The analysis and technical support for this study were done by the Spanish Academy of Dermatology (Research Unit). C. Galv an Casas and A. Catal a contributed equally as first authors.

Background Cutaneous reactions after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines are poorly characterized. Objective To describe and classify cutaneous reactions after SARS-CoV-2 vaccination. Methods A nationwide Spanish cross-sectional study was conducted. We included patients with cutaneous reactions within 21 days of any dose of the approved vaccines at the time of the study. After a face-to-face visit with a dermatologist, information on cutaneous reactions was collected via an online professional

Background: Multiple studies have compared the performance of artificial intelligence (AI)ebased models for automated skin cancer classification to human experts, thus setting the cornerstone for a successful translation of AI-based tools into clinicopathological practice.

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FOSB immunohistochemistry is sensitive in the diagnosis of EH-ALHE, and allows differentiation from its histological mimics. An immunohistochemical panel including not only pan-cytokeratin AE1/AE3 and endothelial markers, but also FOSB, helps in the diagnosis of epithelioid vascular tumors.

We review the most characteristic clinical and histopathologic findings of the cutaneous manifestations of the occlusive nonvasculitic vasculopathic disorders. Clinically, most of these conditions are characterized by retiform purpura. Histopathologic findings consist of occlusion of the vessel lumina with no vasculitis. Different disorders may produce nonvasculitic occlusive vasculopathy in cutaneous blood and lymphatic vessels, including embolization due to cholesterol and oxalate emboli, cutaneous intravascular metastasis from visceral malignancies, atrial myxomas, intravascular angiosarcoma, intralymphatic histiocytosis, intravascular lymphomas, endocarditis, crystal globulin vasculopathy, hypereosinophilic syndrome, and foreign material. Other times, the occlusive disorder is due to platelet pugging, including heparin necrosis, thrombocytosis secondary to myeloproliferative disorders, paroxysmal nocturnal hemoglobinuria, and thrombotic thrombocytopenic purpura. Occlusive vasculopathy may also appear in cold-related gelling agglutination, like that occurring in cryofibrinogenemia, cryoglobulinemia, cold agglutinin syndrome, and crystalglobulinemia. Microorganisms may also occlude the vessels lumina and this is especially frequent in ecthyma gangrenosum, opportunistic fungi as aspergillosis or fusariosis, Lucio phenomenon of lepromatous leprosy and disseminated strongyloidiasis. Systemic coagulopathies due to defects of C and S proteins, coumarin/warfarin-induced skin necrosis, disseminated intravascular coagulation, and antiphospholipid antibody/lupus anticoagulant syndrome may also result in occlusive nonvasculitic vasculopathy. Finally, vascular coagulopathies such as Sneddon syndrome, livedoid vasculopathy, and atrophic papulosis may also cause occlusion of the vessels of the dermis and/or subcutis. Histopathologic study of occlusive vasculopathic lesions is the first step to achieve an accurate diagnosis, and they should be correlated with clinical history, physical examination, and laboratory findings to reach a final diagnosis.

Figure 1 a) Patient 4. Confluent maculopapular exanthem affecting predominantly the trunk and proximal extremities. b) Patient 1. More extensive involvement of the trunk, with areas of unaffected skin. c) HE stain 920. Mild superficial perivascular lympohcytic infiltrate, spongiosis and interface dermatitis. d) HE 940. Mild superficial perivascular lymphocytic infiltrate.

Background A previous study has defined the maculopapular subtype of manifestations of COVID‐19. Objectives To describe and classify maculopapular eruptions associated with COVI‐19. Methods We carried out a subanalysis of the maculopapular cases found in the previous cross‐sectional study. Using a consensus, we defined 7 clinical patterns. We described patient demographics, the therapy received by the patient and the characteristics of each pattern. Results Consensus lead to the description of 7 major maculopapular patterns: Morbilliform (45.5%), Other maculopapular (20.0%), Purpuric (14.2%), Erythema multiforme‐like (9.7%), Pytiriasis rosea‐like (5.7%), Erythema elevatum diutinum‐like (2.3%) and Perifollicular (2.3%). In most cases, maculopapular eruptions were coincident (61.9%) or subsequent (34.1%) to the onset of other COVID‐19 manifestations. The most frequent were cough (76%), dyspnea (72%), fever (88%), and astenia (62%). Hospital admission due to pneumonia was frequent (61%). Drug intake was frequent (78%). Laboratory alterations associated with maculo‐papular eruptions were high C‐reactive protein, high D‐Dimer, lymphopenia, high ferritin, high LDH, and high IL‐6. Limitations The impossibility to define the cause–effect relationship of each pattern. Conclusion We provide a description of the cutaneous maculopapular manifestations associated with COVID‐19. The cutaneous manifestations of COVID‐19 are wide‐ranging and can mimic other dermatoses. This article is protected by copyright. All rights reserved.