Echinacea, the popular herbal remedy used to strengthen the immune system and fight infection, is reportedly being used by some consumers to treat allergies, asthma and skin disorders. The herb, however, is not recommended for those uses and can have negative effects, a new study shows.
The Australian study was published in the January 2002 issue of the peer-reviewed journal Annals of Allergy, Asthma and Immunology, a publication of the American College of Allergy, Asthma and Immunology.
Rob McCaleb, founder and president, Herb Research Foundation, said he doesn't expect a lot of fallout from the study. "I don't think anyone is promoting echinacea for allergy use. Allergies are caused by hypersensitivity of the immune system, so something that stimulates the immune system is probaby not a good idea. It seems counterintuitive."
Although prior analysis suggests some herbal regimens for asthma and allergies are scientifically justified, their increased use raises concerns about potentially serious risks and the need for more research, wrote Leonard Bielory, M.D., of the New Jersey Medical School, Newark, in an editorial accompanying the study. "To protect the common good, there is a need to know not only what CAM can do for us, but also what it can do to us," he wrote.
Normally, individuals need direct exposure to a substance before experiencing an allergic reaction. But the Australian researchers advised that "given the popularity of echinacea, even rare adverse events become inevitable when a large proportion of the population uses it mostly unsupervised. Because these reactions may occur even with their first ever known exposure, atopic patients should be cautioned appropriately."
Atopic patients are hypersensitive, possibly from hereditary causes, to hayfever, asthma, eczema and other allergies of the nose, airways and skin, explains Marianne Frieri, M.D., director of allergy and immunology at Nassau University Medical Center, East Meadow, N.Y. They are more likely to develop cross-reactive allergic responses to compounds that are structurally or botanically related.
Hypersensitivity reactions have been triggered by royal jelly, pollen preparations, chamomile, birch pollen and other plant compounds.
Echinacea is a member of the Asteraceae (Compositae) family, other members include species of Ambrosia (ragweed), Artemisia (mugwort and sagebrush), as well as chrysanthemums, dahlias, daisies, marigolds and sunflowers.
"Anyone taking echinacea for allergies should be tested first for ragweed, mugwort and echinacea sensitivity," said Frieri. "They can have a life-threatening reaction."
"The plant family that echinacea belongs to is one of the largest and thus [echinacea] has many brothers and sisters that are cross-allergens," said Anthony Almada, president and chief scientific officer, Imaginutrition, based in Laguna Niguel, Calif. "This could sensitize people to echinacea when they are echinacea naive. However, systematic research needs to be undertaken to examine this association more closely."
The echinacea study was based on observed reactions in five patients referred to the researchers for evaluation, and 51 adverse reaction reports submitted to the Australian Adverse Drug Reactions Advisory Committee. They involved at least six different brands of echinacea in the form of tea, tablets and liquid.
The researchers included echinacea in the routine panel of allergens when testing 100 consecutive patients referred for evaluation of asthma or allergic rhinitis. Although only three had taken echinacea previously, 20 percent reacted to skin prick testing with a significant visible, physical flare and raised wheal.
In the five observed cases, patients (including a health professional) reacted within five minutes to two days after they first or subsequently took echinacea. They experienced acute asthma attacks, shock, skin rash lasting up to six weeks, burning throat, chest pains, hives, diarrhea, facial and airway swelling, dizziness and disorientation. One teen had an acute asthma attack 10 minutes after her first exposure to echinacea, taken as a tea.
The researchers interviewed health providers on 51 cases, who determined echinacea was the sole trigger in 41 of those cases. More than 50 percent of the patients had pre-existing asthma or allergy symptoms affecting their eyes, noses or skin.
"This study is provocative and puzzling," Almada said. "The adverse event reports in the United States are far less abundant and do not mirror those described in this [Australian] paper."
"It is important to point out that this study includes only a few cases and this is an herb used by millions of people," McCaleb said.
Additional reporting by NFM staff .
Natural Foods Merchandiser volume XXIII/number 3/p. 32, 38
Natural Foods Merchandiser volume XXIII/number 3/p. 32