There is growing evidence that not only the novel coronavirus disease (COVID‐19) but also the COVID‐19 vaccines can cause a variety of skin reactions. In this review article, we provide a brief overview on cutaneous findings that have been observed since the emerging mass COVID‐19 vaccination campaigns all over the world. Unspecific injection‐site reactions very early occurring after the vaccination are most frequent. Type I hypersensitivity reactions (e.g. urticaria, angio‐oedema and anaphylaxis) likely due to allergy to ingredients may rarely occur but can be severe. Type IV hypersensitivity reactions may be observed, including delayed large local skin lesions (“COVID arm”), inflammatory reactions in dermal filler or previous radiation sites or even old BCG scars, and more commonly morbilliform and erythema multiforme‐like rashes. Autoimmune‐mediated skin findings after COVID‐19 vaccination include leucocytoclastic vasculitis, lupus erythematosus and immune thrombocytopenia. Functional angiopathies (chilblain‐like lesions, erythromelalgia) may also be observed. Pityriasis rosea‐like rashes and reactivation of herpes zoster have also been reported after COVID‐19 vaccination. In conclusion, there are numerous cutaneous reaction patterns that may occur following COVID‐19 vaccination, whereby many of these skin findings are of immunological/autoimmunological nature. Importantly, molecular mimicry exists between SARS‐CoV‐2 (e.g. the spike‐protein sequences used to design the vaccines) and human components and may thus explain some COVID‐19 pathologies as well as adverse skin reactions to COVID‐19 vaccinations.

Hidradenitis suppurativa (HS) is a chronic inflammatory disease manifesting in inverse body regions. In a systematic review, the role of hormones in HS will be presented to better understand the pathomechanisms of HS. The review is based on the PRISMA criteria. Systematic research was carried out using keywords. Subsequently, the data were analyzed based on the clinical response and other relevant information. The main focus of our systematic review was on HS manifestation, exacerbation, sex hormones, antiandrogen therapy, thyroid function, polycystic ovary syndrome, insulin resistance, and adipokines. In HS, there appears to be a dysregulated adipokine release that is shifted towards pro-inflammatory adipokines. Insulin resistance is significantly more common in HS than in healthy patients regardless of BMI, age, and gender. Insulin resistance in HS patients leads to further cardiovascular disease. The mechanism of insulin resistance and role of adipokines should be investigated in future studies to better provide the pathomechanisms of HS. The role of androgens seems to be important in a certain subgroup of female patients. Anti-androgenic therapy can be useful and helpful in some patients. However, further studies are needed to better understand the hormonal relationship in HS.

Chronic wounds (CWs) pose a significant health challenge in clinical practice. Standard wound therapy (SWT) is currently considered the gold standard. However, recent evidence suggests that cold plasma therapy (CPT) holds promise for improving CWs. In light of this, the POWER study was conducted as a multicenter, randomized clinical trial to investigate the effect of large-area plasma application compared with SWT in patients with chronic, non-healing arterial or venous wounds on the lower leg. To analyze the interim results, we employed a comprehensive range of statistical tests, including both parametric and non-parametric methods, as well as GLS model regression and an ordinal mixed model. Our findings clearly demonstrate that CPT therapy significantly accelerates wound closure compared with SWT. In fact, complete wound closure was exclusively observed in the CPT group during the intervention period. Additionally, the CPT group required significantly less antibiotic therapy (4%) compared with the SWT group (23%). Furthermore, CPT led to a significant reduction in wound pain and improved quality of life compared with SWT. In conclusion, the study highlights that the combination of CPT and SWT surpasses monotherapy with SWT alone.

Background: Hidradenitis suppurativa (HS) is a relatively common chronic inflammatory condition of intertriginous skin. In recent years, the neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), monocyte/lymphocyte ratio (MLR) and platelet/neutrophil ratio (PLR) have been shown to be indicators of systemic inflammation correlating with severity of inflammatory conditions.Objectives: We aimed to analyse for the first time the systemic inflammation biomarkers also including the pan‐immune‐inflammation value (PIV) and the systemic immune‐inflammation index (SII) in HS patients and controls.Methods: This study retrospectively investigated clinical and laboratory data of 142 patients with HS. Moreover, a sex‐age‐matched healthy control group was included. The severity of HS was routinely assessed by the Hurley staging, the mHSS and the SAHS score. All inflammation‐based biomarkers were calculated from absolute values of complete blood counts. Receiver‐operating characteristics analyses, including the Youden index, were performed in order to determine optimal cut‐off values and test performance.Results: Whereas PIV and SII were significantly higher in HS patients, PLR, MLR and PNR were significantly lower in HS patients when compared to controls. Almost all inflammation‐based biomarkers significantly correlated with disease severity. However, PIV was the only test that was significantly associated with HS severity as indicated by a Youden index of 0.56 (associated criterion: 756.4; AUC: 0.79, P < 0.0001).Conclusions: Although all systemic inflammation‐based biomarkers investigated are more or less associated with HS severity, the PIV appears to have the best performance in this regard. It may be employed in adjunction with the clinical scores for treatment decision making or clinical trial assessments.

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease presenting with recurrent inflammatory lesions in intertriginous body regions. HS has a pronounced impact on patients’ quality of life and is associated with a variety of comorbidities. Treatment of HS is often complex, requiring an individual approach with medical and surgical treatments available. However, especially in moderate-to-severe HS, there is an urgent need for new treatment approaches. In recent years, increased research has led to the identification of new potential therapeutic targets. This review aims to give a comprehensive and practical overview of current treatment options for HS. Furthermore, the clinically most advanced novel treatment approaches will be discussed.

Purpose: We aimed to determine whether the pan-immune-inflammation value (PIV) of patients with Merkel cell carcinoma (MCC) at primary diagnosis differs from controls and whether it is associated with disease stage and outcome. Methods: In this retrospective study, we recruited MCC patients with stage I–III. PIV was calculated from absolute complete blood cell counts obtained within one week at MCC diagnosis as follows: [neutrophils (10³/mm³) × platelets (10³/mm³) × monocytes (10³/mm³)]/lymphocytes (10³/mm³). As controls, we studied age–gender-matched cutaneous melanoma (CM, stage I–III) patients and healthy controls (HC). Univariate and multivariate statistics were used. Results: The median PIV in MCC patients was significantly increased compared to both CM patients as well as healthy controls. PIV of MCC patients in stage II and III was significantly higher compared to stage I patients. ROC analysis revealed that MCC recurrence was significantly associated with a PIV greater than 372 [p < 0.0001, Youden index 0.58; hazard ratio: 4 (95% confidence interval: 1.7 to 9.2)]. In multivariate analysis, only a PIV greater than 372 and higher MCC stage were determined as independent predictors for disease recurrence. Conclusion: We determined, for the first time, the prognostic ability of the promising blood-based biomarker PIV in MCC patients and observed that PIV is increased in MCC patients in dependence on disease stage and independently predicts MCC recurrence.