Background: Urticarial vasculitis (UV) should be differentiated from chronic spontaneous urticaria (CSU) in patients initially presenting with recurrent wheals, although criteria for differential diagnosis remain ill‐defined.Objectives: To set the goals, define criteria and unmet needs in UV diagnosis and differential diagnosis with CSU, and explore the possibility of coexistence of both diseases.Methods: Thirteen experts experienced in UV research participated in a Delphi survey of European Academy of Allergy and Clinical Immunology taskforce. This Delphi survey involved three rounds of anonymous responses ton = 32 questions with the aim to aggregate the experts' opinions and to achieve consensus. Urticaria specialists (n = 130, most from Urticaria Centers of Reference and Excellence) evaluated the consensus statements and recommendations in the fourth and final round.Results: The panel agreed that essential criteria to guide a skin biopsy in patients with recurrent wheals should include at least one of the following features: wheal duration >24 h, bruising/postinflammatory hyperpigmentation, and systemic symptoms. Leukocytoclasia and fibrin deposits were identified as a minimum set of UV histological criteria. As agreed by the panel members, CSU and normocomplementemic UV (NUV) may coexist in some patients.Conclusions: The use of established criteria for the diagnosis and differential diagnosis of UV in patients with recurrent wheals can help guide the diagnostic approach and prompt earlier treatment. Further studies should investigate whether CSU and NUV are different entities or part of a disease spectrum.

Introdução: A COVID-19, doença infeciosa causada por um novo coronavírus, SARS-CoV-2, propagou-se rapidamente pelo mundo inteiro, resultando numa necessidade emergente de obtenção de conhecimentos alusivos à sua patogénese, diagnóstico e sintomatologia. Mais especificamente, um número cada vez maior de casos relativos a manifestações cutâneas, previamente desconhecidas, tem vindo a ser descrito.Material e Métodos: Foi realizada uma pesquisa de literatura, através da base de dados PubMed, referente às manifestações dermatológicas associadas à COVID-19. O presente artigo descreve os achados clínicos e histológicos das principais lesões cutâneas observadas em contexto da infeção por SARS-CoV-2.Discussão: Manifestações cutâneas associadas à COVID-19 foram descritas em múltiplos estudos retrospetivos e prospetivos, séries de casos e casos clínicos isolados. A incidência reportada atingiu os 20,4%, verificando-se uma heterogeneidade de padrões clínicos substancial. Destes destacam-se as erupções eritematosas/maculopapulares, urticariformes, papulovesiculares, purpúricas/petequiais, lesões tipo-perniose e lesões livedóides/acro-isquémicas. O conhecimento dos mecanismos fisiopatológicos subjacentes tem vindo a ser enriquecido com achados os histológicos e de biologia molecular.Conclusão: É essencial o reconhecimento das manifestações dermatológicas associadas à COVID-19, uma vez que podem permitir o diagnóstico precoce da infeção, nomeadamente em casos oligossintomáticos ou quando não é possível a realização de testes confirmatórios. Embora menos estabelecido, lesões tipo-perniose e acro-isquémicas, parecem ter também um papel importante a nível prognóstico.

Patients submitted to radiotherapy for tinea capitis in childhood have an increased incidence of scalp basal cell carcinomas (BCCs) but also of other neoplasms, namely, follicular tumors. In a cohort of such patients, we also found a high incidence of infundibulocystic BCCs, an otherwise rare variant. We thus hypothesized that postradiotherapy BCCs could be more prone to display follicular differentiation. We compared the histological and immunohistochemical features of postradiotherapy BCCs [both conventional (16 cases) and infundibulocystic (16 cases)] with those of BCCs arising in sun-exposed areas (16 cases), using markers of follicular differentiation (PHLDA-1, CK15, CD34, β-catenin, and calretinin). Postradiotherapy BCCs showed slightly higher tendency for infundibular and/or trichilemmal differentiation than BCCs from sun-exposed areas (37.5% vs. 18.8%), but this difference was not statistically significant. Nevertheless, infundibulocystic BCCs showed more frequent expression of PHLDA-1 and stronger cytoplasmic expression of CK15 compared with the other lesions. In addition, CD34 highlighted a characteristic meshwork of stromal cells surrounding the epithelial component in all infundibulocystic BCCs, in contrast to the other postradiotherapy BCCs and UV-related BCCs, in which 78.1% were negative or only focally positive. In conclusion, our study suggests a tendency for more frequent follicular differentiation in postradiotherapy BCCs compared with BCCs from sun-exposed areas. In addition, the immunohistochemical study confirms previous data from the literature regarding infundibulocystic BCCs (higher CK15 and PHLDA-1 expression) and shows a distinctive stromal positivity for CD34 that has not been previously acknowledged in these tumors.