AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

Seabather's eruption was first described in 1949 as a pruritic papular eruption occurring in bathers off the eastern coast of Florida. Seabather's eruption is a highly pruritic, papular eruption that occurs underneath the swimsuit after extended exposure to seawater. Seabather's eruption results from a hypersensitivity to the larval form of the thimble jellyfish, Linuche unguiculata.¹ Most cases occur from March to August, but the incidence peaks in May and June.

A related eMedicine article is Cutaneous Manifestations Following Exposures to Marine Life. Additionally, the Medscape CME course Climate Change and Public Health may be of interest.

Pathophysiology

Seabather's eruption is a cutaneous hypersensitivity reaction to the larval form (planulae) of the thimble jellyfish, L unguiculata. The eruption typically occurs underneath the bathing garments, which are believed to trap the jellyfish larvae against the skin. Whether the discharge of venom by the trapped larvae plays an important role in the pathogenesis of the eruption remains uncertain. Factors that promote the discharge of venom by the larvae include wearing of bathing suits for prolonged periods following swimming, exposure to fresh water through showering, and mechanical stimulation.

Frequency

United States

The incidence of seabather's eruption is seasonal; the highest incidence occurs from May through August. This coincides with the warm gulf streams running along the Atlantic coastline of Florida and the corresponding spawn of thimble jellyfish larvae, which results in the high seasonal concentration of Linuche planulae. In 1997, Kumar et al² reported the occurrence of seabather's eruption in Palm Beach saltwater swimmers in May to be 16%.

International

Seabather's eruption has been reported in Mexico and the Caribbean. The true prevalence of seabather's eruption along international coastlines remains unknown.

Mortality/Morbidity

No deaths have been attributed to exposure to thimble jellyfish larvae.

Race

Seabather's eruption occurs independent of race.

Sex

Seabather's eruption has been noted with equal frequency in both sexes.

Age

No correlation between age and risk for developing seabather's eruption has been noted. The severity of symptoms, particularly the frequency of fever, is greater in children than in adults.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

The eruption begins a few hours after bathing in the ocean.

• Pruritus is the most common symptom in patients with seabather's eruption (98%). It typically lasts 1-2 weeks.
• Fever and malaise are the next most commonly observed symptoms (23%). Fever is observed in 18% of patients. However, 40% of patients younger than 16 years report fever compared with 10% of adults.
• Systemic symptoms, including fever, nausea, abdominal pain, and diarrhea, are more common in children than in adults.

Physical

On physical examination, patients with seabather's eruption typically display inflammatory papules in a distribution pattern that mimics the bathing suit. Lesions have been noted to occur in the axillae; in men with significant chest hair, they occur on the chest.

• Relatively rare signs and symptoms of seabather's eruption include the following:
• • Nausea
  • Headache
  • Sore throat
  • Cough
  • Diarrhea
  • Abdominal pain

Causes

Seabather's eruption is caused by exposure to the larval form (planulae) of the thimble jellyfish, L unguiculata.

• The seasonal variation in the concentrations of thimble jellyfish larvae in endemic areas lead to the increased incidence of seabather's eruption from May through August, with a peak in May and June.
• Freudenthal and Joseph³ reported the larvae of the sea anemone Edwardsiella lineata as the cause of an outbreak of seabather's eruption on Long Island, New York. This organism also has nematocysts. Various species of Cnidaria larvae in other waters can likely produce similar eruptions.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

Swimmer's itch

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Lab Studies

• Diagnosis of seabather's eruption is made based on the history of exposure and the physical examination. Laboratory studies and skin biopsy are unnecessary.
• Although only available for research purposes, Wong et al have demonstrated elevated serum levels of immunoglobulin G antibodies specific for L unguiculata.

Procedures

• A punch biopsy of involved skin may prove useful in narrowing the differential diagnosis when obtaining a reliable history of exposure is difficult.

Histologic Findings

A skin biopsy demonstrates a predominant superficial and deep perivascular and interstitial infiltrate consisting of lymphocytes, eosinophils, and neutrophils. Generally, no epidermal changes are noted, and the dermal-epidermal junction is intact.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical Care

Patients with seabather's eruption require only symptomatic or supportive therapy. Children more commonly demonstrate systemic symptoms, including fever, nausea, abdominal pain, and diarrhea. These symptoms may be mistaken for viral gastritis, possibly leading the patient to seek treatment in the emergency department.

• Use of topical corticosteroids in combination with antihistamines has yielded variable results. Systemic corticosteroids are generally reserved for patients demonstrating severe symptoms.
• Many anecdotes regarding the effectiveness of alternative remedies made with vinegar, rubbing alcohol, sodium bicarbonate, sugar, urine, olive oil, and meat tenderizer have been reported.

Consultations

A dermatologist can help narrow the differential diagnosis in difficult cases and facilitate a skin biopsy with histologic study.

Activity

Limitations on patients with seabather's eruption are unnecessary unless associated systemic symptoms are severe. However, Kumar et al² have shown that the risk of developing seabather's eruption in patients exposed to high seasonal concentrations of larvae while swimming in saltwater is significantly reduced if bathers shower with the bathing suit off, regardless of the length of time in the water or the timing of showers.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

High-potency topical steroids in combination with oral antihistamines are typically used in treating the cutaneous manifestations of seabather's eruption. Systemic corticosteroids should be reserved for patients with severe rash or pronounced associated systemic symptoms.

Drug Category: Corticosteroids

These agents have anti-inflammatory properties and cause profound and varied metabolic effects. In addition, these agents modify the body's immune response to diverse stimuli. They are effective in quickly reducing inflammation and pruritus.

Drug Category: Antihistamines

These agents prevent histamine response in sensory nerve endings and blood vessels. They are more effective in preventing histamine response than in reversing it. They also reduce pruritus.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Inpatient Care

• Patients rarely demonstrate associated systemic symptomatology severe enough to require hospitalization. Even then, treatment is largely supportive and should include systemic corticosteroids.

In/Out Patient Meds

• Topical corticosteroids in combination with oral antihistamines are used to relieve local symptoms.
• Systemic corticosteroids should be reserved for patients with a severe cutaneous eruption and pronounced systemic symptoms.

Deterrence/Prevention

• Showering with the bathing suit off is the only significant protective measure against seabather's eruption. Length of shower time; timing of the shower; bathing suit style; shower water temperature; towel drying upon emerging from the seawater; and application of ointment, creams, or lotions have no preventative effect.

Complications

• Because of the nature of the allergic hypersensitivity underlying the disease, patients are susceptible to recurrence upon reexposure. Reports have described exaggerated symptomatology in recurrent cases of seabather's eruption, and, for such individuals, avoiding seawater on affected beaches during seasonal peaks is best.

Prognosis

• Cutaneous eruptions clear in 2 weeks, with or without therapy.

Patient Education

• Educate patients about thimble jellyfish larvae during peak seasons in affected areas and the preventative role of showering with the bathing suit off following exposure to the seawater.
• For excellent patient education materials, visit eMedicine's Environmental Exposures and Injuries Center; Bites and Stings Center; and Jellyfish, Stingray, and Other Water Animal Bites/Stings Center. Also see eMedicine's articles Jellyfish Stings and Stingray Injury.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• Failure to make the diagnosis is a pitfall.
• • Thoroughly evaluate children who present with systemic symptoms of fever, malaise, fatigue, and rash to eliminate the diagnosis of bacterial meningitis. The distribution of the rash (that of a bathing suit), along with a history of saltwater exposure during spring and summer months along the eastern coast of Florida, should help to establish the diagnosis.
  • Consultation with a dermatologist proves helpful if an element of doubt exists in the diagnosis.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

1. Segura Puertas L, Burnett JW, Heimer de la Cotera E. The medusa stage of the coronate scyphomedusa Linuche unguiculata ('thimble jellyfish') can cause seabather's eruption. Dermatology. 1999;198(2):171-2. [Medline].
2. Kumar S, Hlady WG, Malecki JM. Risk factors for seabather's eruption: a prospective cohort study. Public Health Rep. Jan-Feb 1997;112(1):59-62. [Medline].
3. Freudenthal AR, Joseph PR. Seabather's eruption. N Engl J Med. Aug 19 1993;329(8):542-4. [Medline].
4. Bernhardt MJ, Mandojana RM. "Seabather's eruption". Clin Dermatol. Jul-Sep 1987;5(3):101-2. [Medline].
5. Burnett JW, Calton GJ, Burnett HW. Jellyfish envenomation syndromes. J Am Acad Dermatol. Jan 1986;14(1):100-6. [Medline].
6. Fisher AA. Toxic and allergic cutaneous reactions to jellyfish with special reference to delayed reactions. Cutis. Oct 1987;40(4):303-5. [Medline].
7. Kettle M. Americans adrift in an ocean of fears. The Guardian Weekly. February 8, 2001:Available at http://www.vuw.ac.nz/~caplabtb/dprk/adrift.html.
8. Letot B, Kharfi M, Mandojana R, Piérard GE. [Undesirable reactions from contact with marine organisms]. Rev Med Liege. Jun 2000;55(6):531-7. [Medline].
9. Mandojana RM, Letot B. Historical outlook of aquatic biotoxicology and balneology as related to dermatology. Classification of aquatic dermatoses. Clin Dermatol. Jul-Sep 1987;5(3):1-7. [Medline].
10. Mandojana RM, Sims JK. Miscellaneous dermatoses associated with the aquatic environment. Clin Dermatol. Jul-Sep 1987;5(3):134-45. [Medline].
11. Wong DE, Meinking TL, Rosen LB, Taplin D, Hogan DJ, Burnett JW. Seabather's eruption. Clinical, histologic, and immunologic features. J Am Acad Dermatol. Mar 1994;30(3):399-406. [Medline].

Article Last Updated: May 22, 2008