Background Janus kinase (JAK) inhibition may be a promising new treatment modality for inflammatory (skin) diseases. However, little is known about direct effects of kinase inhibitors on keratinocyte differentiation and function as well as skin barrier formation. Objective Our aim was to address the direct impact of kinase inhibition of the JAK1/3 pathways by tofacitinib on keratinocyte immune function and barrier formation in atopic dermatitis (AD) and psoriasis. Methods 3D skin equivalents of both diseases were developed and concurrently pretreated with tofacitinib. To induce AD, 3D skin equivalents were stimulated with recombinant human IL‐4 and IL‐13. Psoriasis‐like conditions were induced by incubation with IL‐17A, IL‐22 and tumour necrosis factor α (TNFα). The activation of signal transducer and activator of transcription (STAT)1, STAT3 and STAT6 was assessed by Western blot analysis. Microarray analysis and quantitative real‐time PCR were used for gene expression analysis. Results Tofacitinib pretreatment preserved epidermal morphology and reduced STAT3 and STAT6 phosphorylation of AD‐like and STAT3 phosphorylation of psoriasis‐like culture conditions in 3D skin models compared to sham‐controls. Filaggrin expression was fully maintained in the AD‐like models, but only partially in psoriasis‐like conditions after pretreatment with tofacitinib. In addition, tofacitinib upregulated DSC1, FLG and KRT1. Using gene expression analysis, downregulation of POSTN and IL24 was observed in AD‐like conditions, whereas downregulation of IL20 and IL1B was observed in psoriasis‐like conditions. Conclusion JAK1/3 inhibition counteracted cytokine‐induced AD‐ and psoriasis‐like epidermal morphology and enhanced keratinocyte differentiation in 3D skin models. This effect was more pronounced in the AD‐like models compared to the psoriasis‐like 3D skin models.

As the international refugee crisis has reached new proportions (BMJ, 355, 2016 and i5412), survivors of torture increasingly present in treating physicians with an array of acute or chronic skin lesions. Physicians should be aware of common presentations and likely differential diagnoses in order to avoid mislabelling or under‐recognizing torture. Survivors of torture also frequently suffer from psychological sequelae, such as post‐traumatic stress disorder, and appropriate referrals are essential in order to improve recovery trajectory. Skin sequelae are the most common physical findings of torture. Not all skin lesions seen in tortured survivors are due to perpetrator inflicted injuries, and many dermatological conditions can mimic lesions typical of torture, as can scars as a result of folk remedies or cultural practices specific to geographical regions. Medical documentation of torture includes injury and lesion description. While forensic dermatology and other forensic specialties use an injury description taxonomy, and the standard dermatologic taxonomy uses an anatomic description, they are complementary sciences for lesions inflicted by torture. This results in an opportunity for learning across disciplines in order to improve evidence documentation for survivors of torture. This article describes features of common skin lesions consistent with torture, including their clinical appearances, differential diagnoses, patterns of injury and appropriate clinical descriptions.

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