Seabather’s eruption: report of fourteen cases

Seabather’s eruption is a papulo-pruritic dermatitis caused by the nematocysts of the larvae of the jellyfish Linuche unguiculata retained in the clothing fibers. Previously reported in Brazil, this work describes fourteen cases that occurred in the State of Santa Catarina, in southern Brazil. The new cases observed over a short period of time (the first half of January, 2012), at the height of the summer season, should alert health teams to possible epidemics on the coast of the state


INTRODUCTION
Seabather's eruption (SBE) is a dermatitis clinically characterized by intensely pruritic erythematous papules located mainly in areas of the body covered by a bathing suit during, or shortly after, exposure to seawater (Haddad Jr 2008, Rossetto et al. 2009).
The diagnosis of the disease is based on clinical and epidemiological factor, and it responds well to treatment with a combination of systemic antihistamines and topical corticosteroids. The prognosis is good, and the dermatitis may evolve into spontaneous resolution in one or two weeks (Haddad Jr 2008, Rossetto et al. 2009). SBE is caused by entrapment of planula larvae of the jellyfish Linuche unguiculata under bathers' clothes, which in contact with the victim's skin, triggers the nematocysts (or cnidocytes) using its stinging cells for defense, causing dermatitis (Haddad Jr 2008, Rossetto et al. 2009). The planula larvae are about 0.5 mm in size, and become trapped by the fibers of the bathing suit, especially when the swimmer leaves the sea and the bathing suit drains the water, acting like a filter (Rossetto et al. 2007(Rossetto et al. , 2009. The process can also be triggered by contact with freshwater, or pressure (Haddad Jr 2008, Rossetto et al. 2009 L. unguiculata (Efira, planula larvae, and adult jellyfish), and that it differs clinically according to the morphology of the skin lesion and time of year of the incident. L. unguiculata is a small Scyphozoa, approximately 1.5 cm in diameter, and is common in marine waters of the Caribbean, Gulf of Mexico and Western North Atlantic (Florida, Cuba and Bahamas), where there are numerous reports of SBE, which can reach epidemic proportions (Haddad Jr 2008, Rossetto et al. 2009, Haddad Jr et al. 2002. L. unguiculata was identified by Silveira and Morandini (1998a, b) (Haddad Jr et al. 2001). In that same year, Rossetto et al. (2007) observed the first cases of the disease on the north coast of Santa Catarina. This paper presents fourteen cases of the SBE in southern Brazil, and alerts health teams to possible epidemics on the Santa Catarina coast.

MATERIALS AND METHODS
We communicate fourteen cases of seabather's eruption observed in patients in a private practice in the Balneário Camboriú (26° 59 '26 "S 48° 38' 05" W), a town on the northern coast of Santa Catarina, between December 23, 2011 and January 09, 2012.
The sources of information were the medical records of patients with clinical diagnosis of SBE, supplemented with data recorded in a protocol to register cnidarian envenomation (Box 1).

BOX 1
Protocol assessment of incidents with jellyfish.

RESULTS AND DISCUSSION
All the incidents occurred on the north coast of the state of Santa Catarina, in the South region of Brazil. Most of them occurred at Balneário Camboriú beach (78.7%), followed by Laranjeiras Beach (14.2%) in the municipality of Camboriú, and Mariscal Beach (7.1%) in the municipality of Bombas (Table I). These figures reflect the respective numbers of tourists visiting these beaches (www.santur.sc.gov.br).   There was a single episode per victim in all cases, with the exception of a surfer who suffered two episodes on the same beach over a period of 15 days (Balneário Camboriú beach).
Males and female were affected in equal proportion. All the victims were under the age of 15 years, except for one adult. The ages ranged from one to thirty-two years, with an average of nine of age. Children were more commonly affected, suggesting longer exposure to water during bathing, and possibly, more sensitive skin (Haddad Jr et al. 2001, Rossetto et al. 2009).
Most cases (78.5%) reported burning and itching while swimming, which gradually increased in intensity, especially at night. All patients had erythematous papules located in the areas covered by the bathing suits (Figs. 1, 2 and 3). In surfers, the lesions also partially involved the abdomen, chest and thighs (local contact with the surfboard). The diagnosis in all cases was clinical, and no systemic reactions, like malaise, fever, sore throat, abdominal pain, headache, The toxins of cnidarians are composed of a complex mixture of enzymes and peptides with antigenic properties. The ELISA technique enables the demonstration of specific reactivity with IgG antibodies to L. unguiculata in the victims' serum (Burnett et al. 1995). The authors stored the serum of the majority (60.5%) of the thirty-eight victims, for serological tests in the future (Rossetto et al. 2009).
All cases were treated with a combination of systemic antihistamines and topical non-fluorinated corticosteroids.
The use of topical vinegar irreversibly deactivates the nematocysts of L. unguiculata and prevents future discharges, but does not have any effect on already-activated toxins (Kumar et al. 1997, Puertas et al. 2000. The authors found no previous use of vinegar to treat the occurrence in the region. Further studies should be carried out in the region, due to the recent distribution of leaflets sponsored by the 66th Congress of the Brazilian Dermatology Society (SBD) and the General Fire Brigade of Santa Catarina. The pamphlet contains guidelines for treating injuries caused by jellyfish and Portuguese man-of-war, seeking to standardize the first aid given to victims, for whom the lifeguards are usually the first contact. The pamphlet recommends the immediate use of vinegar, at the beach where the incident occurred.
The patients showed good improvement, with the disappearance of symptoms after an average of seven days of treatment, except one case in which the lesions developed to form pustules in the gluteal region, but cleared up after seven days of topical mupirocin.
Due to intense scratching, the disease can progress to secondary bacterial infection in the lesions. The authors observed a surfer who wore neoprene and presented acneiform lesions. Additionally, the planula larvae can penetrate the tissues of most bathing suits, including neoprene (Rossetto et al. 2009). Morandini et al. (2005) reported the presence of L. unguiculata in the form of polyps off the coast of Santa Catarina, at Arvoredo Island Biological Reserve in Florianopolis, near the beaches where the incidents described here occurred. Although the authors have not yet identified the location of the planula larvae of L. unguiculata, plankton collections are currently taking place at Balneário Camboriú beach.
From an epidemiological and clinical perspective, the cases reported are typical: the majority of cases began while bathing in the sea; the victims were mostly younger than 15 years, for whom the exposure period in the water is generally longer than in adults; the dermatitis was manifested by extremely pruritic erythematous papules in the area covered by the bathing suits. The authors emphasize that the incidence of dermatitis in Brazil is probably underestimated because many victims do not seek medical attention (Rossetto et al. 2007(Rossetto et al. , 2009. This is possibly due to high level of spontaneous resolution in two weeks. Moreover, there is a lack of knowledge of the disease among the population and health professionals. The envenomation continued to increase in the region, and thirty-eight cases were published by Rossetto et al. (2009), involving six (42.8%) in fourteen municipalities and eleven (17.2%) of the sixty-four beaches of the North coast of the state of Santa Catarina. Three of these beaches had previous records of incidents by L. unguiculata. In those cases, the diagnosis was made in the first half of January 2012, the same period reported in this paper.

CONCLUSIONS
The authors conclude that the diagnosis of cases in a short period of time, in a localized area where there are high numbers of bathers and tourists at the height of summer season, highlights the growing incidence of the occurrence in the region. The clinical features of the disease should be widely disseminated, as more attention to the problem can show high levels and even future outbreaks of SBE, as recorded in the Gulf of Mexico, the Caribbean and Florida.
Associated with this, the small size of the organisms and the late manifestation of skin irritations, and the correlation between climatic conditions and their occurrence in water, are not as easy to determine as they are other species of jellyfish occurring on the coast of Santa Catarina (Resgalla Jr et al. 2011