At a population prevalence of 3–5%, insect venom allergy is common and can potentially trigger life-threatening allergic reactions [1]. Therefore, patients who have experienced a systemic allergic reaction to an insect sting should be referred to an allergy specialist for diagnosis and treatment. In addition to patient history taking, where the symptoms and concomitant circumstances of the reaction are recorded, the standard procedure includes titrated skin prick testing and, if necessary, intracutaneous testing and/or determination of specific immunoglobulin (Ig)-E antibodies to insect venom and, where appropriate, their components to identify immediate-type allergy (Fig. 1). For a better risk assessment, especially after the onset of severe reactions, the determination of basal serum tryptase is also recommended. If the above-mentioned findings are positive and the patient has a clear history of a systemic allergic reaction in the context of a venom sting, the initiation of allergen-specific immunotherapy with the relevant insect venom is recommended [2].

Fig. 1
figure 1

Diagnostic algorithm for insect venom allergy (from [2]). IgE immunoglobulin E, sIgE specific immunoglobulin E

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The failure to initiate specific immunotherapy in at-risk patients in a timely manner, leads to an increase of their health risks and may result in an increased need of emergency care for insect sting reactions. Such situations should be avoided during possible healthcare shortage. The significance of the COVID-19 pandemic for allergology has recently been discussed in a number of position papers [3, 4]. Due to the widespread reduction in outpatient and inpatient care capacities in recent months as a result of the COVID-19 pandemic, the various allergy specialists from Germany, Austria, and Switzerland have taken different measures to ensure that patients with insect venom allergy continue to receive optimal allergy care. However, overall, there has been a large reduction in newly initiated insect venom immunotherapy (Table 1) during the lock down. A survey among large allergy centers with regard to newly initiated venom immunotherapy (VIT) revealed an almost 50% reduction for the months March–June 2020 compared to the similar period in 2019 (Fig. 2). This decline was related to reduced hospital capacities, but also the fact that patients considered to visit a physician or a hospital as a high-risk due to the COVID-19 pandemic.

Table 1 Overview of the number of VIT initiated in the period March–June 2019 and 2020 at a number of different centers
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Fig. 2
figure 2

Number of initiated VIT (total from 14 centers in Germany, Austria, and Switzerland) between March and June in 2019 compared to 2020. VIT venom immunotherapy

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Thus, the authors propose measures to ensure allergy care for insect venom-allergic individuals during times of emergency regulations in the healthcare system, such as during the COVID-19 pandemic (Table 2).

Table 2 Recommended measures for the care of insect venom allergy sufferers during the COVID-19 pandemic
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Continuation of already-initiated insect venom immunotherapy

Allergen-specific immunotherapy with insect venom that has already been initiated should be continued as consistently as possible, despite eventual limitations in medical resources, by making use of the permissible length of intervals (see also [3]). Interrupting specific immunotherapy can cause a loss of protection and leads to unnecessary expense at a later point as a result of having to re-start therapy if the treatment interval has been exceeded. If the patient has COVID-19 themselves, a pause in treatment is recommended until recovery. Following recovery, the dose should be re-up-titrated (if still within the permitted interval) or allergen-specific immunotherapy newly initiated if necessary. In some cases, it may be beneficial to contact the patient by telephone or telehealth appointment prior to their personal visit for the immunotherapy injection in order to rule out current contraindications to the injection, thereby potentially saving the patient an unnecessary visit.

New initiation of insect venom immunotherapy

It is possible to postpone the new initiation of insect venom immunotherapy out of season, assuming the time window is taken into account (see also [3]). Postponing initiation therapy during the summer season should be avoided, in order that the patient is not exposed to the risk of a repeat severe reaction to an accidental sting. Treatment initiation should preferably be performed as ultra-rush therapy under medical supervision. One- to five-day protocols have proven successful to this end [5, 6]. They have the advantage that the maximum dose is achieved after a short initiation treatment phase. Shortened outpatient up-titration protocols have also been investigated for vespid venom allergy patients and show good results in terms of safety [7]. However, they require a longer initiation phase (7 weeks), implying that such treatment protocols should be preferred out of the season.

In summary, the diagnostic work-up of insect venom allergy, including the patient history and skin testing, should be adapted to the prevailing conditions. Initiation of immunotherapy should continue to be started with ultra-rush protocols and, above all, not postponed during the summer season. During the out-of-season period and in case of shortages of inpatient resources, or in case of certain regional requirements, an up-titration can be performed in an outpatient setting. A shortened, 7‑week protocol for vespid venom allergy patients has been recently published [7]. Whenever possible, outpatient up-titration should be performed at a center experienced with this therapy and is able to provide emergency medical care.