Portuguese man-of-war envenomation.

Portuguese man-of-war and jellyfish stings are common occurrence in the coastal waters of the southern United States. Signs and symptoms of Portuguese man-of-war envenomation usually appear immediately following a sting but may be delayed for several hours. Reactions are commonly localized and comprise pain, paresthesia, and intense burning with a linear, red, papular eruption or urticaria at the contact site. Systemic signs may include nausea, myalgia, headache, chills, or pallor. Cardiovascular collapse and death have been reported. Venom can be inactivated with dilute acetic acid (vinegar), proteolytic meat tenderizer, or baking soda. Tentacle debris should be removed. Resolution of symptoms usually occurs within 72 hours, without sequelae.