Epidemiology and clinical characteristics of biopsy-confirmed adult-onset IgA vasculitis in southern Sweden.

OBJECTIVE: Immunoglobulin A vasculitis (IgAV) is the most prevalent primary childhood vasculitis in Sweden, but is considerably rarer in adults. This study aims to describe the epidemiology, clinical characteristics and renal outcome of adult-onset IgAV in Skåne, Sweden. METHODS: The study area consisted of Skåne, the southernmost region of Sweden, with a population ≥18 years of 990 464 on 31 December 2010. Adult patients assigned the International Classification of Diseases-10 code for IgAV (D69.0) from 2000 through 2019 were retrospectively identified in a population-based database. Medical records were reviewed to validate the diagnosis of IgAV and extract data. Only patients with clinical manifestations of IgAV and biopsy-confirmed disease were included. The annual incidence and point prevalence of biopsy-confirmed IgAV were estimated. RESULTS: Fifty-nine patients (19 women) were classified as having adult-onset IgAV. The incidence was 3 per 1 000 000 and was higher among men than women (4 vs 2/1 000 000, p=0.004). Ninety-seven per cent of patients presented with non-thrombocytopenic purpura, 78% with renal involvement, 59% with arthritis/arthralgia and 39% with gastrointestinal symptoms. Fifteen per cent developed chronic kidney disease stage ≥G3 a and one patient progressed to end-stage kidney disease during follow-up. CONCLUSION: Adult-onset IgAV is rare in southern Sweden with the incidence higher in men than in women. IgAV frequently affects the kidneys and leads to chronic kidney disease in adults, although the long-term renal outcome appears favourable compared with other small-vessel vasculitides affecting the kidneys.

Pregnancy outcome in patients with a medical history of immunoglobulin A vasculitis: a case-control study.

OBJECTIVE: Data on obstetric outcomes in patients with a history of immunoglobulin A vasculitis (IgA-V) are lacking. The aim of this study was to assess maternal, neonatal, and vasculitis outcomes during pregnancy. METHOD: We conducted a French retrospective case-control study. Pregnancies of patients with a history of IgA-V (cases) were retrospectively studied and compared to pregnancies in women who developed IgA-V after their pregnancies and to pregnancies in healthy women (controls). RESULTS: Twenty-six pregnancies in patients with a history of IgA-V were included and compared to 15 pregnancies in women who later developed IgA-V and 52 pregnancies in healthy women. Both gestational hypertension and pre-eclampsia were more frequent in the case group than in the other groups (23% vs 0% vs 0%, p < 0.01; 12% vs 7% vs 0%, p = 0.04). Hypertensive disorder of pregnancy occurred more frequently in patients with pre-existing kidney disease (78% vs 12%, p < 0.01). Caesarean section was more often performed in the case group than in the other groups (27% vs 0% vs 10%, p = 0.04). No foetal loss or maternal deaths occurred. There were no differences in delivery term or birth weight. No vasculitis flares were observed during pregnancy. CONCLUSION: Women with a history of IgA-V appear to be at higher risk for gestational hypertension and pre-eclampsia, especially in cases with renal involvement; however, both mother and newborn outcomes appear to be favourable.

Risk of Hypertensive Disorders and Preterm Birth in Pregnant Women With Systemic Vasculitides: A Nationwide Population-Based Cohort Study.

OBJECTIVE: Even though systemic vasculitides (SVs) affect primarily patients over 50 years of age, they can occur among women of childbearing age. Preterm birth (PTB) and hypertensive disorders are frequent complications of pregnancy in SVs. This study aims to evaluate the risk of hypertensive disorders and PTB among pregnant women with SVs, and to identify associated risk factors. METHOD: Using the French health insurance data warehouse, we conducted a nationwide cohort study including all pregnancies between 2013 and 2018 in women with SVs. Theses pregnancies were matched to pregnancies among women without SVs. We estimated risk of hypertensive disorders and PTB risk during pregnancy among women with SVs and investigated associated risk factors using a nested case-control design. RESULTS: Among 3,155,723 pregnancies, we identified 646 pregnancies in women with SVs, matched to 3,230 controls. SVs were significantly associated with hypertensive disorders (odds ratio [OR] 1.7, 95% confidence interval [95% CI] 1.3-2.2) and PTB (OR 1.8, 95% CI 1.4-2.3). Chronic renal failure before pregnancy, history of or treated arterial hypertension, the occurrence of vasculitides flare during pregnancy, and the subgroup of SVs were independently associated with the occurrence of hypertensive disorders. Maternal age at delivery, chronic renal failure before conception, and the occurrence of vasculitides flare during pregnancy were independently associated with the occurrence of PTB. CONCLUSION: About one of seven pregnancies in women with SVs is associated with hypertensive disorders or preterm birth. The occurrence of vasculitides flare was associated with these complications. Our findings support the importance of prepregnancy counseling to ensure disease stability.

Medium-vessel and large-vessel vasculitis in children.

PURPOSE OF REVIEW: This article serves as an up-to-date examination of the latest findings in the field of paediatric large-vessel and medium-vessel vasculitis. RECENT FINDINGS: Over the last 2 years and in the wake of SARS-CoV2 pandemic, a multitude of studies have increased our insight into these conditions. Although large-vessel and medium-vessel vasculitis are uncommon amongst children, they are a complex and multisystem with a constantly evolving landscape. Increasing numbers of reports from low-income and middle-income countries are shaping our understanding of the epidemiology of vasculitis in children. The influence of infectious disease and the microbiome are of particular interest in unravelling pathogenetic aspects. Improved understanding of the genetics and immunology offer opportunities for better diagnostic options and biomarkers of disease as well as targeted therapies. SUMMARY: In this review, we address recent findings in epidemiology, pathophysiology, clinical findings, bio-markers, imaging and treatment that have the potential to offer better management solutions for these uncommon conditions.

Systemic vasculitis: one year in review 2023.

Systemic vasculitides are heterogeneous disabling diseases characterised by chronic inflammation of the blood vessels potentially leading to tissue destruction and organ failure. The recent COVID-19 pandemic has had a significant impact on the epidemiology and management of patients with systemic vasculitis. In parallel, new insights have been provided on systemic vasculitis pathogenetic mechanisms, possible new therapeutic targets, and newer glucocorticoid-sparing treatments with better safety profiles. As in the previous annual reviews of this series, in this review we will provide a critical digest of the most recent literature regarding pathophysiology, clinical manifestations, diagnostic tools and treatment options in small- and large-vessel vasculitis focusing on precision medicine in vasculitis.

Eosinophilic/T-cell Chorionic Vasculitis: Its Incidence Is Increasing but It Does Not Appear to Recur in Subsequent Pregnancies.

INTRODUCTION: Eosinophilic/T-cell chorionic vasculitis (E/TCV), an incidental finding primarily in third trimester placentas, is characterized by eosinophils and CD3+ T lymphocytes infiltrating at least 1 chorionic and/or stem villous vessels. Its etiology and clinical significance are unclear. METHODS: Placental pathology reports issued by 8 pediatric-perinatal pathologists at Alberta Children's Hospital were retrieved from the lab information system (2010-2022), and candidate reports were identified using a Perl script searching for "eosinophil." Candidate diagnoses of E/TCV were validated by pathologist review. RESULTS: 38,058 placenta reports from 34,643 patients were reviewed; 328 cases of E/TCV were identified, for an overall incidence of 0.86%. Incidence increased 23% per year, from 0.11% in 2010 to 1.5% in 2021 (P < .01). This temporal change was observed for all pathologists; the incidence of identified multifocality also increased over time (P < .01). Umbilical vascular involvement was exceedingly rare. No variation in incidence was attributable to season. We received more than 1 placenta from 46 mothers with an E/TCV placental diagnosis; examination of >1 placenta did not reveal any mother with >1 E/TCV diagnosis. CONCLUSIONS: The incidence of E/TCV increased steadily over a ~12-year period and no recurrent cases were observed.

The Characteristics of Patients With COVID-19-Associated Pediatric Vasculitis: An International, Multicenter Study.

OBJECTIVE: COVID-19-associated pediatric vasculitis, other than Kawasaki disease (KD)-like vasculitis in multisystem inflammatory syndrome in children (MIS-C), is very rare. This study sought to analyze the characteristics, treatment, and outcomes in patients with COVID-19-associated pediatric vasculitis (excluding KD-like vasculitis in MIS-C). METHODS: The inclusion criteria were as follows: 1) age <18 years at vasculitis onset; 2) evidence of vasculitis; 3) evidence of SARS-CoV-2 exposure; and 4) ≤3 months between SARS-CoV-2 exposure and vasculitis onset. Patients with MIS-C were excluded. The features of the subset of patients in our cohort who had COVID-19-associated pediatric IgA vasculitis/Henoch Schönlein purpura (IgAV/HSP) were compared against a pre-pandemic cohort of pediatric IgAV/HSP patients. RESULTS: Forty-one patients (median age 8.3 years; male to female ratio 1.3) were included from 14 centers and 6 countries. The most frequent vasculitis subtype was IgAV/HSP (n = 30). The median duration between SARS-CoV-2 exposure and vasculitis onset was 13 days. Involvement of the skin (92.7%) and of the gastrointestinal system (61%) were the most common manifestations of vasculitis. Most patients (68.3%) received glucocorticoids, and 14.6% also received additional immunosuppressive drugs. Remission was achieved in all patients. All of the patients with IgAV/HSP in our cohort had skin manifestations, while 18 (60%) had gastrointestinal involvement and 13 (43.3%) had renal involvement. When we compared the features of this subset of 30 patients to those of a pre-pandemic pediatric IgAV/HSP cohort (n = 159), the clinical characteristics of fever and renal involvement were more common in our COVID-19-associated pediatric IgAV/HSP cohort (fever, 30% versus 5%, respectively [P < 0.001]; renal involvement, 43.3% versus 17.6%, respectively [P = 0.002]). Recovery without treatment and complete recovery were each less frequent among our COVID-19-associated pediatric IgAV/HSP patients compared to the pre-pandemic pediatric IgAV/HSP cohort (recovery without treatment, 10% versus 39%, respectively [P = 0.002]; complete recovery, 86.7% versus 99.4%, respectively [P = 0.002]). CONCLUSION: This is the largest cohort of children with COVID-19-associated vasculitis (excluding MIS-C) studied to date. Our findings suggest that children with COVID-19-associated IgAV/HSP experience a more severe disease course compared to pediatric IgAV/HSP patients before the pandemic.

Does COVID-19 increase the incidence of spontaneous rectus sheath hematoma?

BACKGROUND: The COVID-19 pandemic started to affect Turkey in March 2020. In this study, we retrospectively investigated spontaneous rectus sheath hematoma (S-RSH) in patients with COVID-19 presenting with acute abdominal pain during the ongoing pandemic. METHODS: The demographic characteristics, laboratory findings, length of hospital stay, and treatment processes of COVID-19 cases with S-RSH detected between March and December 2020 were recorded. The rectus sheath hematoma diagnosis of the patients was made using abdominal computed tomography, and the patients were followed up. Low-molecular-weight heparin treatment, which was initiated upon admission, was continued during the follow-up. RESULTS: S-RSH was detected in 13 out of 220 patients with COVID-19 who were referred to general surgery for consultation due to acute abdominal pain. The mean age of these patients was 78±13 years, and the female-to-male ratio was 1.6. Mechanical ven-tilation support was applied to three patients, all of whom were followed up in the intensive care unit. Two patients died for reasons independent of rectus sheath hematoma during their treatment. Among the laboratory findings, the activated partial thromboplastin time (aPTT) values did not deviate from the normal range. While there was no correlation between the international normalized ratio (INR) and aPTT (p>0.01), a significant correlation was found between INR and interleukin-6 (IL-6) (p<0.002). None of the patients required surgical or endovascular interventional radiology procedures. CONCLUSION: In the literature, the incidence of S-RSH in patients presenting with acute abdominal pain is 1.8%. However, in our series, this rate was approximately 3 times higher. Our patients' normal INR and aPTT values suggest that coagulopathy was mostly secondary to endothelial damage. In addition, the significantly higher IL-6 values (p<0.002) indicate the development of vasculitis along with the acute inflammatory process. S-RSH can be more commonly explained the high severity of vasculitis and endothelial damage due to viral infection.

Case-Control Study on Exercise-Induced Vasculitis in Hikers.

The aim of this study was to identify clinical factors associated with exercise-induced vasculitis (EIV). This study included EIV cases and controls matched for age. Cases included were all members of a hiking club and participated in extended hiking trips. Exercise-induced vasculitis was diagnosed based on clinical signs occurring only after prolonged walks. Chronic venous disease was defined using the Clinical Etiological Anatomical Pathophysiologic classification. This study included 162 hikers: 32 EIV cases and 130 matched controls. Mean age at EIV diagnosis was 47.1 years and 24 (75.0%) of EIV cases were women. Chronic venous disease was present in 19 (57.6%) of EIV cases vs 39 (30.0%) in controls (P = .001); those with EIV had significantly more saphenous vein insufficiency and C3 venous insufficiency than controls, 85.0 vs 52.6% and 8 (25.0%) vs 13 (10.0%) (P = .02), respectively. For EIV cases, mean walking distance per hike was significantly higher than for controls (P = .002). Exercise-induced vasculitis symptoms were typical with rash and/or purpura on the leg in warm conditions. Lesions spontaneously disappear in <10 days. In this study, EIV cases had more chronic venous disease and longer mean walking distances than controls.

Persistence and Severity of Cutaneous Manifestations in IgA Vasculitis Is Associated with Development of IgA Vasculitis Nephritis in Children.

BACKGROUND/OBJECTIVE: The purpose of this study was to evaluate the prevalence and severity of skin involvement in children with IgA vasculitis (IgAV) and its relationship with clinical and biochemical parameters and the risk of developing IgA vasculitis nephritis (IgAVN), the only cause of long-term morbidity and the main prognostic factor in IgAV patients. METHODS: This national multicenter retrospective study included 611 patients under the age of 18 years with IgAV referred to five Croatian tertiary hospitals between 2009 and 2019. Patient data were collected from a database with systematic analysis of IgAV patients in the Croatian population. RESULTS: Among the 611 children, 205 (33.55%) had purpura on the lower extremities, in 207 (33.88%) the rash extended on the trunk, in 149 (24.39%) it extended to the upper extremities, in 32 (5.24%) the rash was generalized, while 15 (2.47%) had the most severe skin symptoms: bullae, ulcerations, and necroses. IgAVN developed in 130 (21.28%) and persistent IgAVN (present for >3 months) in 48 (7.86%) children. Multivariate logistic regression found that presence of ulcerations and necroses (OR 3.20 [95% CI 1.03-9.91]), persistent purpura (OR 2.89 [95% CI 1.71-4.88]), and higher age (OR 1.16 [95% CI 1.09-1.23]) were significant predictors of IgAVN, whereas persistent purpura (OR 20.11 [95% CI 1.09-372.52]), male sex (OR 3.32 [95% CI 1.13-9.80]), and higher age (OR 1.15 [95% CI 1.00-1.30]) were predictors of persistent IgAVN. Among the laboratory parameters, higher serum urea (OR 1.43 [95% CI 1.03-2.00]) and reduction in activated partial thromboplastin time (OR 0.83 [95% CI 0.74-0.93]) were shown to have a significant impact on increasing the risk of persistent IgAVN. CONCLUSION: With increasing severity and duration of cutaneous manifestations in IgAV, the risk of developing IgAVN increases, making the prognosis worse, with a greater likelihood to need more aggressive treatment.

Global epidemiology of vasculitis.

The many forms of vasculitis are characterized by inflammation of blood vessels, leading to potentially long-term sequelae including vision loss, aneurysm formation and kidney failure. Accurate estimation of the incidence and prevalence has been hampered by the absence of reliable diagnostic criteria and the rarity of these conditions; however, much progress has been made over the past two decades, although data are still lacking from many parts of the world including the Indian subcontinent, China, Africa and South America. Giant cell arteritis occurs in those aged 50 years and over and seems to mainly affect persons of northern European ancestry, whereas Takayasu arteritis occurs mainly in those aged under 40 years. By contrast, Kawasaki disease mainly occurs in children aged under 5 years and is most common in children of Asian ancestry, and IgA vasculitis occurs in children and adolescents. Although much less common than giant cell arteritis, the different forms of antineutrophil cytoplasmic antibody-associated vasculitis are being increasingly recognized in most populations and occur more frequently with increasing age. Behçet syndrome occurs most commonly along the ancient silk road between Europe and China. Much work needs to be done to better understand the influence of ethnicity, geographical location, environment and social factors on the development of vasculitis.

G-CSF and G-CSF-related vasculitis: a systematic review of the literature and intriguing future research perspectives.

Background: There are several case reports suggesting that G-CSFs may, in rare conditions, produce serious side effects, such as vasculitis. Materials & methods: A systematic search was conducted in Medline via PubMed, Embase and Cochrane Library to describe this unusual side effect to raise awareness among clinicians for early recognition and treatment. Results: Fifty-seven patients were analyzed. The most prevalent cancer type was breast cancer (47%). Long-acting G-CSF was used in 38 patients (67%). Only 47% of patients were treated with steroids. Conclusion: Although the benefit of G-CSF treatment outweighs the potential damage, oncologists should consider the possibility of triggering a vascular toxicity and try to identify patients at increased risk for this side effect.

Lay abstract Background: Several case reports suggest that a type of drug called granulocyte colony-stimulating factor (G-CSFs) may, in rare cases, produce serious side effects, such as vasculitis. Materials & methods: A systematic search was conducted to describe this unusual side effect. Results: Fifty-seven patients were analyzed. The most prevalent cancer type in which this side effect was observed was breast cancer (47%). Only 47% of patients were treated with steroids. The main symptoms, such as fever, chest/epigastric pain and general malaise, are nonspecific and cannot be used to diagnose the side effect; laboratory findings are suggestive of inflammation. Conclusion: Accurate assessment of what causes this adverse event is extremely important. Although the benefit of G-CSF treatment outweighs the potential damage, oncologists should consider the possibility of triggering vascular toxicity and try to identify patients at increased risk.

Localized Forms of Vasculitis.

PURPOSE OF REVIEW: To provide an updated review on epidemiology, clinical manifestations, diagnostic assessment, treatment, and prognosis of localized vasculitis, following the 2012 Revised International Chapel Hill Consensus Conference Nomenclature on single-organ vasculitis. RECENT FINDINGS: Localized, single-organ vasculitides encompass a group of rare conditions in which there is no evidence of concomitant systemic vasculitis. Most data on this topic derives from case reports and small case series. Although some aspects of these diseases, such as clinical manifestations and histologic findings, have already been extensively investigated, there is still a lack of robust data concerning the pathogenesis, epidemiology, and treatment. Localized vasculitides may have a wide range of clinical features depending on the organ affected. The inflammatory process may have a multifocal/diffuse or unifocal distribution. Diagnosis is usually based on histopathology findings and exclusion of systemic vasculitis, which may frequently pose a challenge. Further research on treatment is warranted.

Vasculitis damage index in Behçet's disease.

BACKGROUND: Vasculitis damage index (VDI) is a validated damage index for systemic vasculitis, and as Behçet's disease is considered one of systemic vascular disease we aimed to study the relationship of the vasculitis damage index to clinical manifestations and comorbidity in patients with Behçet's disease (BD) to determine if VDI could be used to assess damage in patients with BD. METHODS: A total of 109 patients with BD were recruited from the Rheumatology Department (outpatient and inpatient clinic), Cairo University Hospitals. All patients were subjected to full history taking, clinical examination, and routine laboratory investigations. Disease activity was assessed by the BD current activity form, and the VDI was calculated in all patients. The relationship of the VDI to the disease clinical manifestations was studied. Mann-Whitney and Kruskal Wallis tests were used to estimate differences in quantitative variables. Spearman correlation test was used to test for correlation between quantitative variables. RESULTS: In the current study, the VDI ranged from 1 to 10, with a mean of 3.5 ± 1.8. It was significantly associated with total thrombosis (P = 0.022); total neurological manifestations (P = 0.000), especially stroke and cranial nerve affection; uveitis (P = 0.005); avascular necrosis (AVN) (P = 0.015); osteoporosis (P = 0.01); impaired vision (P < 0.0001); cataract (P < 0.0001); and diabetes (P = 0.012). Generally, immunosuppressive treatment was significantly associated with VDI (P = 0.039), especially cyclophosphamide (P < 0.0001), biological agent (P = 0.008), chlorambucil (P = 0.003), and anticoagulant (P = 0.02). VDI was also significantly correlated with age (P = 0.033), disease duration (P = 0.029), and duration of eye involvement (P = 0.003). CONCLUSION: VDI is significantly associated with most disease parameters of BD, except for parameters such as mucocutaneous manifestations and uncomplicated venous thrombosis; however, further studies may be needed to establish BD-specific damage index.

Cardiovascular events and the role of accelerated atherosclerosis in systemic vasculitis.

The spectrum of inflammatory blood vessel diseases includes both atherosclerosis and the primary systemic vasculitides. Although the inciting triggers differ, significant overlap exists in the mechanisms that contribute to sustained inflammation and vascular damage in both entities. With improvement in therapeutics to control acute vasculitis leading to longer survival, cardiovascular morbidity and mortality has emerged as the leading cause of death for vasculitis patients. Cardiovascular events likely occur as a consequence of vasculitis, vascular damage from prior inflammation causing a sustained procoagulant state, and accelerated atherosclerosis. In this review, we discuss the latest evidence regarding risk of cardiovascular events in patients with major forms of primary systemic vasculitis, and review the mechanisms by which accelerated atherosclerosis may occur.

Clinical presentations and long term prognosis of childhood onset polyarteritis nodosa in single centre of Korea.

Childhood-onset polyarteritis nodosa (PAN) is a rare and systemic necrotising vasculitis in children affecting small- to medium-sized arteries. To date, there have been only a few reports because of its rarity. Thus, we aimed to investigate the clinical manifestations, laboratory findings, treatment, and long-term outcomes in patients with childhood-onset PAN and to evaluate the usefulness of the paediatric vasculitis activity score (PVAS). We retrospectively analysed the data of nine patients with childhood-onset PAN from March 2003 to February 2020. The median ages at symptom onset, diagnosis, and follow-up duration were 7.6 (3-17.5), 7.7 (3.5-17.6), and 7.0 (1.6-16.3) years, respectively. All patients had constitutional symptoms and skin manifestations, while five exhibited Raynaud's phenomenon. Organ involvement was observed in one patient. The median PVAS at diagnosis was 7 (range: 2-32). Prednisolone was initially used for induction in all patients, and other drugs were added in cases refractory to prednisolone. All patients survived, but three patients with high PVAS at diagnosis experienced irreversible sequelae, including intracranial haemorrhage and digital amputation. In conclusion, early diagnosis and treatment may minimise sequelae in patients with childhood-onset PAN. This study suggests that high PVAS score at diagnosis may be associated with poor prognosis.

Epidemiology of Scleritis in the United Kingdom From 1997 to 2018: Population-Based Analysis of 11 Million Patients and Association Between Scleritis and Infectious and Immune-Mediated Inflammatory Disease.

OBJECTIVE: To estimate 22-year trends in the prevalence and incidence of scleritis, and the associations of scleritis with infectious and immune-mediated inflammatory diseases (I-IMIDs) in the UK. METHODS: The retrospective cross-sectional and population cohort study (1997-2018) included 10,939,823 patients (2,946 incident scleritis cases) in The Health Improvement Network, a nationally representative primary care records database. The case-control and matched cohort study (1995-2019) included 3,005 incident scleritis cases and 12,020 control patients matched by age, sex, region, and Townsend deprivation index. Data were analyzed using multivariable Poisson regression, multivariable logistic regression, and Cox proportional hazards multivariable models adjusted for age, sex, Townsend deprivation index, race/ethnicity, smoking status, nation within the UK, and body mass index. Incidence rate ratios (IRRs) and 95% confidence intervals (95% CIs) were calculated. RESULTS: Scleritis incidence rates per 100,000 person-years declined from 4.23 (95% CI 2.16-6.31) to 2.79 (95% CI 2.19-3.39) between 1997 and 2018. The prevalence of scleritis per 100,000 person-years was 93.62 (95% CI 90.17-97.07) in 2018 (61,650 UK patients). Among 2,946 patients with incident scleritis, 1,831 (62.2%) were female, the mean ± SD age was 44.9 ± 17.6 years (range 1-93), and 1,257 (88.8%) were White. Higher risk of incident scleritis was associated with female sex (adjusted IRR 1.53 [95% CI 1.43-1.66], P < 0.001), Black race/ethnicity (adjusted IRR 1.52 [95% CI 1.14-2.01], P = 0.004 compared to White race/ethnicity), or South Asian race/ethnicity (adjusted IRR 1.50 [95% CI 1.19-1.90], P < 0.001 compared to White race/ethnicity), and older age (peak adjusted IRR 4.95 [95% CI 3.99-6.14], P < 0.001 for patients ages 51-60 years versus those ages ≤10 years). Compared to controls, scleritis patients had a 2-fold increased risk of a prior I-IMID diagnosis (17 I-IMIDs, P < 0.001) and significantly increased risk of subsequent diagnosis (13 I-IMIDs). The I-IMIDs most strongly associated with scleritis included granulomatosis with polyangiitis, Behçet's disease, and Sjögren's syndrome. CONCLUSION: From 1997 through 2018, the UK incidence of scleritis declined from 4.23 to 2.79/100,000 person-years. Incident scleritis was associated with 19 I-IMIDs, providing data for rational investigation and cross-specialty engagement.