30 Ragweed Allergy – What Role Does It Play in Bavaria?

BACKGROUND: Ragweed (Ambrosia artemisiifolia), is increasingly spreading in Southern Germany and Central Europe. Little is yet known about the sensitization and allergy rates in Bavaria. METHODS: In 2008 to 2010 patients from a Bavarian university allergy unit were enrolled into the study. The patient's history was recorded by a standardised questionnaire concerning allergies. Sensitization rates were measured by skin prick test (SPT) for seasonal aeroallergens including ragweed. Patients sensitized to ragweed were further characterized by measuring specific serum immunoglobulin E (IgE) for ragweed specific allergens (by ImmunoCAP and ELISA). To determine the clinical relevance challenge tests (nasal/conjunctival) with ragweed were performed. RESULTS: 1022 patients were enrolled in the study (665 female, 357 male). 289 patients were sensitized to ragweed (SPT positive). In ragweed sensitized patients the sensitization rate to mugwort was 61.8% whilst in patients not sensitized to ragweed it was 7.4%. The sensitization to birch was 78.1% resp. 36.4%. In 120 ragweed sensitized patients challenge tests with ragweed extract were performed (nasal n = 110; conjunctival n = 60) with positive results in 29 (26%) resp. 12 (20%) patients. In 232 ragweed sensitized patients specific IgE to nArt v 1 was observed significantly more frequently than to nAmb a 1. CONCLUSIONS: The results of this 3-year study show that in a Bavarian allergy unit sensitization to ragweed is frequent. Often ragweed-sensitized patients have sensitivities to multiple seasonal aeroallergens. There is a coexistence of ragweed and mugwort specific allergens. One fourth of the challenged patients that are sensitized to ragweed show clinical allergy symptoms. With sufficient ambient allergen exposure, a prolonged allergy season can be expected for this at-risk population.