Prophylactic treatment of jellyfish stings--a randomised trial

Contact with jellyfish can cause skin irritation and manifestations. We wanted to investigate the prophylactic effect of a sun cream containing an inhibitor against jellyfish stings.

We recruited 38 persons who were randomised such that each received two of three possible treatments, one on each underarm. Prophylactic treatment with sun cream containing jellyfish sting inhibitor, ordinary sun cream, and no cream. Their underarms were exposed to wet jellyfish tentacles in a watchglass. The following were recorded: time before pain, skin changes after four minutes, and pain intensity after 10 minutes, registered on a VAS scale.

Thirteen of 25 subjects who had the sun cream with jellyfish sting inhibitor did not register any pain after 4 minutes' exposure, compared with two of 25 and two of 26 who had received pre-treatment with ordinary sun cream (p = 0.32) and no pre-treatment (p < 0.001), respectively. On average, subjects who had received prophylactic treatment with sun cream containing jellyfish sting inhibitor recorded a lower VAS score for pain/discomfort after 10 minutes. The difference was 10.6 mm (95 % CI 3.1-17.9) compared with ordinary sun cream and 14.2 mm (95 % CI 6.9-21.5) compared with no pre-treatment. A smaller number of subjects were found to have underarms with inflamed skin when prophylactic cream containing jellyfish sting inhibitor was used (6 of 25) than when ordinary sun cream was used (11 of 25) or no pre-treatment (12 of 26). There were no statistically significant differences between ordinary sun cream and no pre-treatment for any of the three outcomes.

Prophylactic treatment with jellyfish sting inhibitor reduces the risk of subjects developing symptoms after exposure to jellyfish tentacles.