Summary The current COVID‐19 pandemic is caused by the SARS‐CoV‐2 coronavirus. The initial recognized symptoms were respiratory, sometimes culminating in severe respiratory distress requiring ventilation, and causing death in a percentage of those infected. As time has passed, other symptoms have been recognized. The initial reports of cutaneous manifestations were from Italian dermatologists, probably because Italy was the first European country to be heavily affected by the pandemic. The overall clinical presentation, course and outcome of SARS‐CoV‐2 infection in children differ from those in adults as do the cutaneous manifestations of childhood. In this review, we summarize the current knowledge on the cutaneous manifestations of COVID‐19 in children after thorough and critical review of articles published in the literature and from the personal experience of a large panel of paediatric dermatologists in Europe. In Part 1, we discuss one of the first and most widespread cutaneous manifestation of COVID‐19, chilblain‐like lesions. In Part 2, we review other manifestations, including erythema multiforme, urticaria and Kawasaki disease‐like inflammatory multisystemic syndrome, while in Part 3, we discuss the histological findings of COVID‐19 manifestations, and the testing and management of infected children, for both COVID‐19 and any other pre‐existing conditions.

Summary The current COVID‐19 pandemic is caused by the SARS‐CoV‐2 coronavirus. The initial recognized symptoms were respiratory, sometimes culminating in severe respiratory distress requiring ventilation, and causing death in a percentage of those infected. As time has passed, other symptoms have been recognized. The initial reports of cutaneous manifestations were from Italian dermatologists, probably because Italy was the first European country to be heavily affected by the pandemic. The overall clinical presentation, course and outcome of SARS‐CoV‐2 infection in children differ from those in adults, as do the cutaneous manifestations of childhood. In this review, we summarize the current knowledge on the cutaneous manifestations of COVID‐19 in children after thorough and critical review of articles published in the literature and from the personal experience of a large panel of paediatric dermatologists in Europe. In Part 1, we discussed one of the first and most widespread cutaneous manifestations of COVID‐19, chilblain‐like lesions. In this part of the review, we describe other manifestations, including erythema multiforme, urticaria and Kawasaki disease‐like inflammatory multisystemic syndrome. In Part 3, we discuss the histological findings of COVID‐19 manifestations, and the testing and management of infected children for both COVID‐19 and any other pre‐existing conditions.

Summary The current COVID‐19 pandemic is caused by the SARS‐CoV‐2 coronavirus. The initial recognized symptoms were respiratory, sometimes culminating in severe respiratory distress requiring ventilation, and causing death in a percentage of those infected. As time has passed, other symptoms have been recognized. The initial reports of cutaneous manifestations were from Italian dermatologists, probably because Italy was the first European country to be heavily affected by the pandemic. The overall clinical presentation, course and outcome of SARS‐CoV‐2 infection in children differ from those in adults as do the cutaneous manifestations of childhood. In this review, we summarize the current knowledge on the cutaneous manifestations of COVID‐19 in children after thorough and critical review of articles published in the literature and from the personal experience of a large panel of paediatric dermatologists in Europe. In Part 1, we discuss one of the first and most widespread cutaneous manifestations of COVID‐19, chilblain‐like lesions, and in Part 2 we expanded to other manifestations, including erythema multiforme, urticaria and Kawasaki disease‐like inflammatory multisystemic syndrome. In this part of the review, we discuss the histological findings of COVID‐19 manifestations, and the testing and management of infected children for both COVID‐19 and any other pre‐existing conditions.

Background and objectives: Psoriasis is a chronic immune-mediated skin disease caused by several complex factors, both environmental and genetic, many of which are still not fully understood. Nowadays, several groups of biological drugs are being used for psoriasis treatment. Although these therapies are very effective, they show significant variability in efficacy among individuals. Therefore, there is a need for biomarkers to predict treatment outcomes in order to guide personalized therapeutic decisions. Pharmacogenetics is the study of variations in DNA sequences related to drug response. Materials and Methods: In this article, we review pharmacogenetics studies on the treatment of moderate-to-severe psoriasis focusing on anti-interleukin (IL) 12/23 (ustekinumab) and anti-IL17 drugs (secukinumab and ixekizumab), as well as recent studies concerning anti-TNF drugs. Results: Several polymorphisms have been studied over the years in reference to anti-TNF drugs; some of the most recent studies included the performance of a genome-wide association study (GWAS) and pharmacogenetics studies focused on the optimization of a treatment regimen. Various polymorphisms in different genes have been related to ustekinumab response; among them, the most commonly studied is the HLA-C*06:02 allele. Conclusions: Although not confirmed in some studies, most studies have shown that patients carrying this allele present a significantly higher response rate to ustekinumab. Some polymorphisms have been studied in patients treated with anti-IL17 drugs, mostly related to secukinumab; however, up to now, no association has been found between any of these polymorphisms and response. Nevertheless, further studies involving larger cohorts are needed in order to confirm these results before the implementation of this biomarker in clinical practice.

Correspondence disseminated forms of other common viral infections and also rarer entities such as pseudovesicular GD, as these two cases seem to be.