AC Pica Pica (itchy Itchy) is really unusual this time of the year, it normally starts around April May time. Its the lava of the Thimble Jelly fish.
A vinegar solution is best to neutralize the stinging cells. Just apply to sensitive areas immediately after getting out of the water, then apply a good antihistamine cream to the area to stop the itching. Bring some Diprosone Cream with you or pick some up at a local pharmacy, it's the most effective relief for the itch from pica pica!!! Or use Eurox lotion on your skin and if it's a bigger problem, use Eurox and buy Atarax antihistimines. Avaiable over the counter.
It seems the reaction gets worse with each repeated exposure.