I was recently embroiled in an online discussion with several pulmonary and primary care colleagues regarding the efficacy of Allergen Immunotherapy in the treatment of asthma and the future of sublingual immunotherapy, which I think is worth sharing. Let’s start off with some Frequently Asked Questions:
Whare are “Allergy Shots”?
Allergen immunotherapy or “allergy shots” is a form of treatment aimed at decreasing sensitivity to substances called allergens which were identified by allergy testing. Allergen immunotherapy involves injecting increasing amounts of these allergens to a patient over a period of time to decrease the patient’s sensitivity to the allergens, prevent development of new allergies, and in children, prevent progression from allergic rhinitis to asthma. Allergen immunotherapy can lead to long-lasting relief of allergy symptoms after treatment is discontinued.
How does Allergen Immunotherapy work?
Allergen immunotherapy works like a vaccine. Your body responds to injected amounts of a specific allergen by developing immunity or tolerance. There are two phases to immunotherapy: a build-up phase and a maintenance phase.
When will the allergy shots start working and when can I stop my meds?
The benefits of allergen immunotherapy, in terms of reduced allergy symptoms, can begin during the build-up phase but may take as long as 12 months on the maintenance doses. It is important to continue taking allergy medications as prescribed together with the allergy shots during the build-up phase. Later, when your symptoms improve, you may discuss with your doctor whether you can discontinue some of your allergy medications.
If you do not get your allergy shots on schedule, it will take longer to reach the maintenance dose and longer for the allergy shots to work effectively.
How long do I have to take the Allergy shots?
With currently available allergen extracts, maintenance treatment is generally continued for 3 to 5 years after the build-up phase, which can take up to 6 to 9 months. The majority of inidividuals experience lasting remission but a minority may relapse after discontinuing immunotherapy, therefore the decision to stop must be individualized.
How effective is allergen immunotherapy?
Immunotherapy is successful in up to 90-95% of patients with seasonal allergies and up to 85% of patients with year-round allergies.
Asthma is a multifactorial disease. Allergic rhinitis/ sinusitis has definitively been shown to contribute to the severity of asthma in patients. One of the modalities used to treat allergic rhinitis/ sinusitis and asthma is allergen immunotherapy (IT). By no means is anyone suggesting that allergen immunotherapy be used INSTEAD OF inhaled steroids, however allergen IT does have solid data to show its efficacy when used in conjunction with other modalities.
This is topic has been addressed by the American College of Allergy, Asthma, and Immunology in its position paper on the Cost Effectiveness of Immunotherapy for Asthma.
Regarding sublingual immunotherapy, there is considerable evidence that sublingual immunotherapy for allergic rhino-conjunctivitis has been effective using high doses of grass extract. This is commercially available and used in Europe, but has yet to have FDA approval in the USA. Some studies showing efficacy are cited below:
1. Calderon M, Essendrop M. Specific immunotherapy with high dose SO standardized grass allergen tablets was safe and well tolerated. J Investig Allergol Clin Immunol. 2006;16(6):338-44. 2. Nelson HS. Advances in upper airway diseases and allergen immunotherapy. J Allergy Clin Immunol. 2007 Feb 8; [Epub ahead of print]
That being said, appropriate dosing and efficacy with multiple SL allergen combinations are still an issue.
The “sublingual immunotherapy” that is pure quackery has been used to treat “idiopathic environmental intolerance” (IEI) by means of “neutralizing” extracts administered as sublingual drops usually at such a miniscule dose that it is really only placebo. See the AAAAI position statement on this.
For a tragic example of the use of these “neutralizing sublingual drops” for treatment of IEI or “multiple chemical sensitivity syndrome” see the “Tragic Example” post on this blog.