Vinegar (3–10% aqueous acetic acid) may help with box jellyfish stings but not the stings of the Portuguese man o' war. Clearing the area of jelly and tentacles reduces nematocyst firing. Scraping the affected skin, such as with the edge of a credit card, may remove remaining nematocysts. Once the skin has been cleaned of nematocysts, hydrocortisone cream applied locally reduces pain and inflammation. Antihistamines may help to control itching. Immunobased antivenins are used for serious box jellyfish stings.
Vinegar (3–10% aqueous acetic acid) may help with box jellyfish stings but not the stings of the Portuguese man o' war. Clearing the area of jelly and tentacles reduces nematocyst firing. Scraping the affected skin, such as with the edge of a credit card, may remove remaining nematocysts. Once the skin has been cleaned of nematocysts, hydrocortisone cream applied locally reduces pain and inflammation. Antihistamines may help to control itching. Immunobased antivenins are used for serious box jellyfish stings.