ACMT Visual Pearl: Seabather’s Eruption: The unexpected beach burn

1. Jellyfish

What is seabather’s eruption?

Seabather’s eruption is a pruritic dermatitis caused by contact with the planula or larval form of sea anemones and jellyfish [1]. It has also been called Pica-Pica (Spanish for itchy-itchy) or ‘sea lice’ [1,2]. Characterized as small, itchy welts, it is contracted in coastal waters of both the Atlantic and Pacific oceans [1]. The rash tends to be more severe in areas of the skin covered by clothing in the water, but it may also occur on exposed skin [1,3]. Bathing suits trap the larvae against the skin, resulting in multiple stings. Rashes can occur immediately after exposure to the water and up to 2 days after swimming [2].

What causes seabather’s eruption?

• Exposure to microscopic forms of jellyfish, coral, and sea anemones (belonging to the phylum Cnidaria) causes the rash of sea bather’s eruption [1, 3-5].
• The incidence occurs from March through August, with the peak of the larval population being found in May [2,4,5].
• The small organisms often become trapped in between the skin and bathing attire. When the organism’s nematocysts are triggered by osmotic changes (bathing in freshwater) or with friction (rubbing with a towel or exiting the ocean), they sting the skin, releasing venom [1]. The venom is a mixture of toxic and antigenic enzymes and peptides [6].

How does seabather’s eruption present?

• Patients may initially feel a tingling or stinging sensation, then a pruritic, erythematous maculopapular rash develops [3,7]. It is thought that the initial stinging feeling is from the direct effect of the venom and that the subsequent rash is immune-mediated [1,4].
• The duration of the rash ranges from 3 days to several weeks [1,3,7].
• Severe symptoms are uncommon and may include malaise, fever, abdominal pain, nausea, and headache [1-4].
• The differential diagnosis of seabather’s eruption includes scabies, ringworm, cutaneous larva migrans, seaweed dermatitis, and cercarial dermatitis [1,8].

How do you treat seabather’s eruption?

• The most efficient way to avoid seabather’s eruption is abstaining from seawater activities when the responsible organisms are present (warmer months). Treatment may be more feasible than prevention [1,6].
• Barrier creams have not been shown to be effective [1,2].
• After leaving the water, immediately rinse off in unaffected seawater to avoid triggering the remaining larvae. Fresh water may trigger nematocysts to discharge, so showering with the bathing suit off is advisable [1,2]. Nematocysts may retain the ability to sting if they remain on the bathing suit even after the suit is dry and for up to two weeks, so suits should be thoroughly washed after use [1,3,4].
• Avoid friction, such as toweling off or applying pressure to the area, as this may trigger the release of more nematocysts [1,3].
• If stinging continues after removing the wet clothing and rinsing in fresh seawater, diluted vinegar or 5% acetic acid can be used to rinse the skin to neutralize residual toxins [1,4,5].
• Antihistamines or topical steroids can minimize symptoms of tingling and sensitivity [1,3-5,7]. Non-steroidal medications can help with pain [8]. Oral steroids can be used in severe cases [1,9].

Bedside Pearls

• Sea bather’s eruption is a pruritic dermatitis caused by contact with the planula or larval form of sea anemones and jellyfish [3].
• It may initially feel like a tingling or stinging sensation, then a pruritic, erythematous maculopapular rash develops [3,7].
• Severe symptoms may include malaise, fever, abdominal pain, nausea, dyspnea, and headache, but are much less common [1-4].
• Antihistamines or topical steroids can minimize symptoms of tingling and sensitivity [1,3-5,7]. Non-steroidal medications can help with pain [8]. Oral steroids can be used in severe cases [1,9].