Diagnostic
sting challenges have been shown to provide information on the risk of further
anaphylactic reactions to bee
stings. We present a follow-up study in
wasp venom-hypersensitive children after diagnostic
venom extract challenges to analyze their risk of further
anaphylactic reactions. Responses were obtained from 104 patients with
wasp venom hypersensitivity out of 115 former patients. Only one of the 104 patients showed more than a severe local reaction to the
sting challenge irrespective of the performance of a single or sequential challenge; therefore, only one patient received venom immunotherapy. The performance of a diagnostic
sting challenge with
wasp venom extract in children had a high negative predictive value of 94.6% for the risk of further systemic reactions. This was shown by analysis of later field
stings, since 37 children experienced further field
stings and only two of these children(5.4%) developed a mild systemic reaction (
urticaria) equal to or less severe than the index
sting. The value of the
venom extract challenge can be interpreted in two ways: either it is less sensitive than a native
sting challenge since the rate of systemic reactions to the challenge was very low, or the prognosis of
wasp venom hypersensitivity in children is extremely favorable. Since the latter hypothesis is supported by the low incidence of systemic field
sting reactions, we postulate that venom immunotherapy is necessary only in a minority of children with
wasp venom hypersensitivity with an index
sting reaction of Mueller grade I or II. However, the value of
venom extract challenges as a general diagnostic instrument in children with Mueller I and II reactions due to
wasp venom hypersensitivity may be questioned. It may have a place as a safe procedure in demonstrating to parents and physicians the often self-limiting natural course in most of these children.