Seaweed Irritation Definition and Overview
Seaweed such as algae and coelenterates are found worldwide in salt water and fresh water and can cause skin irritation. Most algae and coelenterates cannot be seen by the naked eye, so exposures to them are usually accidental. Algae or coelenterates (for example, jellyfish) trapped underneath bathing suits usually cause a rash that results from irritation. Sometimes it is difficult to distinguish between seaweed and coelenterate-caused skin irritation. However, the seaweed rash usually occurs when swimmers have direct contact with Lyngbya majuscula seaweed when it gets under bathing suits or in areas where skin to skin contact occurs such as under the breasts or in the groin region. It is also common to see along the waistband of bathing suits. The seaweed occurs worldwide and resembles dark matted clumps of hair (gray, greenish-black, reddish and yellow colors) and produces two toxins that cause skin irritation.
Seaweed Irritation Symptoms
Itching, burning, redness are most common but in some people, blisters can develop. Swelling may occur in some individuals.
Scott D. Fell, DO, FAAEM