The safety of allergen immunotherapy: a literature review

Allergen immunotherapy is a safe form of therapy with a very low incidence of systemic allergic reactions and fatalities. Over the past few years, as a result of several investigations, risk factors have been identified, although some disagreement remains. Asthmatics, patients on beta-blockers and highly sensitive patients are groups at increased risk for systemic reactions. Reactions are more common among individuals receiving extracts of pollens, particularly grass and ragweed. Most authors have also reported that reactions are more common in season. Chest tightness or wheezing, urticaria, pruritus and throat congestion were frequent symptoms of severe systemic reactions. The recommendations of Greenburg et al (Table 1) and Davis et al (Table 2) serve as valuable guidelines. Otolaryngologic allergists have found that home maintenance immunotherapy is a safe treatment option (in low-risk patients). In any case, immunotherapy should be supervised by a physician well trained in its use and indications, and should be administered by personnel trained in the treatment of medical emergencies, specifically those related to allergy. This training should include cardiac resuscitation. In addition, consideration should be given to premedicating patients with antihistamines or corticosteroids and to measuring peak flows prior to injection. Because asthmatics are a very high-risk group, it is recommended that these patients not undergo immunotherapy at home. In patients who have had multiple reactions or in those with severe asthma, consideration should be given to discontinuing injections. Finally, optimal or moderate allergen dosing may provide the needed balance between therapeutic efficacy and safety.