Subcutaneous venom immunotherapy in children: Efficacy and safety

Hymenoptera venom allergy in children and adolescents

PURPOSE OF REVIEW

This review will identify and summarize the published existing data pertaining specifically to Hymenoptera venom allergy in children and adolescents, highlighting the major studies currently available on venom immunotherapy (VIT) and its prognosis in children.

RECENT FINDINGS

The current review covers the incidence and prevalence of Hymenoptera venom allergy (HVA) in children, factors influencing occurrence and severity of reactions (age, sex, comorbidities, etc.), indications to perform diagnostic tests and start VIT in children, different existing VIT protocols and their safety and efficacy.

SUMMARY

Hymenoptera venom allergy is the second most common cause of anaphylaxis in children and it considerably affects quality of life. Cutaneous reactions are the most prevalent clinical presentation in children who usually have a more favourable prognosis than adult patients. However, studies on HVA in children and adolescents are still limited. Currently VIT is the only treatment able to modify the natural history of HVA in adults as well as in children, and to protect patients from systemic reactions after subsequent stings.

Updates and Recent Advances on Venom Immunotherapy

Purpose of Review

Venom immunotherapy has been utilized to treat Hymenoptera venom allergy since the 1920s. Over the last century, significant advances in the fields of immunology and genetics have led to improvements in the practice of venom immunotherapy. This review encompasses recent advances in the use of venom immunotherapy to provide precise, patient-centered care.

Recent Findings

Research about the mechanism of action of venom immunotherapy continues to highlight the modification of both the innate and adaptive immune systems. Molecular techniques have allowed for the identification of specific venom allergens to improve the diagnostic accuracy and safety of venom immunotherapy. Research continues to support the safety of accelerated schedules which can impact the cost, adherence, and quality of life for patients receiving this treatment modality. Finally, significant advances have led to the elucidation of risk factors that place patients at risk for reactions during and after venom immunotherapy. Creation of risk profiles for venom-allergic patients can thus inform the process of immunotherapy in order to provide personalized and precise care.

Summary

Significant progress in the use of venom immunotherapy makes the practice a dynamic and active field for continued research. Future research needs to build on these recent advances to continue to optimize and enhance this life-saving treatment.

Adverse Events Associated with the Clinical Use of Bee Venom: A Review

Bee venom is used to treat various diseases but can cause a tickling sensation and anaphylaxis during clinical treatment. Adverse events (AEs) associated with bee venom may vary depending on the dosage, method, route of administration, and the country, region, and user. We summarized the AEs of bee venom used in various ways, such as by the injection of extracts, venom immunotherapy (VIT), live bee stings, or external preparations. We conducted a search in eight databases up to 28 February 2022. It took one month to set the topic and about 2 weeks to set the search terms and the search formula. We conducted a search in advance on 21 February to see if there were omissions in the search terms and whether the search formula was correct. There were no restrictions on the language or bee venom method used and diseases treated. However, natural stings that were not used for treatment were excluded. A total of 105 studies were selected, of which 67, 26, 8, and 4 were on the injection of extracts, VIT, live bee stings, and external preparation, respectively. Sixty-three studies accurately described AEs, while 42 did not report AEs. Thirty-five randomized controlled trials (RCTs) were evaluated for the risk of bias, and most of the studies had low significance. A large-scale clinical RCT that evaluates results based on objective criteria is needed. Strict criteria are needed for the reporting of AEs associated with bee venom

Anaphylactic reactions in the build-up phase of rush immunotherapy for bee venom allergy in pediatric patients: a single-center experience

Background

Anaphylaxis occurs in up to 3.5% of hymenoptera stings and can be a life-threatening emergency. Venom immunotherapy (VIT) provides excellent protection from further episodes of anaphylaxis and is well tolerated. In this study the frequency of anaphylactic reactions in pediatric patients undergoing rush bee venom immunotherapy was assessed as well as possible risk factors and modified up-dosing schemes are reported.

Methods

19 consecutive pediatric patients, who had previously experienced an anaphylactic reaction following a bee sting and showed IgE-mediated sensitization to bee venom, underwent inpatient rush immunotherapy with bee venom extract. We retrospectively compared serological findings (total IgE, serum tryptase level, sensitization to Api m1, Api m3 and Api m10 bee venom allergens) and possible risk factors between patients who experienced an anaphylactic reaction during immunotherapy and patients who did not.

Results

Three of the included 19 patients (15.8%) developed anaphylactic reactions to rush bee venom immunotherapy, all of them between administration of 40 and 80 µg of bee venom extract. However, all three patients reached the standard maintenance dose of 100 µg of bee venom following a modified VIT schedule without any further complications. Total serum IgE levels as well as Api m3 sensitization levels were significantly higher in patients showing an adverse reaction to bee VIT compared to those who did not experience any complications. There were no statistically significant differences concerning age, pre-existing conditions, type and severity of the initial reaction and Api m1, Api m10 and serum tryptase levels between the two subgroups.

Conclusion

Even if anaphylactic reactions occur during the build-up phase of VIT for bee venom in children and adolescents, venom immunotherapy can and should be continued in most cases.

Allergen Immunotherapy in Young Children

PURPOSE OF REVIEW

Allergen immunotherapy (AIT) has been shown to be safe and effective in children and is a unique treatment strategy that has disease-modifying and preventative effects that are not shared with other treatment options for allergic diseases. This article reviews the present knowledge and relevant updates on AIT in children.

RECENT FINDINGS

Although there is no definite lower age limit for starting AIT, clear indications for AIT are established and each case should be considered individually by weighing risks and benefits. Documented short- and long-term benefits of AIT in children with allergic disease include significant improvement of symptoms and quality of life, and decreased use of medications as well as preventing the development of new allergen sensitizations and the progression of allergic rhinitis to asthma. This review provides a comprehensive overview of the present knowledge and key updates on AIT in the pediatric population.

Subcutaneous Allergen Immunotherapy in Children: Real Life Compliance and Effect of COVID-19 Pandemic on Compliance

Background

Subcutaneous allergen immunotherapy (SCIT) is an effective treatment for allergic rhinitis, asthma, and venom allergy. Compliance is essential for SCIT to obtain maximal benefit as it is a long-term treatment.

Objectives

This study aimed to determine the level of real-life SCIT compliance in pediatric patients and the associated factors. Additional aims were to determine how SCIT compliance was affected by the COVID-19 pandemic and why some patients dropped out SCIT.

Method

Pediatric patients diagnosed with allergic rhinitis, allergic asthma, or venom allergy that received SCIT between September 2012 and July 2020 were analyzed.

Results

The study included 201 children (66.7% male) with a median (interquartile range) age of 12.8 years (9.4–15.2) at the time of the first SCIT injection. The overall compliance rate before COVID-19 pandemic was 86.1%. Short SCIT follow-up time and venom anaphylaxis were found to be risk factors for drop out. The leading causes of drop outs were moving to another city/country (32.1%), symptom improvement (17.8%), treatment ineffectiveness (14.2%), and adverse reactions (14.2%). Among the 108 patients that were still receiving SCIT during the COVID-19 pandemic, 31 (28.7%) dropped out the therapy. The most frequent reasons for drop-out were fear of being infected with COVID-19 (35.4%) and thinking that the AIT practise stopped due to COVID-19 pandemic (29%). Male gender and older age were found to be the independent risk factors for drop-out of SCIT.

Conclusions

Real life compliance in children was found 13.9% and it was higher than adults. Nearly one-third of children dropped out during the CO­VID-19 pandemic. Male gender and older age are associated with SCIT drop-out during the COVID-19 pandemic.

A twenty-two-year experience with Hymenoptera venom immunotherapy in a US pediatric tertiary care center 1996-2018

BACKGROUND

The rate of systemic reactions (SRs) to venom immunotherapy (VIT) in children has not been well evaluated.

OBJECTIVE

To evaluate the rate of SRs to VIT in pediatric patients age 5 to 18 years who were treated with a standard protocol.

METHODS

A retrospective chart review was conducted to identify patients who received VIT at Boston Children's Hospital from 1996 through 2018. Information on venom testing, severity of reaction to insect field sting, and SRs to VIT were retrieved.

RESULTS

A total of 78 patients were included. Most had moderate to severe reactions to insect sting before VIT. The rate of SRs was 0.2% of injection visits, occurring in 9% of patients. The SRs from VIT were mild (mostly grade 1 and some grade 2), and no grades 3, 4, or 5 reactions were seen. Male sex was a significant risk factor for moderate to severe reactions to insect sting. Positive testing to vespinae was seen in 98.7% of patients, and none had exclusive sensitivity to honeybee. The severity of the initial, pre-VIT insect sting reactions in our patients did not correlate with the occurrence of SRs from VIT. Twenty-seven percent of the patients were subsequently stung while on VIT. Only 1 patient (5%) had a mild SR, while all others had only local or no reaction at all.

CONCLUSION

In the largest US study evaluating the safety of VIT in children, SRs to VIT were mild, and none required epinephrine. Male sex was significantly associated with higher risk of moderate to severe reactions to insect sting. Larger multicenter studies are needed to further evaluate the rate of SRs to VIT in pediatric patients.