Sublingual Immunotherapy Research Packs a Powerful Punch

It was roughly 100 years ago that clinicians began to discover the effectiveness of sublingual (under-the-tongue) immunotherapy for allergies. It’s hard to discount the growing body of research in favor of sublingual immunotherapy (SLIT) which involves dispensing antigen under the tongue (rather than injecting
it into the skin).

Hundreds of peer-reviewed studies have established SLIT’s effectiveness in the past 20 years alone. In fact, a 2007 paper published by the multi-nation ARIA collaboration (Allergy Rhinitis and its Impact on Asthma) showed that not only is there more current research on sublingual immunotherapy (as comparedto allergy shots or SCIT), but according to the World Health Organization, the SLIT studies are also of a higher quality than allergy shot (SCIT) studies.  Furthermore, the Cochrane Review (the most credible, evidence-based meta-analysis entity worldwide) identified sublingual immunotherapy as both safe and efficacious in their 2003 report.

Key research includes a 2003 study1 published in Clinical and Experimental Allergy that affirmed the effectiveness of sublingual immunotherapy in children with dust mite allergy over a 10-year period. Additionally, a landmark 2004 placebo-controlled, double-blind, double-dummy study2 published in Allergy brought SLIT and SCIT head to head and found SLIT to demonstrate comparable clinical efficacy. The only studies (and they are few) that question the efficacy of SLIT are significantly dated or have since been called into question.

Shots are still prescribed more commonly in America but not so in other parts of the world such as Europe where, in some countries, sublingual immunotherapy is at least as commonly prescribed as shots. More and more U.S. allergy physicians and researchers are pressing for full governmental and regulatory recognition of SLIT in the U.S. with plenty of indisputable evidence to help make their case. And as Americans’ appetite for a safer, less time-consuming treatment than allergy shots increases, SLIT is looking more and more attractive.


1 Di Rienzo V, Canonica GW, Passalacqua G. Long-lasting effect of sublingual immunotherapy in children with asthma due to house dust mite: a 10 year
prospective study. Clinical and Experimental Allergy. 2003;33:206-210.

2 Khinchi M. Clinical efficacy of sublingual and subcutaneous birch pollen allergen-specific immunotherapy:A randomized, placebo-controlled, double-blind,
double-dummy study. Allergy. 2004;59:45-53.

About The Author

Stuart H. Agren, M.D.

Stuart H. Agren, M.D. completed his undergraduate studies at the University of Utah and went on to earn his Doctor of Medicine from Tulane University School of Medicine in 1974. He completed additional training at L.D.S. Hospital in Salt Lake City, Utah and then established his private medical practice starting in 1975. Dr. Agren completed a mini-residency in Industrial Medicine at the Robert Johnson School of Medicine at Rutgers University and also completed training to become a certified Medical Review Officer.

Dr. Agren was the Medical Director at TRW and McDonnell Douglas in Mesa, Arizona and at Stauffer Chemical and Kennecott Copper in Salt Lake City, Utah. He also served as an adjunct faculty member at Arizona State University.

In his private medical practice, Dr. Agren specialized in family practice and allergy. In his work as a private practice allergist, he was one of the first doctors in the country to prescribe sublingual immunotherapy to his patients as an alternative to subcutaneous immunotherapy (allergy shots). He has also been a trailblazer in the field of food allergy treatment and research, developing a program to treat multiple food allergies simultaneously using sublingual immunotherapy. Dr. Agren has been featured on local CBS, NBC, and ABC news affiliates and won the peer-nominated “Top Doc” award from Phoenix Magazine.

After 20 years in private practice, Dr. Agren became the Founder and President of AllergyEasy, which helps primary care physicians around the country offer allergy testing and sublingual immunotherapy treatment to their patients. Over 200 physicians in over 32 states use the AllergyEasy program to help their patients overcome environmental and food allergies and asthma.