You may have heard about allergen immunotherapy and why it can be helpful in the treatment and control of allergies and allergic asthma. Most people in the United States think of allergy shots when they hear the term immunotherapy. But people with asthma who live in Europe often think of allergy drops, rather than shots, when they hear the term immunotherapy.
So, what's the difference between allergy shots and allergy drops? Is one better than the other?
Immunotherapy can be given either by injection, usually into the arm, or by mouth, either in liquid or tablet form, which is placed under the tongue and allowed to dissolve naturally. The more correct name for allergy drops is "sublingual immunotherapy", or SLIT for short. (Sublingual means "under the tongue.")
What Is Different
There are some significant differences between allergy shots and allergy drops.
- Allergy shots are approved by the FDA in the United States, while SLIT is not yet, though it may still be available from certain doctors. Still, SLIT may be harder to obtain than allergy shots for now. Your safest course is to talk with an allergist, no matter which type of immunotherapy you want to explore.
- Allergy shots can be used to desensitize you for any number of allergy and asthma triggers at once. SLIT has mostly been used to desensitize for one allergen at a time, so it is not yet known if it can be used with multiple allergens.
- A lot of scientific evidence proves the effectiveness of allergy shots. But, not enough scientific studies with SLIT have been done to be sure it has the same effectiveness. The studies that do exist, however, suggest it is effective.
- SLIT can be started at a higher maintenance dose than allergy shots, so desensitization can occur more quickly. At the same time, SLIT is less invasive and seems to have less potential side effects.
- Allergy shots can hurt (at least a little) and must be given in a doctor's office, while SLIT can be taken at home on your own, once started. So, SLIT may seem both more comfortable and convenient.
- Allergy shots are generally covered by health insurance, while SLIT is not, since it is not yet an FDA-approved therapy for allergies and asthma. However, for people who don't have health insurance, SLIT may be less costly as it can be self-administered, rather than requiring a specialty healthcare professional.
Sources:
Frew, Anthony J. MD. "Sublingual Immunotherapy." NEJM. 358:21 2008. <http://content.nejm.org/cgi/content/full/358/21/2259> Goldstein S. Immunotherapy: decreasing sensitivity to allergy symptoms.Allergy & Asthma Advocate Spring 2004: 1-2. http://www.aaaai.org/patients/advocate/2004/spring/immunotherapy.stm. Accessed 12/7/2006. American College of Allergy, Asthma & Immunology. End allergy and asthma misery: it's worth a shot. http://www.acaai.org/Member/Practice_Resources/allergicasthmaslides.htm. Accessed 12/7/06. Abramson MJ, Puy RM, Weiner JM. Allergen immunotherapy for asthma. The Cochrane Database of Systematic Reviews 2006 Issue 4 (Abstract). http://www.cochrane.org/reviews/en/ab001186.html
