4-54
Follow-up Actions
Evacuation/Consultation Criteria: Evacuation not necessary. Consult dermatology or infectious disease
as needed.
Skin: Swimming Dermatitis
(Sea Bather's Eruption [salt water], Swimmer’s Itch [fresh and salt water])
MAJ Daniel Schissel, MC, USAIntroduction: Swimming dermatitis occurs globally and takes two forms. Sea bather’s eruption is caused by
contact with larvae of a marine jellyfish that release a toxin when trapped between clothing and the skin. It
typically presents in areas covered by clothing or swim wear, unlike swimmer’s itch, which usually occurs
in exposed areas. Cercarial dermatitis is more commonly known as swimmer’s itch in the fresh waters of
the north central United States, and clam digger’s itch along the coastal salt waters. It is caused by the
penetration by immature forms (cercariae) of a schistosome that normally infest birds, into the skin of an
unsuspecting swimmer or bather. The cercariae die later in the skin, self-limiting the infection.
Subjective: Symptoms
Prickly eruption (rash, itching) within a few minutes to hours where the larvae sting or the cercaria penetrate;
repeated exposure (allergic response) cause larger, longer lasting, and more pruritic lesions in cercarial
dermatitis.
Objective: Signs
Using Basic Tools: Fine, papular rash in covered areas (sea bather’s eruption) or exposed areas (swimmer’s
itch); lasts hours (swimmer’s itch) to days; scratches often become secondarily infected; repeated cercaria
exposures cause larger, longer lasting papules, that may advance to pustules and vesicles over a 3 to 4
days.
Assessment:
Diagnosis based on clinical presentation and history of exposure in infested waters.
Differential Diagnosis
Swimmer’s itch, allergic or irritant contact dermatitis
Plan:
Treatment
Primary: These are self-limited diseases. Treatment consists of symptomatic relief of pruritus with
antihistamines and prevention of secondary infection in areas of excoriation. Topical steroids can alleviate
more advanced allergic reactions to repeated exposures to cercaria.
Patient Education
General: Prevent cercarial dermatitis by avoiding prolonged immersion in infested waters and treating
infested fresh water streams and lakes with a mixture of copper sulfate and carbonate, or sodium
pentochlorphenate. Dry briskly after potential exposure to remove cercaria before they have sufficient time to
penetrate. Apply 20% copper sulfate solution to the skin and allow to dry prior to potential exposure.
Follow-up Actions
Evacuation/Consultant Criteria: Do not evacuate patients. Generally no need to consult specialists.