Swimming Alert: Microscopic jellyfish
5 February 2008
Microscopic jellyfish may be causing the rash often blamed on sea lice
Auckland Regional Public Health Service (ARPHS) warns the public to take care swimming at Takapuna Beach where some swimmers are reporting rashes caused by stings from microscopic jellyfish. Swimmers should also take care on other East Coast beaches as warm weather and on-shore breezes bring the microscopic jellyfish towards the beaches.
These jellyfish, which are too small to be seen, get caught inside togs and tend to sting skin areas covered by togs once the swimmer gets out of the water. The rash can become red, itchy and painful.
Dr Simon Baker, Medical Officer of Health, Auckland Regional Public Health Service says, “The only sure-fire way of avoiding this rash is not to swim at affected beaches. So far, most cases have been from Takapuna beach, but we have heard of people with rashes after swimming at other beaches – such as Kohimarama and St. Helier’s.”
- The only certain way to prevent being stung is to avoid swimming at affected beaches or to swim in a freshwater swimming pool instead.
- Do not wear large baggy clothes into the water (but still stay sun smart).
- After swimming, remove your togs as soon as possible and then shower if you can – especially the area that was covered by your togs. If there is a saltwater shower, it is best to use that. If not, a freshwater shower is better than nothing.
- If you develop a rash, have a shower, and get into cool clothing. Calamine lotion may help.
- If the rash persists, visit your local pharmacy – mild steroid creams like hydrocortisone can be helpful, as can antihistamine tablets.
- If problems are severe or persist or worsen, see a doctor.
- Don’t put the togs back on till laundered properly, as the jellyfish can still sting even after they are dead.
Little is known about the habits of these tiny jellyfish and until recently the rash was thought to be caused by sea lice; however sea lice tend to bite on exposed areas of skin, whereas the jellyfish normally sting beneath togs.
“We know this is the time of year that people want to be at the beach. We just want people to have the information they need to make choices for their own and their families’ good health,” says Dr Baker.