ABSTRACT
Introduction Immunotherapy began in the early 1900s and was first applied to allergic rhinitis. In 1911, Noon prepared pollen extracts based on the weight of the pollen and he administered these extracts subcutaneously at 1-2 week intervals. He observed that patients receiving injections of grass pollen extract had diminished ocular allergen challenge reactions. The response to the administration of these allergens was dose dependent, but large doses of allergen extracts could provoke a systemic reaction.
