D3.198 - Hymenoptera Venom Allergy: A Case Report on Safe Discontinuation After Five Years of Venom Immunotherapy
Case report
Background: Hymenoptera venom allergy is a potentially life‐threatening condition. Venom immunotherapy (VIT) is the treatment of choice for patients experiencing systemic reactions. Accurate diagnosis through clinical history and in vivo and in vitro tests is essential to identify the primary Hymenoptera venom sensitiser and appropriate VIT choice. The optimal duration of therapy and criteria for discontinuation remain debated. This case highlights a successful VIT discontinuation.
Case Presentation: We report a case of a 60-year-old woman with a history of two vespid sting reactions, the second one with hypotension and generalized urticaria. Skin testing and serum-specific IgE levels revealed predominant sensitisation to Polistes dominula venom, with low reactivity to other vespid venoms. VIT for Polistes dominula venom was initiated. During VIT, the patient experienced two more vespid stings, both causing mild local reactions. After five years of VIT, repeated serological evaluations and skin tests were negative, supporting the decision to cease VIT.
Discussion: This case highlights key aspects of VIT management and discontinuation and the decision to discontinue VIT should be individualised. For patients without specific risk factors, a minimum VIT duration of 5 years is recommended, whereas for high-risk patients, such as those with severe reactions, mast cell disorders or occupational exposure, VIT should be continued beyond 5 years, to maintain protection. Testing is not strictly required when considering VIT discontinuation. Negativisation of skin tests and specific IgE levels is rare, but patients remain protected even in the absence of negativisation. Another method to assess VIT efficacy is the sting challenge but it is not commonly performed in Italy due to ethical and logistical issues. Long-term follow-up is crucial, especially after re-stings.
Conclusions: The long-term efficacy of VIT is demonstrated by the absence of systemic reactions during therapy. However, discontinuing VIT is particularly challenging in patients not re-stung due to effective environmental prophylaxis. While complete negativisation of allergy tests would ideally support discontinuation, this is rare. Therefore, decisions to cease VIT should be tailored to the individual, considering clinical findings and risk factors, in line with current guidelines. A multi-modal diagnostic approach, including clinical, serological, and skin tests, is crucial for managing VIT.
