People with asthma and allergies often have to take medication to stop their sneezing, itchy eyes and running noses. There’s new evidence to suggest an allergy treatment used in Europe could help prevent these reactions before they start.
Researchers reviewed 63 studies that looked at the safety and effectiveness of an under-the-tongue allergy treatment.
Results showed moderate overall improvements in allergy and asthma symptoms for study participants who received the treatment.
Sandra Y. Lin, M.D., of the Johns Hopkins University School of Medicine, Baltimore, and colleagues led the study to find out how safe and effective sublingual immunotherapy could be to treat allergy and asthma symptoms.
Sublingual immunotherapy is a type of allergy treatment in which doctors put drops of liquid under the tongue of allergy patients.
Inside this liquid are small amounts of the substances that cause the patients to have allergic reactions. With this small exposure, over time, some patients can reduce their allergic reactions.
To carry out the study, the researchers looked at 63 previous studies on sublingual immunotherapy that included a total of 5,131 participants.
Participants ranged in age from 4 to 74 years old.
The study results showed moderate evidence that sublingual immunotherapy reduced participants’ symptoms, though results varied depending on what they were testing for.
There was strong evidence that sublingual immunotherapy helped reduce asthma symptoms. Eight of the 13 studies that looked at asthma showed that the therapy led to a greater than 40 percent improvement when compared to no sublingual treatment.
Rhinitis and rhinoconjunctivitis, or running nose and itchy eyes, were also moderately improved. According to nine of the 36 studies that looked at these symptoms, participants experienced a 40 percent improvement after the sublingual immunotherapy treatment compared to those who didn’t receive it.
Moderate grade evidence showed that people receiving the study treatment used less medicine. In 16 of the 41 studies, medication use for asthma and allergies decreased by more than 40 percent after participants received sublingual immunotherapy.
Moderate evidence also demonstrated that sublingual immunotherapy had other effects. In 13 of the studies, symptoms of conjunctivitis – or red, itchy eyes – improved.
In 20 of the studies, there was evidence that there were both improvements in symptoms and reductions in medications participants needed to take.
Eight studies showed that participants’ quality of life in terms of their allergies had improved with the study treatment.
The review of these studies also indicated that the results for sublingual immunotherapy were the same for both adults and children with hay fever and asthma symptoms.
Minor reactions to the study treatment were frequent but there were no severe or life-threatening reactions in any of the participants. Similarly, no deaths were reported.
“Our review found moderate strength in the evidence to support the use of sublingual immunotherapy for allergic rhinitis and asthma,” the authors wrote.
“This indicates moderate confidence that the evidence reflects a true efficacy,” they wrote.
The authors concluded that more research is needed to determine what the best dosage would be for this type of treatment.
The study was published March 26 in JAMA. The research was funded by the Agency for Healthcare Research and Quality. Lead author Dr. Lin reported serving as a consultant for Wellpoint. No other authors reported potential conflicts of interest.