domingo, 21 de abril de 2013

Seasonal Allergies at a Glance | NCCAM

Seasonal Allergies at a Glance | NCCAM

The National Center for Complementary and Alternative Medicine (N C C A M): Part of the National Institutes of Health

Seasonal Allergies at a Glance

Seasonal allergies, also called allergic rhinitis or hay fever, are common among both adults and children. They occur when the immune system, which defends the body against foreign invaders such as bacteria, responds to a false alarm. In a person who has an allergy, the immune system treats a normally harmless substance as a threat and attacks it, producing symptoms of an allergic reaction.
This page discusses complementary health approaches for allergic rhinitis. Another page on the NCCAM Web site has information on complementary approaches for asthma.
What the Science Says
Many complementary health approaches have been studied for allergic rhinitis. There is some evidence that a few may be helpful.
  • Rinsing the sinuses with a neti pot (a device that comes from the Ayurvedic tradition) or with other devices, such as bottles, sprays, pumps, or nebulizers, may be a useful addition to conventional treatment for allergic rhinitis.
  • There have been several studies in Europe of the herb butterbur for allergic rhinitis, most of which indicated that butterbur may be helpful.
  • It has been thought that eating honey might help to relieve seasonal allergies because honey contains small amounts of pollen and might act as a form of immunotherapy. Another possibility is that honey could act as an antihistamine or anti-inflammatory agent. Only a few studies have examined the effects of honey in people with seasonal allergies, and there is no convincing evidence that honey can relieve allergy symptoms.
  • Many other natural products have been studied for allergic rhinitis, including astragalus, capsaicin, grape seed extract, omega-3 fatty acids, probiotics, Pycnogenol (French maritime pine bark extract), quercetin, spirulina, stinging nettle, and an herb used in Ayurvedic medicine called tinospora or guduchi. In all instances, the evidence is either inconsistent or too limited to show whether these products are helpful.
  • It is uncertain whether acupuncture can be helpful for allergic rhinitis. A few studies have evaluated acupuncture for this condition, but their results have been inconsistent.
Side Effects and Risks
  • People can get infections if they use neti pots or other nasal rinsing devices improperly. The U.S. Food and Drug Administration (FDA) has information on how to rinse your sinuses safely.
    • Most important is the source of water that is used with nasal rinsing devices. According to the FDA, tap water that is not filtered, treated, or processed in specific ways is not safe for use as a nasal rinse. Sterile water is safe; over-the-counter nasal rinsing products that contain sterile saline (salt water) are available.
    • Some tap water contains low levels of organisms, such as bacteria and protozoa, including amoebas, that may be safe to swallow because stomach acid kills them. But these organisms can stay alive in nasal passages and cause potentially serious infections. Improper use of neti pots may have caused two deaths in 2011 in Louisiana from a rare brain infection that the state health department linked to tap water contaminated with an amoeba called Naegleria fowleri.
  • Raw butterbur extracts contain pyrrolizidine alkaloids, which can cause liver damage and cancer. Extracts of butterbur that are almost completely free from these alkaloids are available. However, no studies have proven that the long-term use of butterbur products, including the reduced-alkaloid products, is safe.
  • Acupuncture is generally considered safe when performed by an experienced practitioner using sterile needles. Improperly performed acupuncture can cause potentially serious side effects.
  • Be cautious about using herbs or bee products for any purpose. Some herbs, such as chamomile and echinacea, may cause allergic reactions in people who are allergic to related plants. Also, people with pollen allergies may have allergic reactions to bee products, such as bee pollen, honey, royal jelly, and propolis (a hive sealant made by bees from plant resins). Children under 1 year of age should not eat honey.
Talk to your health care provider about the best way to manage your seasonal allergies, especially if you are considering or using a dietary supplement. Be aware that some supplements may interact with medications or other supplements or have side effects of their own. Keep in mind that most dietary supplements have not been tested in pregnant women, nursing mothers, or children.

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