Respiratory Allergy to Conifers

The conifers, from the latin meaning “cone carrier,” include about 650 species distributed in seven families. They are found all over the world, and the most known conifers are the cypresses, the junipers, the yews, the larches, the firs, or the pines. The most allergenic pollen is emitted by the Cupressaceae/Taxaceae family with mainly five different genera: Cupressus, Hesperocyparis, Juniperus, Cryptomeria, and Chamaecyparis. The symptomatic period starts in November and ends in April. In Mediterranean areas, Cupressus sempervirens is the most common pollinating species. Five main cypress allergens have been thoroughly described. Depending on the geographic area and the studied population, the prevalence of cypress allergy in the general population ranges from 0.6% to 3%, and 9–65% of outpatients consulting an allergist are sensitized to cypress pollen. This prevalence is increasing likely to be due to the modifications of the environment. Rhinitis is the most prevalent clinical symptom, while conjunctivitis is the most disabling. Clear-cut improvements of the quality of life are observed upon an effective and safe specific immunotherapy. Associations with food allergy based on molecular allergen cross-reactivities were described resulting in sometimes severe symptoms. Pollens from Pinaceae family, especially pines or firs, although abundant, do not demonstrate a significant clinical impact.