Allergy immunotherapy: Who, what, when … and how safe?
The evidence-based answers to these and other questions will help you to update your knowledge of allergy immunotherapy.
PRACTICE RECOMMENDATIONS
› Diagnose allergies that are amenable to allergy immunotherapy (AIT) using skin prick/puncture allergy testing in conjunction with clinical symptoms, triggers, and exposure. A
› Do not use AIT for urticaria, angioedema, drug hypersensitivity, or latex allergy. A
› Do not initiate AIT during pregnancy or in patients with acquired immune deficiency syndrome or severe asthma. C
Strength of recommendation (SOR)
A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series
Stinging insects. VIT is used for patients with hypersensitivity to the venom from insects of the order Hymenoptera (see previous list of insects).3,11,22 A meta-analysis concluded, based on limited evidence from low-quality studies, that VIT has the potential to substantially reduce the incidence of severe allergic reactions in patients with Hymenoptera sensitivity with 72% of patients benefitting from VIT (number needed to treat [NNT] = 1.4).22 VIT reduces the risk of a systemic reaction, as well as the size and duration of large local reactions (LLRs).6,22 Immunotherapy for stinging insects also has been shown to improve disease-specific quality of life (risk difference = 1.41 strongly favoring VIT).6,22
Insect allergens. Research has shown AIT to be an effective therapy for many allergens even though the potency and effectiveness for some allergens are not standardized or regulated.6,7,11,14 For example, AIT is available for some inhaled insect allergens; however, because the extracts are not standardized, AIT produces inconsistent outcomes.11,14 As another example, certain occupations lead to exposure to inhaled insect allergens such as silkworm and weevils. AIT is not indicated for either because available silkworm extracts are used only for allergy testing.11 There are no extracts to test for or treat weevil allergy.11
Food. IgE-mediated food allergy can result in oral allergy syndrome, angioedema, urticaria, and/or anaphylaxis.2,7,8 There is some evidence that AIT raises the threshold of reactivity in children with IgE-mediated food allergies.6,7,23-25 But the studies available for meta-analyses (some of which involved OIT) were deemed to be of low quality due to a high risk of bias and a small number of participants.24,25 AIT for food allergies is associated with a substantially increased incidence of moderate adverse reactions, including upper respiratory, gastrointestinal, and skin symptoms, with a probability of 46% during the buildup phase and a number needed to harm (NNH) of 2.1 (95% CI, 1.8-2.5; P < .0001).6,25 Therefore, experts consider AIT in any form for food hypersensitivity to be investigational.6,10
But preliminary data from a recent phase 3 trial of OIT for peanut allergy involving 499 children and teens are promising; 67.2% tolerated the food challenge of ≥ 600 mg of peanut protein at the completion of peanut OIT without dose-limiting symptoms (difference = 63.2 percentage points; 95% CI, 53-73.3; P < .001).26 More than twice as many participants in the placebo group vs the treatment group experienced AEs that were moderate (59% vs 25%, respectively) or severe (11% vs 5%, respectively).
There are ongoing trials of SCIT, SLIT, and OIT using modified food allergens to make participants less allergic while maintaining immunogenicity.2,27 Additional trials include adjunctive treatments like probiotics to create safer, more effective options for children with food allergies.2,27 Keep in mind that children with food allergies often have concomitant allergies (eg, inhalant allergies) that can benefit from AIT.
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