Positive Health Online

Abstract

DE LA TORRE and colleagues, Hospital Nuestra Senora de la Candelaria, Tenerife, Canary Islands, Spain, ftorre@comtf.es, investigated possible cross-reactivity in vivo between the known allergens Artemisia vulgaris (a common weed in Tenerife, Canary Islands, Spain) and Matricaria chamomilla – i.e. whether exposure to one allergen can lead to an allergic reaction on exposure to the other – in individuals with asthma and/or rhinitis ('hayfever') .

Background

There have been indications that there may be cross-reactivity between common subtropical weed A. vulgaris and several other plant allergens including those derived from hazelnut, kiwi, birch, several Compositae (Ambrosia, Chrysanthemum, Matricaria and Solidago) and grass allergens. Existing data on in vivo cross-reactivity between A. vulgaris and M. chamomilla are limited. The researchers sought to investigate this phenomenon in sufferers of asthma and/or hayfever.

Methodology

Subjects were 24 individuals with asthma and/or rhinitis sensitized primarily to A. vulgaris . [However, skin prick tests with M. chamomilla were positive in 21 subjects .] Subjects received conjunctival challenges (by drops into the eye) and bronchial challenges (by inhaling) with A. vulgaris and M. chamomilla pollen extracts, and oral challenge with chamomile (by oral administration of a commercial chamomile infusion).

Results

In the conjunctival tests, 18 subjects had a positive response to A. vulgaris and 13 had a positive response to M. chamomilla . In the bronchial tests, 15 had a positive response to A. vulgaris and 16 had a positive response to M. chamomilla . With the oral test, 13 subjects had a positive response to the chamomile infusion . 9 subjects were also found to have positive skin prick tests to food allergens and 17 had positive skin prick tests to other pollens of the Compositae family.

Conclusion

The authors concluded that there is a high degree of in vivo cross-reactivity between A. vulgaris and M. chamomilla . Individuals sensitized to A. vulgaris are likely to be at risk of experiencing allergic symptoms if they ingest chamomile infusions . The results of the study also indicate that M. chamomilla may be an important respiratory allergen .

References

de la Torre MF et al. Clinical cross-reactivity between Artemisia vulgaris and Matricaria chamomilla (chamomile). Journal of Investigative Allergology and Clinical Immunology 11 (2): 118-22. 2001.