By Gary M. White, MD

Jellyfish sting Courtesy O. Dale Collins, MD

Jellyfish and Portuguese Men-Of-War are gelatinous animals of the Phylum Cnidarians. Contact with their tentacles causes immediate pain from toxic action. Linear skin lesions develop from both toxic and allergic mechanisms.


Intense and immediate pain occurs in areas that come into contact with the animal and may last for hours. Within minutes of contact, linear urticarial, red lesions develop. Within a matter of hours, the area may develop vesicles, blisters and even superficial necrosis.

In severe cases, localized hyperhidrosis, lymphadenopathy, limb necrosis, and gangrene may occur. Rare but potential systemic complications in severe cases include hemolysis and renal abnormalities, shock, respiratory failure and heart failure.


Various authors recommend trying to inactivate stinging cells on the surface with vinegar or alcohol (or at least wash with salt water). Antihistamines can reduce "wheal and flare" reaction. Topical steroids may speed healing time. In order to prevent, wear a rash guard!

Additional Pictures

Sting by Portuguese Man of War. This young man was snorkeling off the coast of Maui when he felt an immediate burning and stinging on his right arm. He quickly swam to shore. This photo was taken soon thereafter.
Skin lesions from Portuguese man-of-war Sting


JAAD November 2009;Volume 61, Issue 5, Pages 733–750


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