Allergy shots for dust mite allergy – how long is long enough?
Specific immunotherapy (SIT) has long been known as an effective way to reduce both asthma and rhinitis (hayfever) symptoms that are caused by inhaled allergens such as pollens and dust mites. However, the duration of treatment with these allergy shots is decided on a case-by-case basis, and there has not yet been research specifically designed to determine an optimal length of time that SIT should be given to patients. This information could have an influence in patients’ compliance with therapy, managing the costs of treatment, and achieving optimal effectiveness.
In a study published in the January 2011 issue of The Journal of Allergy and Clinical Immunology (JACI), Tabar et al examined the differences of efficacy of house dust mite (HDM) SIT for respiratory allergy for varying lengths of time. Patients with respiratory allergy due to dust mites were enrolled in the study and after 3 years of SIT, half of them stopped the allergy shots and the other half continued receiving SIT for another 2 years. A control group of dust mite-allergic patients receiving only drug therapy for symptoms was also part of the study. The effectiveness of treatment was measured with symptom severity scores, medication use, patient assessment of quality of life and for patients with asthma, lung function testing.
The authors found that after three years of SIT, patients showed improvement in rhinitis and asthma symptoms, and that the benefit continued in following years. Patients who received SIT for a five-year period showed an additional decrease in rhinitis symptoms.
Among all patients in the study who received SIT, 70% remained asthma-free after SIT, even those who stopped SIT after 3 years. The authors’ findings suggest that 3 years may be an adequate duration period for SIT in the treatment of house dust mite allergy and that clinical benefits of SIT continue even two years after SIT is discontinued. A longer observation period of these patients could determine if a five-year course of SIT would lead to a more prolonged effectiveness.
The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.