Seabather’s eruption in Ipanema Beach, Rio de Janeiro, Brazil

In January 2017, a 28-year-old man presented with a 1-day history of burning and itching cutaneous lesions. He was concerned about the possibility of having acquired a communicable disease. The patient bathed and swam at Ipanema Beach (22°59′01″S; 43°12′16″W), Rio de Janeiro, the previous 4 consecutive days. On examination, around 30 erythematous papules and macules were distributed in a male swimwear pattern (Figure 1). No systemic symptoms were observed. A topical corticosteroid cream was prescribed, with complete remission of the lesions 1 week later.

FIGURE 1:
Clinical images of a 28-year-old man with a 1-day history of erythematous papules and macules distributed in a male swimwear pattern.

The rash was consistent with seabather’s eruption, a pruritic dermatitis occurring after contact with larvae of some marine animals, such as the thimble jellyfish Linuche unguiculata¹. The planula larvae of this cnidarian are small enough (approximately 0.5mm) to pass through the fabric weaves of most swimwear and become trapped against the skin. External pressure or osmotic changes, including contact with freshwater, triggers the discharge of toxins by organelles called nematocysts. The diagnosis is established based on history of exposure to seawater followed by the appearance of rash in the peculiar topography of the areas covered by the bathing suit¹.

Possible preventive measures include the use of sunscreen under the swimwear, tight-weave (instead of open-weave) fabric, a female two-piece instead of one-piece swimsuit, and avoidance of T-shirts and showering with fresh water while wearing a contaminated suit. In Brazil, this marine envenomation is mainly reported in the coastal areas of São Paulo² and Santa Catarina³ states. We are unaware of previous reports from the State of Rio de Janeiro.

REFERENCES

• ¹
  MacSween RM, Williams HC. Seabather's eruption--a case of Caribbean itch. BMJ. 1996;312(7036):957-8.
• ²
  Haddad Jr V, Cardoso JL, Silveira FL. Seabather's eruption: report of five cases in southeast region of Brazil. Rev Inst Med Trop Sao Paulo. 2001;43(3):171-2.
• ³
  Rossetto AL, Dellatorre G, Silveira FL, Haddad Jr V. Seabather's eruption: a clinical and epidemiological study of 38 cases in Santa Catarina State, Brazil. Rev Inst Med Trop Sao Paulo . 2009;51(3):169-75.

• Informed consent: Informed consent of the patient was obtained for publication of the case.

Publication Dates

• Publication in this collection
  Jan-Feb 2018

History

• Received
  06 Feb 2017
• Accepted
  24 Apr 2017