A new study has pointed out that allergy shots which alleviate symptoms of asthma may have side effects.
The side effects could range from a stuffy nose to fatal anaphylactic shock.
The study shows about 30 percent of asthma patients experience improved breathing after receiving a series of injections that desensitize their immune systems to specific irritants.
The number of patients experiencing systemic reactions of any severity nears 20 percent, the reviewers said, although they noted that more than eight percent of patients receiving placebo experience similar reactions.
"Whilst inhaled corticosteroid therapy remains the mainstay of asthma management, any reduction in this type of treatment while maintaining good asthma control would be welcome," the authors wrote.
The review provides evidence to help patients and their doctors have a "sensible discussion" about the benefits versus risks of immunotherapy, said co-author Michael Abramson of Monash University.
Immunotherapy is most risky for patients with poorly controlled asthma and people with treatment-resistant asthma are not candidates for allergy shots," said Harold Nelson of National Jewish Health.
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."
"Among allergists there's no question that asthma caused by allergies is responsive to immunotherapy.
"The advantage of immunotherapy is that it causes long-lasting, if not permanent, improvement," Nelson said.
Abramson described the risk of side effects as "acceptable but definite" for both adults and children.
The review authors said that allergy drops, which patients place under the tongue, might offer effective asthma control with a reduced risk of serious side effects.
"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.
"I personally have changed my views since working on this series of reviews" Abramson said.
The review appeared in the The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates research in all aspects of health care.