Please Note: This safety information is provided strictly as a courtesy in an effort to educate beachgoers and ocean enthusiasts on beach safety and not intended as medical advise. 808jellyfish is not a medical site. If a severe reaction occurs as the result of a box jellyfish sting immediately see a lifeguard for assistance, seek treatment at the nearest medical facility, or contact a physician.
 

For the average Hawaii Portuguese man-of-war sting:

 1. Pick off any visible tentacles with a gloved hand, stick, or anything handy, being
     careful to avoid further injury.

 2. Rinse the area liberally with seawater or fresh water to remove any tentacles stuck
     to the skin. This can be from a spray bottle or in a beach shower. Do not apply
     vinegar. A study shows that vinegar in these stings sometimes makes the sting
     worse.

 3. Apply ice for pain control.

 4. Irrigate exposed eyes with copious amounts of room temperature tap water for at
     least 15 minutes. If vision blurs, or the eyes continue to tear, hurt, swell, or are
     light sensitive after irrigating, see a doctor.

 5.  For persistent itching or skin rash, try 1 percent hydrocortisone ointment four
     times a day, and one or two 25 milligram diphenhydramine (Benadryl) tablets every
     6 hours. These drugs are sold without prescription. Diphenhydramine may cause
     drowsiness. Don't drive, swim or surf after taking any medications.

Although formerly considered effective, vinegar is no longer recommended for Portuguese man-of-war stings. In a laboratory experiment, vinegar dousing caused discharge of nematocysts from the larger (P. physalis) man-of-war species. The effect of vinegar on the nematocysts of the smaller species (which has less severe stings) is mixed: vinegar inhibited some, discharged others.

No studies support applying heat to Portuguese man-of-war stings. Studies on the effectiveness of meat tenderizer, baking soda, papain, or commercial sprays (containing aluminum sulfate and detergents) on nematocyst stings have been contradictory. It's possible these substances cause further damage. In one U.S. Portuguese man-of-war fatality, lifeguards sprayed papain solution immediately on the victim's sting. Within minutes, the woman was comatose, and later died.

Alcohol and human urine may be harmful on Portuguese man-of-war stings. An Australian study reports that both alcohol and urine caused massive nematocyst discharge in the box jellyfish, Chironex fleckeri.

Most Hawaii Portuguese man-of-war stings disappear by themselves, sometimes within 15 or 20 minutes. Because of this, even harmful therapies often appear to work. A key concept in the first aid of any injury is: Do no harm. Therefore, avoid applying unproven, possibly harmful substances on stings.

See a doctor if pain persists, the rash worsens, a feeling of overall illness develops, a red streak develops between swollen lymph nodes and the sting, or if either area becomes red, warm and tender.

Few Portuguese man-of-war stings in Hawaii cause life-threatening reactions, but this is always a possibility. Some people are extremely sensitive to the venom; a few have allergic reactions. Consider even the slightest breathing difficulty, or altered level of consciousness, a medical emergency. Call for help and use automatic epinephrine injector if available.

Excerpts from: ALL STINGS CONSIDERED Craig Thomas,M.D., and Susan Scott