Miami Beach Saturated with Portuguese Man O' War
Miami Beach, United States

One of many Man O' War found on Miami Beach

OK, that's scary… I did a little research on the odd-looking jellyfish that I found washed up on the beach (in great numbers) yesterday, and discovered that they're Portuguese Man O' War (which are actually siphonophores, not jellyfish).

I'm familiar with the name and dangerous reputation of the Man O' War, but really had no idea what one looked like. Frankly, I thought they were only found around the shores of Australia, but seem to have confused it with the hyper-toxic (read: deadly) box jellyfish.

I really hate jellyfish (and siphonophores, apparently), and the idea of these things floating around in the water here scares me. I'm freaked out a little by the sharks as it is, but tossing indigo balloons with deadly tentacles that can reach up to 165 feet (50 meters) long into the mix is a little much.

Wikipedia has this to say:

The sting from the tentacles is dangerous to humans. These stings usually cause excruciating pain, and have even been the cause of several deaths. Detached tentacles and specimens which wash up on shore can sting just as painfully as the intact creature in the water for weeks after their detachment. The venom can travel up to the lymph nodes and may cause, depending on the amount of venom, more intense pain.

With extensive or repeated exposures systemic reactions can take place, such as; nausea, vomiting, headaches, dizziness, muscle weakness, excessive tearing, runny nose, painful breathing, and irregular heart rate may occur. Medical attention is usually necessary, especially in extreme cases.

How to treat the average Portuguese Man O' War sting encountered on Miami Beach

1. Pick off any visible tentacles with a gloved hand, stick, or anything handy, being careful to avoid further injury.
2. Rinse the sting thoroughly with salt or fresh water to remove any adhering tentacles.
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 this medication.

Although formerly considered effective, vinegar is no longer recommended for Portuguese Man O' War stings. In a laboratory experiment, vinegar dousing caused discharge of nematocysts from the larger (P. physalis) Man O' 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 Man O' 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 O' 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 O' War stings. An Australian study reports that both alcohol and urine caused massive nematocyst discharge in the box jellyfish, Chironex fleckeri.

Most Portuguese Man O' 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.