The mountain cedar model in clinical trials of seasonal allergic rhinoconjunctivitis

Background: Clinical trials of seasonal allergic rhinoconjunctivitis use the mountain cedar (Juniperus ashei) season as the predominate model. Objective: To evaluate clinical trials of rhinoconjunctivitis using mountain cedar, to present analysis of pollen counts during 18 seasons, and to discuss the model. Methods: The medical literature was searched for clinical trials performed using mountain cedar either in or out of season. Pollen counts were recorded and analyzed for the duration of 18 seasons. Results: Thirty-eight trials were identified. Of these, 1 evaluated onset of allergy, 8 were immunotherapy trials, 28 were pharmaceutical clinical trials, and 1 studied symptoms elicited in a pollen challenge chamber trial. Many generic equivalency trials are unreported. In the 18 years of counts in the Texas Hill Country, a dependable and intense pollen density was present in every season. The combination of dependable seasons without confounding pollens, the large number of allergic patients, and the ability to concentrate resources in one geographic area has made mountain cedar allergy a mainstay for therapeutic trials for allergic rhinoconjunctivitis. Conclusion: Mountain cedar allergy presents a dependable and durable model of allergic rhinoconjunctivitis.