Seborrheic dermatitis is a chronic relapsing erythematous scaly skin disease, the prevalence of which is around 1 to 3% of the general population in the United States. It has two incidence peaks, the first in the first three months of life and the second beginning at puberty and reaching its apex at 40 to 60 years of age. The prevalence of seborrheic dermatitis is higher in HIV-positive individuals and the condition tends to be more intense and refractory to treatment in these patients. Neurological disorders and other chronic diseases are also associated with the onset of seborrheic dermatitis. The currently accepted theory on the pathogenesis of this disease advocates that yeast of Malassezia spp., present on the skin surface of susceptible individuals, leads to a non-immunogenic irritation due to the production of unsaturated fatty acids deposited on the skin surface. This article provides a review of the literature on seborrheic dermatitis, focusing on immunogenetics, the clinical forms of the disease and its treatment. . Keywords: Dermatitis; Dermatitis, seborrheic; Eczema Resumo: A dermatite seborreica é uma doença eritêmato-escamativa de caráter crônico-recidivante que acomete entre 1 e 3% da população geral dos Estados Unidos. Possui dois picos de incidência -o primeiro, durante os três primeiros meses de vida, e o segundo, a partir da puberdade, atingindo seu ápice entre os 40 e 60 anos de idade. Os indivíduos HIV positivos têm maior prevalência da doença, que apresenta maior intensidade e tendência à refratariedade ao tratamento. Doenças neurológicas e outras doenças crônicas também estão associadas ao desenvolvimento da dermatite seborreica. Como mecanismo fisiopatogênico, reconhece-se que o fungo Malassezia sp., presente na pele de indivíduos suscetíveis, leve a uma irritação não-imunogênica a partir da produção de metabólitos à base de áci-dos graxos insaturados deixados na superfície cutânea. Este artigo faz uma revisão da literatura sobre dermatite seborreica, com ênfase nos aspectos imunogenéticos, formas clínicas e tratamento.

Childhood linear immunoglobulin A dermatosis is a rare autoimmune vesiculobullous disease. It results in linear deposition of autoantibodies (immunoglobulin A) against antigens in the basal membrane zone, leading to subepidermal cleavage. Additional depositions of immunoglobulin G and complement-3 might occur. It is still debated whether concomitant findings of immunoglobulins A and G should be considered a subtype of this dermatosis or a new entity. Further studies are needed to recognize this clinical variant.

Linear IgA dermatosis has been increasingly associated with inflammatory bowel diseases, particularly ulcerative colitis. A 13-year-old male patient with an 11-month history of ulcerative colitis developed vesicles, pustules and erosions on the skin of the face, trunk and buttocks and in the oral mucosa. The work-up revealed a neutrophil-rich sub-epidermal bullous disease and linear deposition of IgA along the dermoepidermal junction, establishing the diagnosis of linear IgA dermatosis. The patient experienced unsatisfactory partial control of skin and intestinal symptoms despite the use of adalimumab, mesalazine, prednisone and dapsone for some months. After total colectomy, he presented complete remission of skin lesions, with no need of medications during two years of follow-up. A review of previously reported cases of the association is provided here and the role of ulcerative colitis in triggering linear IgA dermatosis is discussed.

Prurigo pigmentosa (PP) is a rare inflammatory disease of the skin of uncertain etiology first reported in Japan. It is typified by recurrent eruptions of itching urticarial macules, papules, vesicopapules, and plaques with a reticular arrangement that quickly resolve leaving a net-like pigmentation. The disease presents specific histopathological features. Herein, 3 cases of PP in Brazilians with no Japanese ancestry are reported and a revision of all previous English-language case reports indexed on PubMed is provided. Two articles with original case reports not listed on PubMed were also included. Our patients are 2 women and 1 man at the ages of 39, 33, and 22 years, respectively. All 3 presented findings in consonance with previous cases of PP and were diagnosed based on clinicopathological correlation. They were successfully treated with oral minocycline or doxycycline. In our literature review, a total of 210 previously reported cases were included. Although PP seemed to be restricted to Japanese patients in the first years after its recognition, the geographic boundaries of the disease are continuously expanding. Korea responded for 83 previous cases and Japan for 53. The mean age was 24.4 years, with 84.3% of the cases occurring between 11 and 30 years of age. The female/male rate was 2.6 and the most affected anatomical sites were back, chest, and neck. We do believe that the rarity of case reports in western countries may represent lack of awareness about the disease by dermatologists and dermatopathologists in these regions.

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