well-designed trials are needed to determine whether cat's claw is a beneficial treatment.
Avoid if allergic to cat's claw or Uncaria plants or plants in the Rubiaceae family, such as gardenia, coffee, or quinine. Avoid with history of conditions affecting the immune system (such as AIDS, HIV, some types of cancer, multiple sclerosis, tuberculosis, rheumatoid arthritis, lupus). Use cautiously with bleeding disorders or with history of stroke, or if taking drugs that may increase the risk of bleeding. Stop use two weeks before surgery/dental/diagnostic procedures with bleeding risk, and do not use immediately after these procedures. Avoid if pregnant or breastfeeding. Cat's claw may be contaminated with other Uncaria species. Reports exist of the potentially toxic Texan-grown plant Acacia gregii being substituted for cat's claw.
Choline : Oral tricholine citrate (TRI) effectively relieved allergic rhinitis symptoms in limited available study. Further research is needed before a firm conclusion can be made. Choline is generally regarded as safe and appears to be well tolerated. Avoid if allergic to choline, lecithin, or phosphatidylcholine.
Elder : Elder may offer benefits for bacterial sinusitis, such as reducing excessive mucus secretion. Herbal preparations containing elder may result in less swelling of mucus membranes, better drainage, milder headache, and decreased nasal congestion. Cyanide toxicity is possible. Avoid if allergic to elder or to plants related to honeysuckle. Some reports exist of allergies from contact with fresh elder stems. Use caution with diabetes, high blood pressure or urinary problems, or with drugs used for any of these conditions. Use caution with anti-inflammatories, diuretics ("water pills" for high blood pressure), or laxatives. Avoid if pregnant or breastfeeding.
Ephedra : Preliminary study suggests that ephedrine nasal spray may help treat allergic rhinitis. Additional research is needed before a recommendation can be made.
Ephedra taken by mouth can cause serious side effects, including heart attack, seizure, and stroke. Therefore, ephedrine nasal sprays should only be used in the nose. The U.S. Food and Drug Administration (FDA) has collected thousands of reports of serious toxicity linked to ephedra (including over 100 deaths). Ephedra products are banned from dietary supplements because of serious health risks, including heart attack, heart damage, breathing difficulties, and fluid retention in the lungs. Avoid with history of high blood pressure, abnormal heart rate, heart attack, stroke, seizure, eating disorders, anxiety, prostate disease, mental illness, kidney disease, stomach ulcers, heart disease, eye disease, depression, diabetes, thyroid disease, or sleep problems. Avoid if pregnant or breastfeeding.
Eucalyptus oil : There is currently insufficient available evidence to recommend either for or against eucalyptus oil as a decongestant-expectorant. Studies show that eucalyptus oil may be effective for treating upper respiratory tract infections. Avoid if allergic to eucalyptus oil or with a history of seizure, diabetes, asthma, heart disease, abnormal heart rhythms, intestinal disorders, liver disease, kidney disease, lung disease, or the blood condition known as acute intermittent porphyria. Use caution if driving or operating machinery. A strain of bacteria found on eucalyptus may cause infection. Toxicity has been reported with oral and inhaled use.
Honey : Currently, there is insufficient human evidence to recommend honey for the treatment of rhinoconjunctivitis. Avoid if allergic or hypersensitive to honey, pollen, celery or bees. Honey is generally considered safe in recommended doses. Avoid honey from the genus Rhododendron because it may cause a toxic reaction. Avoid in infants younger than 12 months of age. Use cautiously with antibiotics. Potentially harmful contaminants (like C. botulinum or grayanotoxins) can be found in some types of honey and should be used cautiously in pregnant or breastfeeding women.
Horseradish : Several studies suggest that some horseradish constituents may offer antibiotic activity and may help treat sinusitis. Additional high-quality clinical studies are needed before a conclusion can be made. Avoid if allergic or hypersensitive to horseradish (Armoracia rusticana), its constituents, or members of the Brassicaceae family. Large oral doses may provoke allergic reactions. Use cautiously with clotting disorders, hypotension (low blood pressure), thyroid disorders, kidney disorders and inflammation, gastrointestinal conditions, and ulcers. Use cautiously if taking anticoagulants or antiplatelets (blood thinning agents), antihypertensives (blood pressure-lowering agents), anti-inflammatory agents, or thyroid hormones. Use cautiously if undergoing treatment for cancer. Avoid medicinal amounts of horseradish if pregnant or breastfeeding; based on herbal textbooks and folkloric precedent, horseradish has been used to induce abortion.
Hypnotherapy, hypnosis : It has been suggested that hypnotherapy may be effective for allergies and may help treat hay fever. However, further research is necessary. Use cautiously with mental illnesses such as psychosis/schizophrenia, manic depression, multiple personality disorder, or dissociative disorders. Use cautiously with seizure disorders
Kiwi : Conclusive data on kiwi's therapeutic benefits for preventing lung conditions and other respiratory problems is currently lacking. Kiwi and other fruits high in vitamin C may benefit lung conditions in children, especially wheezing. More research is warranted before a recommendation can be made. Avoid if allergic or hypersensitive to kiwi, latex, birch pollen, banana, chestnut, fig, flour, melon, poppy seeds, rye grain, sesame seeds, and related substances. Kiwi is generally considered safe when taken in amounts naturally found in foods. Use cautiously with anti-platelet drugs like aspirin, cilostazol, or clopidogrel. Use cautiously with hormone therapies or serotonergic drugs. Avoid if pregnant or breastfeeding because clinical trials testing safety in supplemental doses are currently lacking. The amount found in foods appears to be safe in most people.
Lactobacillus acidophilus : Limited available study suggests that the Lactobacillus acidophilus (L. acidophilus) strain L-92 (L-92) may be effective for the treatment of Japanese cedar-pollen allergy. Further research is needed to confirm these results. L. acidophilus may be difficult to tolerate if allergic to dairy products containing L. acidophilus. Avoid with history of an injury or illness of the intestinal wall, immune-disease, or heart valve surgery. Avoid with prescription drugs, such as corticosteroids, because of the risk of infection. Use cautiously with heart murmurs. Antibiotics or alcohol may destroy L. acidophilus. Therefore, it is recommended that L. acidophilus be taken three hours after taking antibiotics or drinking alcohol. Some individuals may use antacids, such as famotidine (Pepcid©) and esomeprazole (Nexium©), to decrease the amount of acid in the stomach one hour before taking L. acidophilus.
MSM : According to preliminary clinical study, MSM reduces symptoms associated with seasonal allergic rhinitis (SAR). However, larger controlled trials are needed to confirm these findings. Avoid if allergic or hypersensitive to MSM. Long-term effects of supplementation with MSM have not been examined. Avoid if pregnant or breastfeeding.
Onion : Research shows that topical application of an alcoholic onion extract significantly reduced responses to allergies. Although intriguing, more research is needed in this area to establish the efficacy and dosing of topical onion extracts. Avoid if allergic or hypersensitive to onion (Allium cepa), its constituents, or members of the Lilaceae family. Use cautiously with hematologic (blood) disorders, diabetes, hypoglycemia (low blood sugar), and hypotension (low blood pressure). Use cautiously if taking anticoagulants or antiplatelets (blood thinners). Avoid medicinal doses if pregnant or breastfeeding.
Perilla : Preliminary evidence suggests some benefit of perilla extract for seasonal allergies. Further clinical trials are required before conclusions can be made. Avoid if allergic/hypersensitive to perilla or members of the Lamiaciae/Labiatae family. Use cautiously with cancer, low HDL-cholesterol, and immune disorders. Use cautiously if taking NSAIDS or barbiturates. Avoid if pregnant or breastfeeding.
Probiotics : Only a few types and combinations of probiotics have been studied as a possible allergy treatment. They have been studied mostly in children, teenagers, and young adults. Further research is necessary before a firm conclusion can be made. Probiotics are generally considered safe and well tolerated. Avoid if allergic or hypersensitive to probiotics. Use cautiously if lactose intolerant.
Sorrel : Research suggests that an herbal combination preparation containing sorrel, Sinupret©, may have beneficial effects in improving symptoms of sinusitis when used with antibiotics. It is not clear if these same effects would be seen with sorrel alone or what dose may be safe and effective. For allergic rhinitis, there is not enough evidence to make a conclusion at this time. More research of sorrel alone is needed.
Avoid sorrel with a known allergy to sorrel or any of its constituents. Avoid large doses of sorrel because there have been reports of toxicity and death. Many tinctures contain high levels of alcohol and should be avoided when driving or operating heavy machinery. Sorrel formulations may cause nausea or vomiting when taken with the prescription drugs metronidazole (Flagyl©) or disulfiram (Antabuse©). Avoid if pregnant or breastfeeding.
Spirulina : Anti-inflammatory properties of spirulina may help improve symptoms of allergic rhinitis. However, further high-quality studies are needed to confirm these findings. Avoid if allergic or hypersensitive to spirulina or blue-green algae. Use cautiously with phenylketonuria (a genetic disorder of a liver enzyme that disrupts normal body functions), autoimmune diseases, bleeding disorders, diabetes, and osteoporosis. Use cautiously with products containing the blue-green algae species Anabaena spp., Aphanizomenon spp., and Microcystis spp.; in underweight patients or in those taking antiobesity agents or appetite suppressants; of if consuming a high-protein diet. Avoid in children or if pregnant or breastfeeding.
Stinging nettle : For many years, a freeze-dried preparation of Urtica dioica has been prescribed by physicians and sold over-the-counter for the treatment of allergic rhinitis. Clinical trials demonstrating statistical significance over placebo and/or equivalence with other available treatments are needed to support the use of nettle in the treatment of allergic rhinitis.
Avoid if allergic or hypersensitive to nettle, the Urticaceae family or any ingredient of nettle products. Use cautiously with diabetes, bleeding disorders, and/or low sodium levels in the blood. Use cautiously with diuretics and anti-inflammatory drugs. The elderly should also use nettle cautiously. Avoid if pregnant or breastfeeding.
Thymus extract : Thymus extract may reduce allergy symptoms due to its potential immune stimulating effects. More clinical trials are required before recommendations can be made involving thymus extract for this use. Avoid if allergic or hypersensitive to thymus extracts. Use bovine thymus extract supplements cautiously due to potential for exposure to the virus that causes "mad cow disease." Avoid use with an organ transplant or other forms of allografts or xenografts. Avoid if receiving immunosuppressive therapy, with thymic tumors, myasthenia gravis (neuromuscular disorder), untreated hypothyroidism, or if taking hormonal therapy. Avoid if pregnant or breastfeeding; thymic extract increases human sperm motility and progression.
Vitamin E : Although thought to aid in reducing the nasal symptoms of allergic rhinitis, vitamin E intake may not be effective. Current evidence is limited, however, and more studies are needed before a firm conclusion can be drawn.
Avoid if allergic or hypersensitive to vitamin E. For short periods of time, vitamin E supplementation is generally considered safe at doses up to 1,000 milligrams per day. Avoid doses higher than 1,000 milligrams a day. Avoid with retinitis pigmentosa (loss of peripheral vision). Use cautiously with bleeding disorders. The recommended dose of vitamin E for pregnant women of any age is 15 milligrams; for breastfeeding women of any age, the recommended dose is 19 milligrams. Use beyond this level in pregnant women is not recommended.
Fair negative scientific evidence :
Grape seed : Grape seed has been used to treat immune system disorders due to its antioxidant effects. However, a well-designed human study of allergic rhinitis sufferers showed no improvement in allergy symptoms with administration of grape seed extract ingredients. Avoid if allergic or hypersensitive to grapes or other grape compounds. Use cautiously if taking blood thinners such as warfarin, aspirin, non-steroidal anti-inflammatory drugs (NSAIDS), or anti-platelet agents. Use cautiously with bleeding disorders or if taking drugs that may increase the risk of bleeding. Use cautiously with drugs processed using the liver's "cytochrome P450" enzyme system. Use cautiously with blood pressure disorders or if taking ACE inhibitors. Avoid with disorders that increase the risk of bleeding or with active bleeding disorders (stomach ulcers, bleeding into the brain, etc.). Avoid if pregnant or breastfeeding.
Avoid exposure to known allergens. If allergic to pollen, remain indoors in the morning and evening when outdoor pollen levels are highest.
Individuals who cannot avoid exposure to known allergens may benefit from preventative allergy medications, such as antihistamines.
Keep windows closed and, if possible, use the air conditioner in the house and/or car.
Do not dry clothes outside.
Avoid unnecessary exposure to environmental irritants, such as insect sprays, tobacco smoke, air pollution, and fresh tar or paint.
Regularly wash the hands and face to remove pollen.
A humidifier may help remove some of the allergens out of the air.
There is evidence that infants who are exposed to airborne allergens, such as dust mites and animal dander, may be less likely to develop related allergies.
Consider installing central air conditioning with a high-efficiency particulate air (HEPA) filter attachment. The HEPA filter can trap airborne allergens (such as mold spores, dust mites, and pollen) from outdoor air, preventing them from circulating in the air inside.
Consider using a vacuum cleaner with a double-layered microfilter bag or a HEPA filter.
This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
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