Semi-depot hyposensitization in severe hay fever: its clinical effectiveness and the therapeutic problems. (A four year study using intranasal challenge testing to monitor success).

Hyposensitization treatment for at least two years using pyridine-extracted alum precipitated (PEAP) extracts was carried out on 332 cases of severe hay fever, some of which were steroid dependent. Subjective self-assessment and weekly average use of additional medication were recorded, nasal challenge tests were conducted before and during treatment and related to the clinical picture. Successful treatment was unrelated to age, though distinctly limited where there was a history of more 15 years illness. It was however related to the pollen count from 1973 to 1976 and to the type and number of the antigens to which there was a clinical response. In spite of specific hyposensitization 4,2% of the pollinosis cases developed additional pollen asthma. In the course of treatment there were several instances of an enlargement of the individual antigen spectrum; sensitization to pollen, mould fungi, house dust and animal epithelia were recorded. In a total of 11,850 injections there were severe local reactions in 16,2% rhinoconjunctivitis in 1,6% asthma in 0,4% and urticaria in 0,4%. One female patient went into anaphylactic shock 12 hours after the administration of the antigen extract. In about 20% of the injections granulomas developed, about the size of a cherry-stone, which persisted for up to six months and which in some instances were reactivated by severe exposure to allergens. There was an unusually high percentage of organ and generalised reactions whenever the treatment was continued using a new antigen solution without reducing the dose.