Shiitake Dermatitis is a skin eruption that resembles whiplash marks and occurs after consumption of raw shiitake mushrooms. It is caused by a toxic reaction to lentinan, a thermolabil polysaccharide which decomposes upon heating. We report the second case of this dermatitis in Brazil. A 25-year-old man presented with linearly arranged erythematous, pruritic papules on the trunk and limbs, after ingestion of a salad containing raw shiitake mushrooms. The eruption was self-limited, resolving within 10 days of onset. The recognition of this entity gains importance due to the increased consumption of shiitake mushrooms in occidental countries.

FUNDAMENTOS: A síndrome de Sweet (SS) é uma doença rara, caracterizada por lesões cutâneas eritematovioláceas dolorosas, febre, leucocitose com neutrofilia e derme com infiltrado inflamatório neutrofílico denso à histologia. Apresenta excelente resposta à corticoterapia. OBJETIVOS: Avaliar os casos de SS em hospital universitário, identificando as características clínicas, laboratoriais e epidemiológicas e compará-las com os dados da literatura. MÉTODOS: Realizou-se estudo epidemiológico, retrospectivo, mediante revisão de prontuários. Identificaram-se 23 pacientes que preencheram os critérios diagnósticos para a doença no período de março de 1995 a julho de 2009. Coletaram-se dados clínicos e epidemiológicos dos pacientes, tais como: localização das lesões, presença de manifestações cutâneas e extracutâneas, condições associadas à SS e alguns dados laboratoriais, como con tagem de leucócitos e velocidade de hemossedimentação (VHS). RESULTADOS: As idades variaram entre 2 e 75 anos. Houve predomínio do sexo feminino. As lesões acometeram, preferencialmente, tronco e membros superiores. Febre foi a manifestação sistêmica mais comum, seguida por artralgias e mialgia, conjuntivite e artrite. Os fatores desencadeantes mais comumente detectados foram infecções de vias aéreas. Neoplasias associadas ocorreram em 30% dos pacientes, principalmente hematológicas. CONCLUSÕES: Os dados clínicos e epidemiológicos encontrados no presente estudo são, em sua maior parte, similares aos já disponíveis na literatura. Devido à alta prevalência de doenças malignas na SS é importante diagnosticá-la, realizar investigação sistêmica adequada e manter seguimento dos pacientes.

BACKGROUND: Sweet's syndrome or acute febrile neutrophilic dermatosis is a rare disease characterized by painful violaceous erythematous skin lesions, fever, neutrophilic leukocytosis and dense dermal neutrophilic inflammatory infiltrate. It shows excellent response to corticosteroids. OBJECTIVES: To assess cases of Sweet's syndrome in a university hospital, identifying its clinical, laboratory and epidemiological characteristics and compare them with the data found on the literature. METHODS: We conducted a retrospective epidemiological study by examining the medical records of 23 patients who met the diagnostic criteria for the disease from March 1995 to July 2009. We collected clinical and epidemiological data on the patients, such as lesion location, presence of cutaneous and extracutaneous manifestations, conditions associated with SS and some laboratory data, such as leukocyte count and ESR. RESULTS: The age of the patients in the study ranged from 2 to 75 years. There were more females. The lesions mostly affected the trunk and upper limbs. Fever was the most common systemic manifestation, followed by arthralgia and myalgia, conjunctivitis and arthritis. The triggering factors most commonly identified were infections of the respiratory tract. Associated neoplasia occurred in 30% of the patients, especially hematologic neoplasia. CONCLUSION: The clinical and epidemiological data found in our study are mostly similar to those found in the literature. Given the high prevalence of malignant diseases in patients with Sweet's syndrome, it is necessary to know how to perform the diagnosis, carry out a full investigation as well as do the patient's follow up.