Hyperactivation of the JAK2/STAT5 Signaling Pathway and Evaluation of Baricitinib Treatment Among Patients With Eosinophilic Cellulitis.

Importance: The pathogenesis of eosinophilic cellulitis (EC) is poorly understood, limiting available treatment options. The current treatment paradigm focuses on delayed type 2 hypersensitivity reaction to various triggers. Objective: To gain further insight into the nature of EC inflammation and into the cellular signal transduction pathways that are activated in the context of EC. Design, Setting, and Participants: This case series was conducted in Lyon, France, from January 2018 to December 2021. Analysis of archival skin biopsy samples from patients with EC and from healthy control participants was performed using histology, Janus kinase (JAK)-signal transducer and activator of transcription (STAT) immunohistochemistry, and gene profiling. Data analysis was conducted between January 2020 and January 2022. Main Outcomes and Measures: Pruritus (visual analog score), percentage of body surface area with lesional skin, and RNA transcripts of inflammatory biomarkers from the skin (threshold cycle) were assessed in 1 index patient with refractory EC who received oral JAK1/JAK2 inhibitor baricitinib (4 mg/d). Results: This study included samples from 14 patients with EC (7 men and 7 women) and 8 healthy control participants (4 men and 4 women). The mean (SD) age of patients was 52 (20) years. Marked type 2 inflammation (chemokines CCL17, CCL18, and CCL26 and interleukin 13) with preferential activation of the JAK1/JAK2-STAT5 pathways in EC lesions was observed. In the 1 index patient with refractory EC, complete clinical remission of skin lesions was observed after 1 month of treatment with baricitinib. Conclusions and Relevance: These findings suggest that EC is a type 2 inflammatory disease with preferential activation of the JAK1/JAK2-STAT5 pathways. In addition, these results suggest the potential of treatment approaches targeting JAK1/JAK2 for patients with EC.

Treatment of dissecting cellulitis of the scalp with tumour necrosis factor inhibitors: a retrospective multicentre study.

Although retinoids are considered as the most effective treatment, management of dissecting cellulitis of the scalp (DCS) is often challenging. A multicentre retrospective study was conducted to evaluate the efficacy of anti-tumour necrosis factor (TNF) agents in treating DCS after failure of other conventional treatments. Twenty-six patients were included. After a mean treatment duration of 19 months (SD 21), the median Physician's Global Assessment score decreased from 3 to 1. The median number of inflammatory nodules and abscesses decreased from 7 to 0.5 and from 1 to 0, respectively. The median Dermatology Life Quality Index and numerical rating scale score for pain severity decreased from 10 to 8 and 6 to 1, respectively. The median treatment satisfaction was 7 out of 10 on the Patient Satisfaction Index. This study confirms the efficacy of anti-TNF agents in treating patients with DCS that is resistant to conventional therapies.

Distal phalangeal bone erosions observed by HR-pQCT in patients with psoriatic onycholysis.

OBJECTIVES: PsA prevalence among skin psoriasis is ∼30%. Nail psoriasis, especially onycholysis, is present in >70% of PsA and the risk of developing PsA is more than doubled in patients with nail involvement. We hypothesized that onycholysis may be associated with early bone erosions of the DIP joint without harbouring PsA symptoms. METHODS: We compared tendon thickness, assessed by US, and bone erosions, assessed by high-resolution peripheral quantitative CT, of the DIP joint in patients with psoriatic onycholysis without PsA (ONY) with those in patients with cutaneous psoriasis only (PSO). We used patients with PsA as reference (PsA group), and healthy age-matched controls (CTRL). Differences between groups were assessed by analysis of variance tests followed by post hoc analysis using the Scheffe method. RESULTS: Mean (s.e.m.) age of the 87 participants (61% males) was 45.2 (1.3) years. The mean extensor tendon thickness was significantly larger in ONY than in PSO patients. In the PsA group, 68% of patients exhibited erosions of three different shapes: V-, Omega- and U-shape. Association with erosions was greater in the ONY group than in the PSO group (frequency: 57 vs 14%; P < 0.001; mean number of erosions: 1.10 (0.35) vs 0.03 (0.03); P < 0.001). CONCLUSION: Onycholysis was associated with significant enthesopathy and bone erosions in our cohort. These data support the pathogenic role of enthesopathy in PsA. Onycholysis may be considered as a surrogate marker of severity in psoriasis. TRIAL REGISTRATION: ClinicalTrails.gov, https://clinicaltrials.gov, NCT02813720.

Long-Term Infliximab Treatment in Psoriasis Patients: A National Multicentre Retrospective Study.

BACKGROUND: Although infliximab (IFX) has been available since 2005, there are very little data on the long-term drug survival of infliximab in real-life. OBJECTIVE: Our aim was to identify and describe psoriasis patients treated with IFX for longer than 6 years. METHODS: Psoriasis patients treated with IFX for longer than 6 years were retrospectively included. Demographic and clinical data were collected in May 2018. RESULTS: Between January 2005 and December 2012, 43 patients were maintained on IFX for 6 years or longer. IFX was introduced as a 4.5 line of systemic therapy. The mean duration of IFX treatment was 8.5 years (6-12). In May 2018, 30 patients (70%) were still maintained on IFX at 4-6 mg/kg every 8-10 weeks with an efficiency of about 100%. IFX was stopped in 13 patients (30%) mainly for loss of efficacy in 6 patients (46%). Three patients developed solid cancer including bladder cancer, lung cancer, and prostate cancer. Limitation. Retrospective study. CONCLUSION: We report the efficacy and safety of IFX maintained for up to 12 years in psoriasis patients. The long-term use of IFX was associated with a high BMI confirming the critical role of weight-based dosing for this drug.

Clinical characteristics of pediatric hidradenitis suppurativa: a cross-sectional multicenter study of 140 patients.

Hidradenitis suppurativa (HS) rarely affects pediatric patients. The literature on pediatric HS patients is scarce. This is a cross-sectional study based on case note review or interviews and clinical examination of 140 pediatric patients undergoing secondary or tertiary level care. Patients were predominantly female (75.5%, n = 105) with a median age of 16. 39% reported 1st-degree relative with HS. Median BMI percentile was 88, and 11% were smokers (n = 15). Median modified Sartorius score was 8.5. Notable comorbidities found were acne (32.8%, n = 45), hirsutism (19.3%, n = 27), and pilonidal cysts (16.4%, n = 23). Resorcinol (n = 27) and clindamycin (n = 25) were the most frequently used topical treatments. Patients were treated with tetracycline (n = 32), or oral clindamycin and rifampicin in combination (n = 29). Surgical excision was performed in 18 patients, deroofing in five and incision in seven patients. Obesity seemed to be prominent in the pediatric population and correlated to parent BMI, suggesting a potential for preventive measures for the family. Disease management appeared to be similar to that of adult HS, bearing in mind that the younger the patient, the milder the disease in majority of cases.

Management of psoriatic arthritis among cutaneous psoriasis patients: from pathogenesis to therapy.

Psoriatic arthritis (PsA) is an inflammatory rheumatism belonging to spondyloarthritis family and which occurs in about 30% of patients with psoriasis. The pathogenesis entails a genetic predisposition, environmental and immunologic factors. Most of the time, cutaneous lesions precede apparition of articular manifestations and dermatologists who treat psoriatic patients have to regularly screen for early PsA, especially in patients with risk factors (notably nail psoriasis). Early detection greatly increases the chances for successful treatment and can prevent slow joint destruction. EULAR and GRAPPA have recently published PsA treatment recommendations. Pharmacological therapies for PsA begin with non-steroidal anti-inflammatory drugs, then conventional synthetic as methotrexate, and lastly biological disease-modifying anti-rheumatic drugs. There are significant metabolic comorbidities and increased cardiovascular morbidity in patients with PsA. This aspect must be taken into account in PsA management by pharmaceutical and non-pharmaceutical approach (including educational programs). Close collaboration between dermatologists, rheumatologists and primary care clinicians is recommended to provide optimum care and to prevent the occurrence of structural damages or quality of life alteration.

Hidradenitis suppurativa (HS): An unrecognized paradoxical effect of biologic agents (BA) used in chronic inflammatory diseases.

BACKGROUND: Paradoxical hidradenitis suppurativa (HS) induced by biologic agents (BA) is scarcely reported. OBJECTIVE: We sought to describe the clinical characteristics and outcome of patients developing paradoxical HS under BA. METHODS: This was a multicenter nationwide retrospective study asking physicians to report all cases of HS, confirmed by a dermatologist, occurring during treatment of an inflammatory disease by a BA. RESULTS: We included 25 patients (15 inflammatory rheumatism, 9 Crohn's disease, 1 psoriasis) treated by 5 BA (adalimumab = 12, infliximab = 6, etanercept = 4, rituximab = 2, tocilizumab = 1). Median duration of BA exposure before HS onset was 12 (range 1-120) months. Patients were mostly Hurley stage I (n = 13) or II (n = 11). Simultaneously to HS or within 1 year, 11 patients developed additional inflammatory diseases, including paradoxical reactions (psoriasis = 9, Crohn's disease = 3, alopecia areata = 1, erythema elevatum diutinum = 1). Complete improvement of HS was more frequently obtained after BA discontinuation or switch (n = 6/10, 60%) rather than maintenance (n = 1/14, 7%). Reintroducing the same BA resulted in HS relapse in 3 of 3 patients. LIMITATIONS: Retrospective nature and lack of complete follow-up for some patients are limitations. CONCLUSION: HS is a rare paradoxical adverse effect of BA, but fortuitous association cannot be excluded in some cases. We observed a trend toward better outcome when the BA was discontinued or switched.

Application of C4d Immunohistochemistry on Routinely Processed Tissue Sections for the Diagnosis of Autoimmune Bullous Dermatoses.

The diagnosis of autoimmune bullous dermatoses relies greatly on direct immunofluorescence (DIF) examination performed on frozen tissue sections, showing deposits of immunoglobulins and/or C3 on specific cutaneous structures. However, frozen material is not always available for DIF; therefore, alternative techniques are needed in the diagnostic procedure. We therefore tested the usefulness of C4d immunohistochemistry on formalin-fixed, paraffin-embedded tissue sections for the diagnosis of bullous pemphigoid (BP) and pemphigus (P). A retrospective immunohistochemical study was performed on biopsies of BP (n: 29) and P (n: 22, including 19 Pemphigus vulgaris and 3 paraneoplastic), submitted for routine histological examination and compared with DIF on the corresponding frozen sections. Twenty-five BP biopsies (86.2%) showed C4d deposits seen as a linear labeling along the dermal-epidermal junction and on the membrane of basal keratinocytes. Seventeen P biopsies (77.2%) showed C4d deposits in a classical "intercellular" pattern, predominating on the lower epidermal layers. The sensitivity, specificity, positive predictive value, and negative predictive value reached 86%, 98%, 96%, and 92% in BP, respectively and 77%, 98%, 94%, and 92% in P, respectively. Furthermore, in the cases where serological tests were available, the sensitivity of C4d detection was higher than that of enzyme-linked immunosorbent assay/indirect immunofluorescence in both BP (87% vs. 67%) and P (82% vs. 54.5%). We conclude that DIF on frozen sections still remains the gold standard for the immunopathological diagnosis of BP and P; however, in the absence of frozen material, C4d immunohistochemistry performed on routinely processed biopsy material can be of considerable help in confirming the diagnosis.

Prevalence of undiagnosed psoriatic arthritis among psoriasis patients: Systematic review and meta-analysis.

BACKGROUND: Skin psoriasis precedes the onset of psoriatic arthritis (PsA) in 84% of patients with psoriasis. Dermatologists have an important role to screen psoriasis patients for PsA. The efficiency of PsA screening remains unknown. OBJECTIVE: We sought to determine the point prevalence of undiagnosed PsA in patients with psoriasis using a systematic search of the literature and meta-analysis. METHODS: PubMed, Cochrane, and Embase database searches yielded 394 studies for review. No study aimed to determine the prevalence of undiagnosed PsA in patients with psoriasis. We assumed that the prevalence of newly diagnosed PsA in patients with psoriasis at the time they seek medical care could be a sound estimate of this value. Seven epidemiological studies and 5 studies on PsA screening questionnaires allowed us to clearly identify patients with newly diagnosed PsA and were selected for review. RESULTS: The prevalence of undiagnosed PsA was 15.5% when all studies were considered and 10.1% when only epidemiological studies were considered. LIMITATIONS: Data were obtained from studies not designed to address the question at hand. Heterogeneity was high (I(2) = 96.86%), and therefore a random effects model was used. CONCLUSION: The high prevalence of undiagnosed PsA in patients with psoriasis adds to the recommendation that dermatologists need to screen all patients with psoriasis for PsA.