Abstract Mosquito-borne viruses are inoculated into skin, yet how environmental exposures shape susceptibility remains unclear. We identify ultraviolet (UV) exposure as an unrecognised determinant of mosquito-borne virus infection. In mice, prior UV exposure increased Semliki Forest virus replication, viraemia and mortality, and also enhanced Zika virus infection. Early susceptibility was driven by recruited CCR2-dependent myeloid cells that were preferentially infected and amplified virus. This phase was transient: by one week, infection shifted toward proliferating fibroblasts within repairing skin, accompanied by a glycolytic tissue signature. In primary human dermal fibroblasts, viral replication was governed by metabolic state rather than proliferation alone, suggesting that repair-associated metabolic reprogramming underlies stromal permissiveness. Topical steroids partially alleviated UV-conditioned enhancement of virus susceptibility. UV also warmed skin and increased mosquito probing. Together, these findings establish UV exposure as a driver of conditioned states that determine arbovirus susceptibility, identifying sunlight as a modifiable determinant of vector-borne disease risk. In Brief / eTOC blurb McCafferty-Brown et al. show that ultraviolet exposure conditions skin to enhance mosquito-borne virus infection. Susceptibility shifts from infected myeloid cells early after UV to proliferating fibroblasts with a glycolytic tissue signature during repair, while UV-exposed skin also increases Aedes aegypti probing.

Abstract Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by pruritus and recurrent eczematous lesions. These features contribute to sleep disturbances and reduced quality of life. A single-centre retrospective chart review was carried out to assess potential differences in treatment response by disease phenotype. Patients with newly diagnosed AD (n = 109) were categorized into four subgroups: severe itch–severe lesion (SI-SL, itch > 6/EASI > 21), severe itch–mild/moderate lesion (SI-ML, itch > 6/EASI ≤ 21), moderate itch–severe lesion (MI-SL, itch ≤ 6/EASI > 21) and mild/moderate itch–mild/moderate lesion (MI-ML, itch ≤ 6/EASI ≤ 21). Itch severity was determined by Peak Pruritus Numerical Rating Scale for worst itch in the past 7 days, and lesion severity was determined by Eczema Area and Severity Index (EASI). The last recorded therapy, whether systemic (e.g. methotrexate, ciclosporin, mycophenolate) or advanced (e.g. biologics, Janus kinase inhibitor) was compared between subgroups. Patient proportions in each subgroup were MI-ML (42%), SI-ML (28%), SI-SL (17%) and MI-SL (13%). Patients with severe lesions (SI-SL/MI-SL) tend to be classified as having more severe disease overall by physicians, which is supported by these two subgroups having the highest frequency of progression to advanced therapy: 37% in SI-SL, 36% in MI-SL, 30% in SI-ML and 0% in MI-ML. Nevertheless, despite lesion severity (EASI) being statistically similar between the SI-ML and MI-ML groups, none of those in the MI-ML group went on to have advanced therapies, even though it was the largest group. The itch-dominant phenotype (SI-ML) is the largest cohort of patients with severe AD in this study, and these patients may need to progress to advanced therapy earlier to achieve better disease control. Itch assessment is not routinely conducted in UK clinics and is not included in the NICE guidelines. Future research is needed to expand and consolidate these findings.

BACKGROUND:Interleukin (IL)-17 inhibitors are effective in treating psoriatic disease, but paradoxical inflammatory reactions can occasionally occur. Palmoplantar pustular psoriasis (PPP) onset or flares have been rarely reported with anti-IL-17A but not dual IL-17A/F inhibition (bimekizumab). METHODS:Retrospective study: patients developing PPP while on anti-IL-17 were retrieved from hospital databases. RESULTS:Ten new PPP cases occurred during treatment with anti-IL-17: median age 46 years (range 33-59), females 40%. Six patients were obese, five smokers. Different IL-17 inhibitors were implicated, including secukinumab (n = 4), ixekizumab (n = 4), and for the first reported time bimekizumab (n = 2). PPP occurred after a median of 3 months (range 1-60) from anti-IL-17 initiation, earlier in those who did not respond in the primary disease domain (2 months, range 1-3) compared to responders (median 10 months, 1-60). Management of PPP included anti-IL-17 retention with topical agents, ciclosporin or colchicine, switching within class, or swapping to other mechanisms of action (IL-23, TNF, and JAK inhibition). Clinical benefit was reported with all approaches on available follow-up. CONCLUSIONS:PPP is rare during IL-17 inhibition but can occur under dual IL-17A/F inhibition. The underlying immunological mechanisms may involve neutrophil inflammation that independent from type-17 immune response.

Abstract Background/Aims Obesity impacts psoriatic disease (PsD) particularly regarding disease onset, disease severity and treatment non-response. The new weight-loss agents, such as Glucagon-Like Peptide-1 Receptor Agonists (GLP-1RA) have potential benefits for PsD disease activity and related co-morbidities but come with significant cost. We were therefore keen to explore rheumatologists and dermatologists’ opinions on the potential role of these drugs in the management of PsD. Methods We conducted an online survey of rheumatology and dermatology colleagues between the 7th April and 22nd of September 2025. Questions were developed through expert consensus and covered speciality, job role, region of practice, clinical setting, the impact of excess weight on disease and treatment response, and the monitoring and management of adiposity in PsD. Target health professionals included consultants, speciality doctors, registrars, research fellows, physiotherapists, and nurse specialists. The survey was disseminated ad hoc via professional and institutional mailing lists. Although originally meant for UK-based clinicians, the survey was later opened to international colleagues. Results were analysed with descriptive statistics. Results We received 190 responses, 150 from the UK (79%), with rheumatology contributing 131 (69%) and dermatology 59 (31%). Most respondents were consultants (68%) working in academic units/teaching hospitals (64%). Only 25% of respondents measured weight and BMI at every clinic visit, despite the majority believing that excess adiposity decreases treatment response to csDMARDs (73%) and ts/bDMARDs (75%), increases inflammatory drive and/or disease activity (87%), and is associated with cardiovascular/diabetic comorbidities (93%). Overall, 62% of respondents said that they consistently address excess adiposity in their patients, mainly through weight loss advice (92%) or weight management referral (47%). Barriers to addressing excess adiposity included time pressures, a lack of expertise and a lack of local services. Respondents were more favourable towards a hypocaloric diet over a GLP-1RA for the management of PsD in those living with overweight or obesity, including before PsA-onset in high-risk patients (35% vs 27%), before initiating systemic DMARD (52% vs 27%) or alongside the prescription of a systemic DMARD (46% vs 36%). Opinions around GLP-1-RA therapy were generally positive, with the caveat that further evidence of their efficacy and safety in PsA is required (28%). Only 1 respondent (<1%) felt GLP-1RA had no role in the management of PsD. Conclusion Clinicians treating PsD agree that excess adiposity promotes higher disease activity and cardiometabolic comorbidity, and lower treatment response, in alignment with the current literature. Interestingly, despite the current interest around GLP-1-RA agents, colleagues were relatively cautious, citing the need for further high-quality evidence for the safety and efficacy of these drugs in PsD. As such, high-quality randomised controlled trials are needed to assess the utility of these medications as an adjunctive treatment in the management of PsD. Disclosure J.C. Williams: None. P. Helliwell: None. D. McGonagle: None. J. Freeston: None. L. Ferguson: None. N. Gullick: None. S.R. Harrison: None. P. Laws: None. G. De Marco: None. J. Packham: None. J. Weddell: None. K. Shams: None. A. Tan: None. W. Tillett: None. S. Zhao: None. N. Sattar: None. S. Siebert: None. H. Marzo-Ortega: None.

Patients with hidradenitis suppurativa experience frequent pain which affects mood, quality of life, relationships and physical activity. Surveys and focus groups revealed that dermatologists rank pain management importance more highly than pain specialists and healthcare professionals in primary care but that they lack confidence in managing it. This study highlights the need for improved pain management education for dermatologists, multidisciplinary care pathways and better coordination between dermatology and primary care to support patients.

Chronic itch is the most burdensome symptom of atopic dermatitis (AD), yet its routine assessment and measurement remain inconsistent. This study aimed to characterise current practices for evaluating itch in AD among UK dermatologists and, through a narrative review, to summarise available itch assessment tools and inform practical recommendations for routine practice. This was a cross-sectional clinician survey and narrative literature review. A total of 394 dermatologists participated in the survey of itch and its assessment in AD during the 2024 British Association of Dermatologists Annual Meeting. Dermatologists reported itch as the most bothersome symptom in atopic dermatitis (78.68

Abstract Introduction and aims The skin is the essential first site of infection for all mosquito-borne viruses. Events occurring in the skin immediately after mosquito transmission critically shape viral replication and disease outcome. Environmental factors that modify cutaneous immunity therefore have the potential to alter host susceptibility to infection. Ultraviolet (UV) radiation is a common and clinically relevant skin stressor that induces inflammation and tissue remodelling, yet its impact on arbovirus infection is poorly understood. The aim of this study was to determine how prior UV exposure alters the cutaneous immune environment to influence arbovirus susceptibility, and to define the cellular mechanisms and UV wavelengths (UVA vs. UVB) responsible. Methods We used an immunocompetent mouse model of arbovirus infection incorporating transmission by Aedes aegypti mosquito bite. Mice were exposed to erythemal or nonerythemal doses of UV radiation prior to infection. Skin immune responses were assessed by flow cytometry, histology and gene expression analysis. Myeloid cell recruitment was manipulated using depletion approaches. Stromal fibroblast proliferation was assessed in vivo, and complementary in vitro infections were performed using primary mouse skin fibroblasts under proliferative or quiescent conditions. Ongoing studies directly compare UVA and UVB exposure. Results Prior UV exposure significantly enhanced arbovirus infection in the skin for several weeks. UV rapidly induced chemokine expression and leucocyte infiltration. By 1 week post-UV exposure, the virus targeted proliferating skin fibroblasts. Preliminary in vitro data indicate that replicating fibroblasts are more permissive to viral infection than nondividing cells. Conclusions UV-induced skin inflammation and tissue remodelling create defined windows of heightened susceptibility to mosquito-borne virus infection. These findings highlight the central role of the cutaneous immune environment in shaping early infection and identify UV exposure as a modifiable risk factor influencing arboviral disease.

Risankizumab is an anti-interleukin-23 monoclonal antibody approved to treat moderate-to-severe psoriasis in the UK. Risankizumab can be used in first-line (biologic-naive) or biologic-experienced patients who have not responded to or are unable to tolerate their current therapy. Data collected in BADBIR from 15 July 2019 to 30 July 2024 were used to assess patients’ responses to risankizumab using Psoriasis Area and Severity Index (PASI) and Dermatology Life Quality Index (DLQI) in biologic-naive and biologic-experienced cohorts. Data were analysed for patients who had a recorded baseline score at risankizumab initiation and at least one follow-up score within 2 years of initiation. At baseline, mean PASI scores were 13.1 (SD 8.72, n = 403) for the biologic-naive and 8.75 (SD 8.27, n = 679) for the biologic-experienced risankizumab cohorts. Mean PASI scores fell to 1.00 (SD 1.66, n = 126) in the biologic-naive cohort within 6 months and 1.41 (SD 3.52, n = 103) within 2 years. Mean PASI scores in the biologic-experienced cohort fell to 2.76 (SD 4.56, n = 279) within 6 months and 2.61 (SD 4.56, n = 188) within 2 years. Significantly more biologic-naive patients had achieved ≥ 90% and 100% improvement in Psoriasis Area and Severity Index (PASI 90 and PASI 100, respectively) than biologic-experienced patients within 2 years. In total, 74.6% of biologic-naive patients (n = 297/398) vs. 42.1% of biologic-experienced patients (n = 272/646) achieved PASI 90, P < 0.001; while 56.5% of biologic-naive patients (n = 225/398) vs. 30.8% of biologic-experienced patients (n = 199/646) achieved PASI 100, P < 0.001. At baseline, mean DLQI scores were 9.44 (SD 9.28, n = 419) for the biologic-naive and 8.71 (SD 8.02, n = 233) for the biologic-­experienced cohorts. The mean DLQI score reduction was greater in the biologic-naive cohort than in the biologic-­experienced cohort, decreasing to 2.63 (SD 5.19, n = 120) vs. 4.57 (SD 5.84, n = 78), respectively, within 6 months, P < 0.001. By 2 years, the mean DLQI fell to 1.89 (SD 2.97, n = 60) in biologic-naive and 3.43 (SD 5.81, n = 44) in biologic-experienced patients. The minimal clinically important difference for DLQI is ≥ 4-point reduction, which was reached within 6 months and maintained to 24 months in both cohorts. Limitations in the BADBIR registry meant data were only available for patients with scores documented during clinical visits. Additionally, there were no comparator data as only risankizumab data were available from BADBIR. In conclusion, sustained skin clearance was observed in both biologic-naive and biologic-experienced patients, with greater benefits seen in biologic-naive patients. Significantly more biologic-naive patients achieved complete skin clearance within 2 years compared with biologic-experienced patients (56.5% vs. 30.8%, P < 0.001). Real-world UK data confirm high levels of skin clearance and sustained response with risankizumab, consistently with clinical trial data.

The British Association of Dermatologists Biologics and Immunomodulators Register (BADBIR) is a prospective, observational cohort that records real-world psoriasis data in the UK and Ireland. Bimekizumab is a monoclonal immunoglobulin G1 antibody biologic that targets both interleukin-17A and interleukin-17F, and is approved for the treatment of both psoriasis and psoriatic arthritis in the UK. The aim of this study was to compare the patient characteristics of biologic-experienced and biologic-naive patients with chronic plaque psoriasis treated with bimekizumab. The BADBIR bimekizumab cohort included patients aged ≥ 18 years initiated on bimekizumab for chronic plaque psoriasis. The cohort was stratified into two subgroups: biologic-experienced and biologic-naive patients. Baseline patient characteristics were extracted, including biologic status, number of prior biologics, age of psoriasis onset, Psoriasis Area and Severity Index (PASI) and Dermatology Life Quality Index (DLQI) scores, psoriatic arthritis, comorbidities, site involvement, sex and disease duration. Overall, 326 patients were enrolled in the bimekizumab cohort (data lock: 1 August 2024). More patients were biologic experienced than biologic naive (Table). In the biologic-experienced subgroup, 70% (n = 182) of patients received two or more prior biologics. The average age of psoriasis onset, and PASI and DLQI scores were lower among patients with available data in the biologic-experienced subgroup than in the biologic-naive subgroup. Biologic-experienced patients had a higher rate of psoriatic arthritis and more comorbidities than those who were biologic naive. Both biologic-experienced and biologic-naive patients had high rates of high-impact site involvement, with scalp and nail psoriasis present. In conclusion, biologic-experienced patients receiving bimekizumab had a more complex patient profile, with multiple previous biologics and more comorbidities than those who were biologic naive. For those patients receiving bimekizumab who were biologic naive, most had greater disease severity and higher patient-reported quality-of-life scores than biologic-experienced patients. Further analysis might clarify whether these differences impact patient outcomes following bimekizumab treatment.TablePatient characteristics of biologic-experienced and biologic-naive patients with chronic plaque psoriasis treated with bimekizumab in BADBIRPatient characteristicsBiologic experiencedBiologic naiveP-valueNumber of patients, n (%)260 (79.8)66 (20.2)Age (years)44.0 (12.3)49.5 (14.4)< 0.001Male, n (%)156 (60.0)43 (65)0.44Disease duration (years)20.5 (12.6)21.5 (15.6)0.47Number of comorbidities2.0 (1.7)1.8 (1.7)< 0.001Age of psoriasis onset (years)23.5 (13.9)28.0 (16.1)0.10PASI score12.2 (9.1); n = 19616.9 (6.5); n = 630.001DLQI total score13.4 (8.0); n = 8219.8 (7.1); n = 360.005Psoriatic arthritis, n (%)89 (34.2)15 (23)0.07High-impact site involvement Scalp, n (%)189 (72.7)43 (65)0.23 Nail, n (%)130 (50.0)38 (58)0.27The results are the mean (SD), and from all patients in the subgroup unless indicated otherwise. DLQI, Dermatology Life Quality Index; PASI, Psoriasis Area and Severity Index.

BACKGROUND:Pivotal clinical trials have assessed the efficacy and safety of fixed-dose upadacitinib 15 mg (UPA15) and 30 mg (UPA30) once daily in atopic dermatitis (AD). OBJECTIVES:To assess the efficacy and safety of dose escalation to UPA30 and dose reduction to UPA15 based on a clinical response [90% reduction in Eczema Area and Severity Index (EASI 90)] after 12 weeks of treatment in adults with moderate-to-severe AD enrolled in a randomized blinded treat-to-target multicentre phase IIIb/IV study. METHODS:A total of 461 patients were randomized in a 1 : 1 ratio to receive oral doses of UPA15 (n = 229) or UPA30 (n = 232) once daily during the 12-week double-blinded period. At week 12, patients on UPA15 not achieving EASI 90 were dose escalated to UPA30 (UPA15/30); patients achieving ≥ EASI 90 continued on UPA15 (UPA15/15). Patients on UPA30 not achieving EASI 90 at week 12 continued on UPA30 (UPA30/30); patients achieving ≥ EASI 90 received a reduced dose of UPA15 (UPA30/15) for 12 additional weeks. The primary efficacy endpoint was EASI 90 achievement at week 24. Results were reported descriptively as observed. Safety outcomes were assessed. RESULTS:At week 24, of patients who received dose escalation (UPA15/30), 48.1% [n = 64/133; 95% confidence interval (CI) 39.6-56.6] achieved EASI 90; of patients who received a dose reduction (UPA30/15), 68.5% (n = 89/130; 95% CI 60.5-76.4) maintained EASI 90. Of patients who continued on their initial dose, 29.3% (n = 24/82; 95% CI 19.4-39.1) on UPA30/30 achieved EASI 90 and 74.6% (n = 53/71; 95% CI 64.5-84.8) on UPA15/15 maintained EASI 90. At week 24, 32.5% (n = 27/83; 95% CI 22.5-42.6) and 38.0% (n = 38/100; 95% CI 28.5-47.5) of patients on UPA15/30 and UPA30/15, respectively, achieved a worst pruritus numerical rating scale score of 0 or 1 (WP-NRS 0/1), and 20.7% (n = 17/82; 95% CI 12.0-29.5) and 35.0% (n = 35/100; 95% CI 25.7-44.3), respectively, achieved combined EASI 90 and WP-NRS 0/1. At week 24, treatment emergent adverse events were reported in 43.1% (n = 31/72; UPA15/15), 54.2% (n = 78/144; UPA15/30), 61.5% (n = 56/91; UPA30/30) and 48.9% (n = 65/133; UPA30/15) of patients. No malignancies, adjudicated venous thromboembolic events or deaths were reported. CONCLUSIONS:Treatment of moderate-to-severe AD with UPA15 or UPA30, with dose escalation or dose reduction based on achievement of the optimal treatment target of EASI 90 at week 12, demonstrated that both approaches support the achievement and maintenance of EASI 90 at week 24. Overall safety findings were consistent with the known UPA safety profile, with no new safety signals identified.

GP2015 (Erelzi; Sandoz) is an etanercept biosimilar indicated for several inflammatory disorders, including moderate-to-severe plaque psoriasis. The British Association of Dermatologists Biologics and Immunomodulators Register (BADBIR) is a prospective observational cohort study designed to monitor the long-term safety of biologic therapies for psoriasis. The purpose of this study, funded by Sandoz, was to describe baseline characteristics and safety outcomes in patients enrolled in BADBIR and treated with GP2015 or conventional therapy. Adult (≥ 18 years) and paediatric (< 18 years) patients with plaque psoriasis were recruited between 5 October 2017 and 31 July 2022 from 165 sites across the UK and Ireland. The GP2015 cohort included patients who started GP2015 within ≤ 6 months. The conventional therapy cohort included biologic-naive patients who started conventional systemic therapy within ≤ 6 months. Adverse event (AE) rates per 1000 patient-years were calculated for each cohort. Time to first event was compared using Cox proportional hazard models, when at least one event was observed in each cohort, with ≥ 10 total events. Models were adjusted using deciles of a propensity score calculated using baseline variables. Missing data were replaced using multiple imputation. Overall, 42 and 6013 patients were included in the GP2015 and conventional therapy cohorts, respectively. At baseline, the mean disease duration was longer (25.3 vs. 18.2 years) and the Psoriasis Area and Severity Index score was lower (12.8 vs. 15.2) in the GP2015 vs. the conventional therapy cohort, respectively. In the GP2015 cohort, two AEs occurred (one cardiac serious AE and one malignant event). In the conventional therapy cohort, common AEs included serious infections (n = 635) and malignant events (n = 346). There were no cases of tuberculosis in either cohort. Among patients with psoriasis treated with GP2015, AE rates were low. However, patient numbers at this stage are limited and greater numbers are required to further assess safety outcomes.

Arbovirus transmission by sand flies is a growing public health concern, yet the early skin events shaping infection outcomes remain undefined. We establish a mouse model of Toscana virus (TOSV) infection that incorporates sand fly salivary factors to mimic natural transmission. Saliva from two distinct sand fly genera significantly enhanced infection and promoted neurological signs and joint inflammation, recapitulating key features of human TOSV disease. In the skin, dermal macrophages and fibroblasts were the main infected cell types, but only fibroblasts generated infectious virus. Saliva reprogrammed fibroblasts into a wound-healing state permissive to viral replication, driving local viral amplification, systemic spread, and thereby clinical disease. These findings identify skin fibroblasts as central determinants of host susceptibility and reveal that sand fly saliva actively remodels the skin to exacerbate viral pathogenesis. This work redefines the skin’s role in sand fly-transmitted infection and highlights new targets for therapeutic and vaccine development.

We describe comorbidities and cardiovascular diseases (CVD) risk in patients with psoriasis prescribed apremilast in UK clinical practice. Such real-world data are currently sparse. This observational, retrospective analysis of British Association of Dermatologists Biologic and Immunomodulators Register (BADBIR) included adults with plaque psoriasis first prescribed apremilast between October 2015 and March 2021. We evaluated patient comorbidities, 10-year CVD risk (Framingham risk score), time from psoriasis diagnosis, prior therapy, psoriasis severity and patient-reported quality of life (QoL) at first apremilast prescription or registry enrolment. Patient characteristics were also assessed by CVD risk and Fitzpatrick skin type. Of 265 eligible patients, 47.5