Background: There are several immunological and clinical effects induced by specific immunotherapy (SIT). A reduction of reactivity to allergen is the final propose of this therapy. The aim of this study was to evaluate the specific cutaneous reactivity, two years after beginning SIT.
Methods: We included 95 patients with bronchial asthma (BA) and/or allergic rhinitis (AR) to house dust mites (HDM). 74 patients were submitted to subcutaneous SIT with commercial extracts of Dermatophagoides. The control group included the 21 patients without SIT. After a two years period, the cutaneous reactivity was reassessed, by skin prick tests (SPT). The effect of SIT in the cutaneous response was evaluated by calculating the difference between the wheal diameter of the SPT before and after treatment. A positive difference indicated a cutaneous reactivity reduction.
Results: The patients submitted to SIT included 52.7% males and 47.3% females, with a mean age of 18.4 +/- 13.9 years old. The cutaneous reactivity to D. pteronyssinus, before and two years after the beginning of SIT, were 6.9 +/- 3 mm and 5.1 +/- 2.9 mm, respectively, with 1.87 of difference (p = 0.0001). The cutaneous reactivity to D. farinae, before and two years after the beginning of SIT, were 6.2 +/- 2.4 mm and 5.0 +/- 3.7 mm, respectively, with 0.93 of difference (p = 0.0790). In the control group, the cutaneous reactivity to D. pteronyssinus was 4.4 +/- 2.1 mm and two years later it was 8.2 +/- 3.7 mm. The difference was -1.53 (p = 0.1590). The cutaneous reactivity to D. farinae was 4.6 +/- 2.2 mm in the first evaluation and 8.3 +/- 4.7 mm two years later. The difference was -2.63 (p = 0.0470).
Conclusions: This study showed a significant reduction of specific cutaneous reactivity induced by Dermatophagoides SIT. In the control group the cutaneous reactivity to Dermatophagoides revealed an increment.