Hidradenitis suppurativa (HS)/acne inversa is a debilitating chronic disease that remains poorly understood and difficult to manage. Clinical practice is variable, and there is a need for international, evidence‐based and easily applicable consensus on HS management. We report here the findings of a systematic literature review, which were subsequently used as a basis for the development of international consensus recommendations for the management of patients with HS. A systematic literature review was performed for each of nine clinical questions in HS (defined by an expert steering committee), covering comorbidity assessment, therapy (medical, surgical and combinations) and response to treatment. Included articles underwent data extraction and were graded according to the Oxford Centre for Evidence‐based Medicine criteria. Evidence‐based recommendations were then drafted, refined and voted upon, using a modified Delphi process. Overall, 5310 articles were screened, 171 articles were analysed, and 65 were used to derive recommendations. These articles included six randomized controlled trials plus cohort studies and case series. The highest level of evidence concerned dosing recommendations for topical clindamycin in mild disease (with systemic tetracyclines for more frequent/widespread lesions) and biologic therapy (especially adalimumab) as second‐line agents (following conventional therapy failure). Good‐quality evidence was available for the hidradenitis suppurativa clinical response (HiSCR) as a dichotomous outcome measure in inflammatory areas under treatment. Lower‐level evidence supported recommendations for topical triclosan and oral zinc in mild‐to‐moderate HS, systemic clindamycin and rifampicin in moderate HS and intravenous ertapenem in selected patients with more severe disease. Intralesional or systemic steroids may also be considered. Local surgical excision is suggested for mild‐to‐moderate HS, with wide excision for more extensive disease. Despite a paucity of good‐quality data on management decisions in HS, this systematic review has enabled the development of robust and easily applicable clinical recommendations for international physicians based on graded evidence.

The ability of bacteria to aggregate and form biofilms impairs phagocytosis by polymorphonuclear leukocytes (PMNs). The aim of this study was to examine if the size of aggregates is critical for successful phagocytosis and how bacterial biofilms evade phagocytosis. We investigated the live interaction between PMNs andPseudomonas aeruginosa,Staphylococcus aureus,Escherichia coliandStaphylococcus epidermidisusing confocal scanning laser microscopy. Aggregate size significantly affected phagocytosis outcome and larger aggregates were less likely to be phagocytized. Aggregates ofS. epidermidiswere also less likely to be phagocytized than equally-sized aggregates of the other three species. We found that only aggregates of approx. 5 μm diameter or smaller were consistently phagocytosed. We demonstrate that planktonic and aggregated cells of all four species significantly reduced the viability of PMNs after 4 h of incubation. Our results indicate that larger bacterial aggregates are less likely to be phagocytosed by PMNs and we propose that, if the aggregates become too large, circulating PMNs may not be able to phagocytose them quickly enough, which may lead to chronic infection.

Importance Biologics are important in treating patients with hidradenitis suppurativa (HS). However, to our knowledge, data on their real-life performance and treatment patterns in HS are limited. Objective To examine the drug survival of biologic therapies for HS in a real-world setting. Design, Setting, and Participants This cohort study included all patients with HS between January 1, 2005, and December 31, 2018, who were treated with biologics at the 5 academic hospital clinics where all biologic treatment for HS is conducted in Denmark. Biologics included adalimumab, anakinra, certolizumab pegol, etanercept, golimumab, infliximab, secukinumab, and ustekinumab. Data were analyzed between June 1, 2021, and June 20, 2021. Main Outcomes and Measures Drug survival was depicted through Kaplan-Meier curves, and Cox regression models were used to calculate adjusted (age, sex, previous number of biologic treatment series) hazard ratios (aHRs) with 95% CIs for the risk of treatment discontinuation. Switching patterns were visualized through a Sankey diagram. Results The study comprised 241 patients (176 women [61.8%]; total of 386 treatment series) with a mean (SD) age of 41.8 (12.6) years at initiation of first biologic therapy. There were a total of 256 (189 [73.8%] biologic naive), 66 (32 [48.5%] biologic naive), 23 (9 [39.1%] biologic naive), and 22 (9 [40.9%] biologic naive) treatment series with adalimumab, infliximab, etanercept, and ustekinumab, respectively. The median time to discontinuation was 36.0 (IQR, 21.9-63.0), 28.7 (IQR, 15.1-62.9), 26.0 (IQR, 16.9-155.9), and 17.9 weeks (IQR, 12.9-41.0) for adalimumab, infliximab, ustekinumab and etanercept, respectively. The risk of drug discontinuation was significantly higher for etanercept compared with adalimumab (aHR, 1.81; 95% CI, 1.16-2.82), infliximab (aHR, 1.77; 95% CI, 1.03-3.05), and ustekinumab (aHR, 2.49; 95% CI, 1.12-5.52), whereas no difference was observed when comparing these 3 therapies with each other. We found no significant differences in drug survival for biologic-naive vs nonnaive treatment series. Increasing C-reactive protein levels (aHR, 1.01; 95% CI, 1.00-1.03) and concomitant antibiotic treatment (aHR, 2.82; 95% CI, 1.36-5.86) were associated with the risk of discontinuing infliximab therapy. Men (aHR, 0.69; 95% CI, 0.51-0.91) had a reduced risk of discontinuing use of adalimumab. Conclusions and Relevance In this cohort study, drug survival was comparable between adalimumab, infliximab, and ustekinumab but significantly lower for etanercept. There were no differences in drug survival among biologic-naive and nonnaive patients.

Background:Sarcoptes scabiei can be visualized with different imaging tools. Optical coherence tomography (OCT) may have the potential to describe the changes in skin morphology due to scabies infestation and visualize the parasite. Methods: Five patients from the Departments of Dermatology, Augsburg, Germany, and Roskilde, Denmark, were OCT scanned (VivoSight®; Michelson Diagnostics Ltd., UK). Mites were identified by epiluminescence and light microscopy to confirm the diagnosis. Results: OCT identified S. scabiei mites in all patients in vivo. Mites and burrows were visualized, and some detail on burrow content was provided. Conclusion: OCT can visualize S. scabiei mites in vivo, suggesting that it may be used to study the biology of the mites in vivo and provide early assessment of scabicide therapy. OCT is able to visualize structures in the skin with an 8-µm resolution. Therefore, this technology could potentially allow rapid, non-invasive, in vivo diagnosis and analysis of infestations.