Auckland man itchy after spate of 'stinger' bites

The man developed an excrutiatingly itchy rash, while swimming at one of several Auckland beaches including Long Bay. Photo / File

An Auckland man is warning others of microscopic "stingers" at beaches after he was left with an uncomfortable itch.

The man, who doesn't want to be named, said he'd swam at several beaches around the city over the past few weeks, including Red Beach and Stanmore Bay, but most recently at Long Bay.

"It's excruciating. The itching combined with the muggy weather has left me writhing all night, unable to get comfortable. The warm water has meant I've been swimming a lot this summer but there really has been a sting in the tail."

It appeared the man was suffering from sea bather's eruption - an itchy or painful rash that affects areas covered by swimwear rather than areas left exposed. However it's not caused by jellyfish, but by an organism called siphonophore.

Children and those prone to allergic skin reactions are more likely to be severely affected, information on the Auckland Regional Public Health Service says.

"The worst part about is that the itchiness doesn't come until later," the man said, "So I think I've got away with it until I'm frantically scratching myself at work the following day.

"I've read that the little stingers can get caught in body hair but I don't much fancy a full body wax, I'm not that much of a swimmer."

Niwa confirmed the water temperature in the Hauraki Gulf is 21-23C - 1 or 2C above average for this time of year, perfect temperatures for the stingers, which are "very distant relatives of the jellyfish".

Niwa emeritus researcher and jellyfish expert Dennis Gordon said stingers are "string jelly", known among divers as "the long, stringy, stingy thingy".

"So think of a long string of 10 or more metres and along that string you've got really tiny spheres and they can break off in the water. They get trapped between your bathing suit and your skin so it's the movement of the togs against the skin that causes the stinging.

"Normally where jellyfish are concerned you would cover up your skin but with sea bather's itch you're better to go nude because there's no bathers to trap them between the skin and the togs."

The sting from the organism remained in swimwear so he advised, if stung, giving togs a thorough hot wash and drying them properly before wearing them again.