A study of jellyfish stings in Hawaii and on the mainland has found no one treatment vastly superior to others, but putting hot water and a mild painkiller on the sting appears "more widely beneficial," the researchers say.

Applying vinegar to the sting seems to increase the pain, except with the Portuguese man-o-war, said the research team, made up of four doctors at the UC San Diego Medical Center.

Their review of the relevant medical literature was published June 8 in the Annals of Emergency Medicine under the title, "Evidence-Based Treatment of Jellyfish Stings in North America and Hawaii."

"Hot water and topical lidocaine appear more widely beneficial in improving pain symptoms and are preferentially recommended," their report says.

Unfortunately, they say, those items may be difficult to get at beaches or dive sites.

So removing the barbs and washing the area with salt water is perhaps the best approach, they say.

Among the proposed treatments they looked at were vinegar, urine, ammonia, hot water, ice, a cold pack, baking soda, meat tenderizer and local anesthetics such as lidocaine or benzocaine. Aloe was not mentioned.

In Hawaii, box jellyfish typically appear near shore a week to 10 days after the full moon, with most stings occurring at the crowded Waikiki and Ala Moana beaches. They are due next between July 10 and July 14.

Their venomous stings, delivered by a barbed capsule called a nematocyst, can be very painful and can even cause anaphylactic shock in some individuals.

The authors pointed to two 2001 reports in the Hawaii Medical Journal.

One studied the effects of hot and cold packs on stings on 133 swimmers here. The hot packs won out, significantly reducing pain within 10 minutes. Cold packs didn’t reduce the pain.

The second study compared the application of seawater, fresh water, Adolph’s meat tenderizer and an antiseptic spray called Sting-Aid (aluminum sulfate). The subjects were 62 swimmers who had been stung by box jellyfish in Hawaii.

Nothing worked better than sea water.

The authors looked at all English-language studies relating to true jellyfish, box jellyfish (Carybdea alata) and Portuguese man-o-wars (genus Physalia) and found 19 pertinent articles.

Hot water or a hot shower seems to work better than vinegar or Adolph’s meat tenderizer, according to a study using 25 volunteers who were stung on both arms.

Hot water also seems to work best on Portuguese man-o-war stings, they found.

A 2002 report on 113 patients who were stung by jellyfish on west Oahu between 1994 and 1998 found that hot water relieved pain in 23 of 25 cases, much better than painkillers or tranquilizers.

Nothing works perfectly, they said.

"Current recommended treatments of cnidarian stings involve two distinct yet ideally simultaneous strategies," the authors say. "One is to reverse the pain and tissue damage from the venom itself. The second is to prevent further discharge of venom-laden nematocysts to allow their eventual removal intact. Some therapies might be successful at the former but fail or worsen effects with regard to the latter. Different effects across different classes or species of jellyfish may occur. The perfect agent would be readily available, cheap, capable of inactivating venom, and applicable across multiple species of jellyfish and would block further release."

The American Heart Association and the American Red Cross recommend applying vinegar or baking soda, followed by a heat pack — or an ice pack if heat is not available, the doctors note.

But the doctors take issue with vinegar.

"Our review, however, suggests that vinegar may not be an ideal agent because it causes pain exacerbation or nematocyst discharge in most species except Physalia," they said.