Increase of respiratory allergy to the pollens of cypresses in the south of France.

A form of pollen allergy, which is uncommon in most parts of the world and in other Mediterranean countries where cypresses are abundant (Italy, Spain, Greece), with the exception of Israel, has become a problem since 1975 in our area. We have found 111 cases since 1975 compared with only a few cases from 1950 to 1975. The period of pollination is between mid-February and the end of March. Diagnosis has been made by skin tests and, in some instances, by RAST with good correlation. In almost all the cases, cross-reactivity has been found between the members of the Cupressaceae family with Cupressus sempervirens, the commonest cypress in the South of France, associated most often with this allergy. Clinically, allergy was of the oculo-nasal type with the association, in a few cases, of asthma or spasmodic cough. The unexpected increase of a particular allergy in a given population of atopic people raises several general problems. In this particular case it seems to us that the larger number of cypresses, which have been recently grown, is not the only explanation of the phenomenon.