Frequency of ragweed sensitization and allergy among patients with respiratory allergy.

Pollen is well known to cause seasonal allergy. Ragweed sensitization and allergy represent a worldwide challenge for allergists. Ambrosia is one of the major genera in the Asteraceae family which includes at least 51 species known as "ragweed". The current study aimed at determining frequency of ragweed sensitization and allergy among patients with respiratory allergy. The study included 220 subjects selected from patients attended the Allergy Clinic, Ain Shams University. All patients were subjected to detailed medical history, clinical examination, asthma severity grading according to the Global Initiative for Asthma (GINA) guidelines, allergic rhinitis severity grading according to the allergic rhinitis and its impact on asthma (ARIA) guidelines, pulmonary function tests for asthmatic patients, complete blood count with differential for detection of eosinophilia, serum total IgE and skin prick testing (SPT) to ragweed pollen together with common inhalants and common food allergens. Specific IgE for Ambrosia artemisiifolia was done for patients who showed positive SPT to ragweed pollen. About 34% of patients had positive SPT to ragweed, 30.5% were sensitized to ragweed and 3.2% allergic. Specific IgE for A. artemisiifolia was positive in 33.8%. There was a statistically significant association between ragweed sensitization and level of asthma control and disease duration. We concluded that ragweed sensitization is less common as the frequency of Ambrosia pollen sensitization was about one third of the studied allergic patients.