Insufficient data according to the CIR panel
Expert assessmentCIR panel 2001Arnica montana and its extract
About 100 cosmetic formulas contained the extract. Clinical tests showed neither irritation nor sensitization, but a delayed allergy (type IV) is described in people who handle the flowers. For lack of sufficient data, the panel does not conclude. Ingesting arnica has caused serious poisonings2.
1.13% of people sensitized to arnica in a test series
Clinical trial443 consecutive people testedCompositae mix, lactone mix, arnica, calendula
5 people (about 1.13%) reacted to arnica, 9 (2.03%) to calendula. The Compositae mix was positive in 3 of the 5 people sensitized to arnica: it is not enough to detect this allergy. The authors recommend testing with plant extracts5.
People sensitized to arnica react to arnica products
Case series6 people sensitized to arnicaTests with arnica products
5 of 6 reacted to arnica-based products. The authors advise against topical use of Asteraceae-based cosmetics by people allergic to this family4.
Among the Asteraceae, arnica is one of the most sensitizing
Review2002 reviewAsteraceae (Compositae)
Of at least 15 suspected species, only arnica and German chamomile have epidemiological data. Sensitization seems relatively common with arnica and elecampane, rare with German chamomile. Sesquiterpene lactones are the main allergens3.
A measurable allergen, used in screening tests
LaboratoryCompositae screening mixArnica, tansy, yarrow, chamomile, feverfew
The extracts of this mix, including arnica, have a variable sesquiterpene lactone content. A spectrophotometric measurement method matches the clinical results well and is used for quality control of extracts with allergenic potential7.
In mice, arnica allergy appears only without immune defenses
LaboratoryMouse contact hypersensitivity modelArnica tinctures and lactones
In immunocompetent mice, contact hypersensitivity to arnica could not be induced, even with a pure tincture applied to inflamed skin. In mice lacking CD4 lymphocytes and MHC II molecules, it appears. Animal model result, not transferable to humans6.