- D1.517 - Adverse Reactions to Insect Venom Immunotherapy in a Reference Center

Hymenoptera venom extracts are used in immunotherapy for allergic individuals with the aim of reducing sensitivity and preventing severe allergic reactions. To date, there are limited data in the literature regarding immunotherapy protocols, particularly for fire ant venom, with small sample sizes, variable reaction rates, and treatment efficacy, reflecting the wide variation in insect species across different geographic regions worldwide.

To describe the characteristics and outcomes of hymenoptera venom–specific immunotherapy in a reference center.

Seven patients were evaluated; 57% were male, with a mean age of 33.28 years (range: 6–68 years). All patients had experienced severe anaphylactic reactions classified as Müller grade III. All lived in urban areas. Four patients were treated with fire ant venom, two with wasp/hornet venom, and one with honeybee venom. The mean serum levels were: IgE 449.8 kU/L, IgA 79.7 mg/dL, IgM 99.34 mg/dL, IgG 964.75 mg/dL, tryptase 5.29 ng/mL, and IgG4 40.42. All patients were treated using a cluster protocol.Three patients treated with fire ant venom developed significant local reactions during both the induction and maintenance phases. Another fire ant–allergic patient developed urticaria during the induction phase, and one patient developed urticaria during the maintenance phase (fourth month) with Polistes venom. In these cases, prophylactic antihistamines and corticosteroids were initiated, along with local cold compresses, resulting in improvement of systemic symptoms, although local reactions persisted.Most reactions were local, and two systemic reactions occurred; however, these were mild and occurred during both the induction and maintenance phases.

Insect venom immunotherapy using a cluster protocol is safe; however, patients require continuous monitoring in a specialized setting, as reactions may occur at any stage of treatment. Studies evaluating the efficacy of cluster, rush, and ultra-rush protocols are still limited, particularly in Brazil.