Seabathers eruption is an intensely pruriginous form of dermatitis that occurs after contact with the planula larvae of the cnidarian scyphozoan Linuche unguiculata, especially under the bathers clothes. They discharge their poisonous nematocysts from the cnidocytes, causing a typical eruption presenting papules, erythema and intense itching. The first five cases described in Brazil were published in 2001 and occurred on the southeastern coast (Ubatuba, State of São Paulo). Those cases were linked to larvae of Linuche unguiculata, because the occurrence and life cycle of this cnidarian had been studied in the São Sebastião Channel, State of São Paulo. The present authors report the six cases observed in southern Brazil (State of Santa Catarina), with a description of the typical clinical aspects and an investigation linking the cases to Linuche unguiculata in the local seawater.