Allergy Shots Are Helpful for Some Asthmatics, Risky for Others

By Laura Kennedy, Contributing Writer, Health Behavior News Service

Allergy shots can reduce symptoms of asthma, use of inhaled medications and allergy-related asthma attacks, confirms an updated review of studies. Yet, the treatment can also cause systemic side effects that range from a stuffy nose to fatal anaphylactic shock.


The number of patients experiencing systemic reactions of any severity nears 20 percent, the reviewers say, although they note that more than 8 percent of patients receiving placebo experience similar reactions. Fatalities remain extremely rare at one death per 2.5 million injections.


Immunotherapy is most risky for patients with poorly controlled asthma, said Harold Nelson, M.D., of National Jewish Health, a Denver hospital specializing in respiratory, cardiac, immune and related disorders. Nelson is an international authority on immunotherapy. “People with treatment-resistant asthma are not candidates for allergy shots,” he said. Allergists should also review each patient’s symptoms before every injection, Nelson said. “Patients shouldn’t be actively wheezing, they shouldn’t be waking up at night due to asthma symptoms and their pulmonary function should be relatively normal.” If symptoms are flaring up, doctors should postpone the injection. Professional guidelines recommend that patients remain under observation for 30 to 45 minutes after an injection, so that clinicians can recognize any serious reactions and treat them immediately.


“Among allergists there’s no question that asthma caused by allergies is responsive to immunotherapy,” Nelson said. “The advantage of immunotherapy is that it causes long-lasting, if not permanent, improvement.” Furthermore, most people who have allergy-induced asthma also have nasal symptoms, Nelson said. “They have to inhale steroids into their lungs and spray them into their nose, and a lot of people don’t like to do that forever. Immunotherapy treats both the nasal and chest symptoms.”


The review authors say that allergy drops, which patients place under the tongue, might offer effective asthma control with a reduced risk of serious side effects. While widely used in Europe and the United Kingdom, the U.S. Food and Drug Administration has not yet approved “sublingual immunotherapy.”


“During my training as a respiratory physician, I was taught that this was a potentially dangerous form of therapy that was of no benefit in asthma, Abramson said. “I personally have changed my views since working on this series of reviews.”


Abramson MH, Puy RM, Weiner JM. Injection allergen immunotherapy for asthma. Cochrane Database of Systematic Reviews 2010, Issue 8.


http://www.cfah.org/hbns/archives/getDocument.cfm?documentID=22288