Exposure to Parthenium hysterophorous pollen extract leads to bronchospasm in stable patients of bronchial asthma.

Role of Parthenium hysterophorous as an allergen evoking bronchial hyper-responsiveness was assessed in twenty five adult patients with stable asthma and ten healthy controls. Assessment was made with the help of skin prick and bronchial provocation tests (BPT) using a commercially available Pathenium extract. Eleven patients (44%) of the study group had a positive skin reaction and 4 (16%) showed a significant fall in FEV1 and PEFR (p < 0.05) on bronchial provocation. In the control group only one patient (10%) had a positive skin test while there was none with a positive bronchial challenge. There was a significant fall in the mean values of FEV1 and PEFR over base line after the BPT in patients of asthma than controls. It is concluded that a significant proportion of bronchial asthma patients are sensitized to Parthenium hysterophorous and it may act as a cofactor in seasonal exacerbation of their symptoms.