Efficacy of a jellyfish sting inhibitor in preventing jellyfish stings in normal volunteers.

OBJECTIVE To evaluate the protective effects of a jellyfish sting inhibitor formulated in sunscreen lotion vs conventional sunscreen against Chrysaora fuscescens and Chiropsalmus quadrumanus jellyfish. METHODS Twenty-four healthy subjects at 2 research sites were randomly assigned to receive the jellyfish sting inhibitor (Nidaria Technology Ltd, Jordan Valley, Israel) to one forearm and conventional sunscreen to the other arm in a blinded fashion. Subjects were stung with jellyfish tentacles on each forearm for up to 60 seconds. Erythema and pain were assessed at 15-minute intervals over a 2-hour period. RESULTS In the C. fuscescens group, all 12 arms pretreated with conventional sunscreen demonstrated erythema, and all subjects noted subjective discomfort. In contrast, no arm pretreated with the jellyfish sting inhibitor had objective skin changes (P < .01). Two subjects noted minimal discomfort in the arm treated with the sting inhibitor (P < .01). In the C. quadrumanus group, discomfort was reported in 3 of the 12 inhibitor-treated arms compared with 10 of the 12 placebo-treated arms (P < .05). Erythema was noted on 1 arm treated with the inhibitor and 9 arms treated with the placebo (P < .01). CONCLUSIONS The jellyfish sting inhibitor prevented sting symptoms of C. fuscescens jellyfish in 10 of 12 subjects and diminished the pain of the jellyfish sting in the remaining 2 subjects. The jellyfish sting inhibitor also inhibited the more severe sting of the C. quadrumanus jellyfish in the majority of subjects. The jellyfish sting inhibitor does not eliminate the sting from C. fuscescens or C. quadrumanus jellyfish but significantly reduces the frequency and severity of stings.