Prediction, prevention, and mechanism of early (anaphylactic) antivenom reactions in victims of snake bites.

Abstract

Victims of snake bites are often subjected to cutaneous or conjunctival hypersensitivity testing before being given antivenom. None of 12 early (anaphylactic) reactions was predicted by these tests in 25 Nigerian and Thai patients. The incidence and severity of early reactions was the same whether antivenom was given by intravenous injection over 10 minutes or diluted and given as an intravenous infusion over 30 minutes. Although antivenom activated complement in vitro, there was no evidence of complement activation or formation of immune complexes in patients bitten by snakes who were treated with antivenom, whether or not they developed early reactions. Higher doses of antivenom might induce the complement activation and formation of immune complexes (aggregates) that have been observed during the clinically more severe reactions associated with homologous immunoglobulin treatment.

A Controlled Clinical Trial of A Novel Antivenom in Patients Envenomed by Bungarus multicinctus

“…With the aim of protecting its stability, the antivenom was not diluted in large amounts of solution in our study, but nevertheless was infused slowly during a period of 1 h. Since skin testing is today not only considered unnecessary but also misleading, and pretreatment with antihistamine, epinephrine, or corticosteroids is controversial, neither a skin test nor any pretreatment was performed in the present study [14][15][16][17].…”

A study of outcome of neuroparalytic snake bite patients treated with fixed dose of antisnake venom

“…4 This test may reveal IgE mediated type 1 hyper sensitive reaction to horse protein but do not predict the large majority of early anaphylactic or late serum sickness type anti venom reactions as they are mediated by direct activation of complement system and not mediated by IgE. 15,16 Skin testing only delay the administration of ASV and can in themselves cause sensitization.…”

Dealing with adverse reactions to snake antivenom

“…Skin testing has been used historically to predict such reactions. However, this method is poorly predictive of early adverse reactions to antivenom [4,5].…”