The pandemic condition Coronavirus‐disease (COVID‐19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) can take asymptomatic, mild, moderate, and severe courses. COVID‐19 affects primarily the respiratory airways leading to dry cough, fever, myalgia, headache, fatigue, and diarrhea and can end up in interstitial pneumonia and severe respiratory failure. Reports about the manifestation of various skin lesions and lesions of the vascular system in some subgroups of SARS‐CoV‐2 positive patients as such features outside the respiratory sphere, are rapidly emerging. Vesicular, urticarial and maculopapular eruptions as well as livedo, necrosis and other vasculitis forms have been reported most frequently in association with SARS‐CoV‐2 infection. In order to update information gained, we provide a systematic overview of the skin lesions described in COVID‐19 patients, discuss potential causative factors and describe differential diagnostic evaluations. Moreover, we summarize current knowledge about immunologic, clinical and histologic features of virus‐ as well as drug‐induced lesions of the skin and changes to the vascular system in order to transfer this knowledge to potential mechanisms induced by SARS‐CoV‐2.

The development of cancer immunotherapy and targeted therapy has reached an important inflection point in the history of melanoma. Immune checkpoint inhibitors and kinase inhibitors are today’s standard of care treatments in advanced melanoma patients. Treatment-related toxicities can be very intriguing and quite challenging. Sarcoidosis is a multisystemic granulomatous disease characterized by an aberrant immune response to unknown antigens, whereas sarcoid-like reactions (SLRs) refer to localized clinical features. We carried out a single-center observational study in patients with stage IIB–IV melanoma treated with BRAF/MEK inhibitors and immune checkpoint inhibitors. A description of the sarcoidosis-related manifestations was provided from patients’ records. We observated eight cases of SLRs in a cohort of 200 patients. The clinical courses were characterized by a variety of symptoms, accompanied by cutaneous signs and extracutaneous manifestations such as bilateral, hilar lymphadenopathy. We identified a histologically granulomatous inflammation involving the skin, the lungs, and the lymph nodes. Two patients presented with cutaneous lesions only, and three patients had lung involvement only. Three patients achieved complete and partial response of the melanoma disease, and three patients had stable disease. Disease progression was documented in two patients. The reported immune-related adverse events were mild to severe and in most of the cases were continued without any treatment cessation. SLRs appear during treatment with both kinase and immune checkpoint inhibitors. Awareness of these can avoid misdiagnosis of disease progression and unnecessary treatment changes.

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