Pollen Allergy

Hayfever is a commonly used term for pollen allergy normally experienced in the temperate regions during spring and early summer when the pollen counts in the air are very high due to the flowering season. Nose allergy is predominant with frequent sneezing bouts accompanied with runny or clogged nose. The nose mucosal membrane, the eye conjunctiva and the throat are very itchy. Moreover, the membrane lining the eyelid become inflamed and cause red-rimmed eyes. The eyes water continuously. Hay fever susceptible individuals are miserable during Spring-Summer period when most people are enjoying the beauty of nature. In Malaysia there is no fixed flowering season but individuals with allergic rhinitis and rhinoconjunctivitis do show reaction to local pollens. Grass pollens account for about 40% of total particle counts in the air in Kuala Lumpur city area and these grass pollen counts reach peak levels during the month of March and September. Allergy tests in asthmatics showed that 22 % reacted to grass pollens and a similar number reacted to tree pollens, specifically Acacia species and oil palm pollens, in the city. On the other hand in Kelantan 18% of patients with perennial rhinitis were positive to grass pollens probably related to rice plant pollens. In one study it was observed that the patients with allergic disease reacted to oil-palm pollen (Elaeis guineensis) with high frequency (22 %), followed by resam-fern spores (34%), sea-teak pollen (34%) and fungal spores (32%). Positive responses to these allergens correlated with total serum IgE levels of the subjects. The grasses most often implicated were Bahia, Bermuda and rough pigweed. Many types of grasses have been introduced into the country for lawns and golf courses and the pollens generated from these grasses may pose a risk factor for some people. These studies, however, clearly demonstrate that pollens from tropical plants, both grasses and trees, play an important role as potential causal factor in allergic rhinitis, allergic conjunctivitis and asthma. In addition, allergenic cross-reactivity has been described for different species of palm pollens. Cross-reacting allergens are present in palm pollens from betel nut, coconut, royal palm, date palm, oil palm and other palms trees. Thus the evaluation of response to pollens should consider aspects of cross-reactivity between related plants in triggering the allergic reaction. Rice pollen allergy is important in parts of the world where rice is cultivated extensively. In Malaysia rice is cultivated in Northern parts of the country particularly some areas of Perak and Selangor, Kedah Perlis and Kelantan. Rice pollen proteins do elicit a specific reaction in asthmatics children and is an important causal factor for allergic rhinitis. Rice pollen allergy should be distinguished from “Rice Millers’ Syndrome” which due to irritant effect from the husk particles.