[Perennial allergic rhinitis: stepwise regression analysis on the correlation with the efficacy of allergen-specific...

To investigate the correlation factors of the immunotherapeutic efficiency of perennial allergic rhinitis (PAR).

One hundred and sixty-four patients with PAR were treated with specific immunotherapy (IT) in our department between 1990 and 2000. Specific allergens were selected through the history and skin test or nasal provocation test. The patients were given subcutaneous injections with allergen extract which was produced by Xiehe Hospital. The individual initiative dose was determined by the skin test reaction or the end point concentration. The doses were gradually increased until the maintenance dose (10(2) w/v, 0.5 ml once time), then the interval between injections was gradually increased up to one month. The clinical effectiveness evaluation based on the symptoms and signs before and after IT was judged as marked, moderated and poor response. The possible factors which affected the efficacy of IT were selected. These factors included sex, age, illness duration, disease condition, asthma, duration of IT, reaction condition of the skin test, accompanying itch of eye, ear and oral cavity, eosinophilia in nasal smears and family history of atopy. The correlation factors with efficacy were sifted with multifactorial stepwise regression analysis.

The marked, moderated and poor response were 14.4%, 54.3% and 31.3% respectively. The efficacy of IT correlated well with the duration of IT (P < 0.01), but not with sex, illness duration, disease condition, reaction condition of the skin test, accompanying itch of eye, ear and oral cavity, eosinophilia in nasal smears and family history of atopy. Asthma and age maybe influenced the effect of IT (P = 0.081, P = 0.063).

This study demonstrates that the immunotherapy is effective in the treatment of perennial allergic rhinitis. The duration is the factor significantly influences the efficacy of IT. The efficacy of long-IT was superior to that of the short-IT.