[Type I hypersensitivity to gramineae pollen (by species) in allergic rhinitis patients].

A total of 184 Costa Rican Allergic Rhinitis patients with at least one positive skin prick test in a previous study were tested for reaction to Poaceae tribes and species compared with 100 non atopic subjects. Skin prick tests were applied for the most abundant species present in Costa Rica. Highest positivity rates among the Allergic Rhinitis patients were obtained with Anthoxatum odoratum (83.2%) (Tribe Aveneae), Panicum maximum (82.1%) (Paniceae), Panicum mole (78.3%) (Paniceae) and Holcus lanatus (77.7%) (Aveneae). The only species with a low percentage of positivity was Uniola pittieri. There was a high prevalence of positive prick tests to pollens of the Poaceae species used for food, including corn, sorghum, sugar cane and rice. All exceeded 60% of positive results in the patients (against 2% in controls). These cultivated species have a special pattern of flowering which can explain the known exhacerbation of allergic symptoms in patients with perennial allergic rhinitis.