Is 2 Years of Allergen Immunotherapy Enough?

More than 15% of the U.S. population has allergic rhinitis, and in many of these patients, rhinitis is not controlled adequately with intranasal steroids and oral antihistamines. Both subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) provide durable symptom control and sustained symptom improvement when they are stopped after 3 years of therapy. Researchers examined whether shorter courses of SLIT or SCIT provide these same benefits.

One hundred six patients in the U.K. with grass pollen–induced allergic rhinitis were randomized to SLIT, SCIT, or placebo for 2 years. SLIT was administered as a daily Timothy grass tablet; SCIT patients underwent weekly allergen buildup for 15 weeks, followed by monthly injections with Timo…