Letter to the Editor COVID-19 infection in the differential diagnosis of retiform purpura. 10

Background: Data on the clinical patterns and histopathology of SARS-CoV-2 related skin lesions, as well as on their relationship with the severity of COVID-19 are limited. Methods and Materials: Retrospective analysis of a prospectively collected cohort of patients with SARS-CoV-2 infection in a teaching hospital in Barcelona, Spain, from 1 April to 1 May 2020. Clinical, microbiological and therapeutic characteristics, clinicopathological patterns of skin lesions, and direct immunofluorescence and immunohistochemical findings in skin biopsies were analyzed. Results: Fifty-eight out of the 2761 patients (2.1%) either consulting to the emergency room or admitted to the hospital for COVID-19 suspicion during the study period presented COVID-19 related skin lesions. Cutaneous lesions could be categorized into six patterns represented by the acronym “GROUCH”: Generalized maculo-papular (20.7%), Grover’s disease and other papulo-vesicular eruptions (13.8%), livedo Reticularis (6.9%), Other eruptions (22.4%), Urticarial (6.9%), and CHilblain-like (29.3%). Skin biopsies were performed in 72.4%, including direct immunofluorescence in 71.4% and immunohistochemistry in 28.6%. Patients with chilblain-like lesions exhibited a characteristic histology and were significantly younger and presented lower rates of systemic symptoms, radiological lung infiltrates and analytical abnormalities, and hospital and ICU admission compared to the rest of patients. Conclusion: Cutaneous lesions in patients with COVID-19 appear to be relatively rare and varied. Patients with chilblain-like lesions have a characteristic clinicopathological pattern and a less severe presentation of COVID-19.

Background. Monitoring of disease activity in sclerosing dermatoses (SD) can be challenging and tools to support clinical decision-making are lacking. Aim. To analyse the impact of high-frequency ultrasonography (HFUS) on the clinical management of SD and to describe the US characteristics of disease activity. Methods. This was a cohort study of patients with various SD [morphoea, systemic sclerosis (SS) and chronic graft-versus-host disease (cGvHD)] who underwent HFUS between January 2017 and August 2019. HFUS criteria for diagnosing active SD were increased Doppler vascularity and/or meeting all B-mode greyscale US signs of activity. Discordance in SD activity between HFUS and clinical examination was evaluated at the time of the first US assessment. Changes in patient management were instituted after HFUS were recorded. Results. In total, 72 patients (31 with morphoea, 19 with SS and 22 with cGvHD), who underwent 163 HFUS sessions in total, were included. All HFUS-active morphoea lesions exhibited increased vascularity, and all HFUS-active SS exhibited dermal thickening and dermal hypoechogenicity. HFUS-active cGvHD displayed increased dermal thickness and loss of definition of the dermal-hypodermal junction, and there were signs of panniculitis in 80% of cases and of increased vascularity in 70%. Discordance in disease activity between clinical and HFUS evaluation was found in 17 (23.6%) patients. Changes in clinical management after HFUS were made for 14 (19.4%) patients: treatment discontinuation for 6 patients (42.9%), treatment initiation for 5 (35.7%), medication change for 2 (14.3%) and skin biopsy taken for 1 (7.1%). Conclusion. HFUS seems an efficacious support tool in the monitoring of SD activity with a notable impact on clinical management. Further studies are warranted to evaluate the impact of HFUS-supported management changes on SD outcomes.

Several studies have suggested that naevus-associated melanomas differ from de novo melanomas, being thinner and with less ulceration; however, the prognostic implication is unclear. The objective of this study was to describe clinicopathological, genetic and survival characteristics of de novo and naevus-associated melanomas in a cohort of primary invasive cutaneous melanomas over a 20-year period. Of the 2,227 patients included in the study, 509 (22.86%) had naevus-associated melanomas. Compared with patients with de novo melanoma, they were younger, with a fairer phototype and a higher naevus count, tumours were predominantly the superficial spreading subtype, American Joint Committee on Cancer stage I, located on the trunk, and there were fewer signs of invasiveness (thinner Breslow index, less ulceration, lower mitotic index and less satellitosis). Germline mutational status did not show any significant association. As determined through univariate analysis, overall survival was significantly better in patients with naevus-associated melanoma (hazard ratio 0.64; 95% confidence interval 0.51–0.80, p < 0.001), but multivariate analysis did not support this prognostic indication (hazard ratio 0.94; 95% confidence interval 0.75–1.18, p < 0.606). Despite this, we conclude that naevus-associated and de novo melanomas should be considered as different subtypes of melanoma.