Respiratory allergy to algae: clinical aspects.

A comprehensive investigation was done to evaluate the allergenic algae in the Delhi area. Results of 4,000 skin tests performed on 400 patients suffering from naso-bronchial allergy and 300 skin tests on 30 healthy persons with 10 common algae isolated from the Dehli atmosphere are presented and compared. Positive skin reactions (1+ to 3+) to algae extracts ranged from 25.7% with Lyngbya major extract to 1.7% with Oscillatoria simplicissima extract; in healthy non-allergic volunteers there were no positive skin reactions. The Prausnitz-Küstner (PK), bronchial provocation and conjunctival tests were negative in patients with negative skin reactions; in patients with positive skin reactions PK was positive in 70.9%, bronchial provocation in 50% and conjunctival in 48.5%. Levels of total IgE in patients with naso-bronchial allergy were higher, ranging from 1,225 international units per ml to 1,550 international units per ml, while in healthy volunteers the values were less than 885 international units per ml.