Clinical characteristics of pediatric synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome: the first Chinese case series from a single center

Towards the definition of disease phenotypes in paediatric SAPHO syndrome: a national multicentric study

OBJECTIVES

The objective of this study was to confirm the presence of different disease phenotypes of paediatric SAPHO syndrome (pSAPHO) based on their skin manifestations in a large cohort of Italian patients.

METHODS

Patients with pSAPHO were enrolled in the Eurofever Registry and the data retrospectively analysed. The patients were categorized according to their skin manifestations into an acne - hidradenitis suppurativa (Acne-HS) group and a palmoplantar pustulosis - psoriasis vulgaris (PPP-PV) group and were compared with patients without skin manifestations (chronic non-bacterial osteomyelitis, CNO). Comparisons of frequencies between groups were performed using the χ2 test or the Fischer's exact test.

RESULTS

A total of 54 pSAPHO patients with skin manifestations (35 Acne-HS, 19 PPP-PV) were enrolled and compared with 167 patients with chronic recurrent multifocal osteomyelitis (CRMO). In the Acne-HS group, 82.9% were males, in the PPP-PV, 84.2% were females, while in the chronic non-bacterial osteomyelitis (CNO) group, no gender differences were observed (P < 0.0001). The three groups differed significantly with respect to age at disease onset: Acne-HS median 13.3 years, PPP-PV median 10.2 years, CNO median 9.5 years (P = 0.0001). An axial pattern was more frequent in the Acne-HS (91.4%) group and the PPP-PV group (89.4%) compared with in the CNO group (46%) (P < 0.0001). Both the Acne-HS (82.9%) and the PPP-PV (63.2%) groups required a biologic therapy more frequently than the CNO group (36.8%), but patients with Acne-HS presented with a refractory skin disease requiring steroids and other lines of treatment, while PPP-PV responded well to biologics.

CONCLUSION

Our data have identified two different phenotypes of pSAPHO based on skin manifestations, with different age of onset, gender, and response to treatments. These two groups have peculiar clinical features that differ from those of the CNO group. A new classification encompassing these phenotypes is warranted.

Long-term effectiveness of the combination of iguratimod and alendronate in SAPHO syndrome: a prospective cohort study

OBJECTIVE

To evaluate the long-term effectiveness of the combination of Iguratimod (IGU) and Alendronate for patients with Synovitis, Acne, Pustulosis, Hyperostosis and Osteitis (SAPHO) syndrome.

METHODS

A prospective cohort study was conducted on patients diagnosed with SAPHO syndrome at Peking University Third Hospital and Beijing Jishuitan Hospital from 2017 to 2024. The initial treatment regimen comprised a combination of IGU and Alendronate. Patients who were followed up for >2 years were included in our study. We collected demographic data, clinical symptoms, recurrence rates, treatment duration and overall response to therapy for all patients.

RESULTS

Seventeen patients were recruited for our cohort, with a median (IQR) follow-up of 2.91 (2.34) years. The mean treatment duration was 39.10 months. Among patients with osteoarticular involvement (17/17), 35.30% (6/17) achieved complete improvement without any recurrence, 11.76% (2/17) showed partial improvement and 52.94% (9/17) experienced intermittent flares. For patients with skin involvement (11/17), 63.64% (7/11) achieved complete improvement, 27.27% (3/11) had partial improvement and 9.09% (1/11) experienced intermittent recurrence. Notably, 88.26% (15/17) regained complete independence and resumed work, and 94.12% (16/17) experienced alleviation of anxiety and insomnia. By the end of last follow-up, 52.94% (9/17) had ceased treatment after a mean duration of 25.22 months and 22.22% (2/9) of them encountered recurrence.

CONCLUSION

The combination of IGU and Alendronate as initial treatment may be effective for the long-term management of SAPHO syndrome. ∼41% of the patients could discontinue treatment after more than two years without recurrence.

Therapeutic approaches for SAPHO syndrome from the perspective of pathogenesis: a review of the literature

Synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome is a rare autoinflammatory disease characterized by cutaneous manifestations and osteoarticular damage. The pathogenesis of SAPHO syndrome has not yet been elucidated, but studies have shown that the abnormal bone metabolism of patients with SAPHO syndrome is most likely due to localized infections that induce immune disorders in the body. Although no standardized treatment protocols exist, based on existing case studies and data from open studies, we propose that the treatment of SAPHO syndrome can be categorized into three areas according to the symptomatic manifestations of the disease: (1) control of focal infections using antibiotics and tonsillectomy; (2) administration of DMARDs to manage disease progression; and (3) bone remodeling therapy with bisphosphonates to address abnormal bone metabolism. Furthermore, a comprehensive treatment approach tailored to the clinical manifestations of the patient can effectively alleviate symptoms and enhance quality of life.

Efficacy and Safety of Bisphosphonates in Chronic Non-bacterial Osteomyelitis of the Mandible: A Systematic Review

Chronic non-bacterial osteomyelitis (CNO) of the mandible, often called diffuse sclerosing osteomyelitis (DSO) in Maxillofacial and Dental literature, is a rare condition characterized by sterile osteomyelitis affecting the mandible. This condition is part of the chronic recurrent multifocal osteomyelitis (CRMO)/synovitis, acne, pustulosis, hyperostosis, and osteomyelitis (SAPHO) spectrum. However, because mandibular involvement may present as unifocal disease, it deserves special attention. Unfortunately, the rarity of this disorder, along with a general lack of awareness, has led to numerous unnecessary and ineffective surgical interventions in the past. While some of these lesions may resolve on their own with only symptomatic management with NSAIDs, there is increasing evidence that lesions refractory to NSAIDs can respond well to bisphosphonates (BPNs). The authors conducted a systematic review following PRISMA guidelines to investigate the effectiveness of BPNs for CNO/SAPHO of the mandible and to assess potential adverse reactions, particularly medication-related osteonecrosis of the jaw (MRONJ). In this review, we identified one randomized controlled trial and nine case series describing the use of bisphosphonates in treating mandibular CNO/SAPHO. While heterogeneity among the studies precluded the extraction of statistically relevant information, BPNs are an effective treatment for mandibular CNO with minimal chance of jaw osteonecrosis and disturbance to the growing skeleton.

Paediatric SAPHO syndrome with pleural effusion: Case report of a unique finding in a rare disease

Synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome is a rare autoinflammatory disease characterised by bone inflammation and skin manifestations including acne, palmoplantar pustulosis, psoriasis, or hidradenitis suppurativa. SAPHO syndrome is considered on the same spectrum as chronic nonbacterial osteomyelitis/chronic recurrent multifocal osteomyelitis, the former often being the nomenclature in adults and the latter in children. The diagnosis is made on patterns of clinical manifestations and is a diagnosis of exclusion. While skin and bone manifestations are commonly described with SAPHO syndrome, pleural involvement is rare, and few cases have been described in the literature, especially in paediatric patients. Herein we present a 14-year-old female with a past medical history of hidradenitis supprtiva, eczema, psoriasis, and a prior episode of culture-negative osteomyelitis who presented to the emergency room with chief complaints of right-sided pain with inspiration and back pain. Exam revealed palmoplantar pustulosis, hidradenitis supprativa, psoriasis, and tenderness of vertebrae. Imaging showed a right-sided pleural effusion and multiple sites of osteitis. Laboratory evaluation revealed elevated inflammatory markers, an exudative pleural effusion with neutrophilic predominance, and no evidence of malignancy, infection, or immunodeficiency. The patient was diagnosed with SAPHO syndrome and treated with naproxen, methotrexate, and golimumab with significant improvement including resolution of the pleural effusion. Paediatric SAPHO syndrome is a rare disease that classically causes osteitis and skin manifestations. This case highlights that pleural effusion can be a rare manifestation of paediatric SAPHO syndrome. Patients with suspected SAPHO syndrome with respiratory symptoms should be evaluated for pleural effusion.

An improved understanding of pediatric chronic nonbacterial osteomyelitis pathophysiology informs current and future treatment

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disease that primarily affects children and young people. It can cause significant pain, reduced function, bone swelling, and even (vertebral body) fractures. Because of a limited understanding of its pathophysiology, the treatment of CNO remains empiric and is based on relatively small case series, expert opinion, and personal experience. Several studies have linked pathological NOD-kike receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome activation and the resulting imbalance between pro- and anti-inflammatory cytokine expression with CNO. This agrees with elevated pro-inflammatory (mostly) monocyte-derived protein signatures in the blood of CNO patients that may be used as future diagnostic and/or prognostic biomarkers. Recently, rare variants in the P2RX7 gene, encoding for an ATP-dependent transmembrane channel, were linked with increased NLRP3 inflammasome assembly and prolonged monocyte/macrophage survival in CNO. Although the exact molecular mechanisms remain unclear, this will inform future target-directed and individualized treatment. This manuscript reviews most recent developments and their impact on diagnostic and therapeutic strategies in CNO.

A statistical symptomatic evaluation on SAPHO syndrome from 56 cases of confirmed diagnosis and 352 cases of non-SAPHO involvement

OBJECTIVE

To report a statistical evaluation of symptomatology based on 56 cases of SAPHO syndrome and 352 non-SAPHO involvement cases, to propose a symptomatic scoring system in consideration of early warning for SAPHO syndrome.

METHODS

A cohort comprising 56 subjects diagnosed with SAPHO syndrome was reported, as well as 352 non-SAPHO involvement cases, including their chief complaints, skin manifestations, radiological findings, and laboratory tests. We systematically reviewed previous published five representative huge cohorts from different countries to conclude several specific features of SAPHO by comparing with our case series. The score of each specific index is based on respective incidence and comparison of two cohorts was performed.

RESULT

In terms of complaint rates, all subjects of two cohorts suffered from osseous pain, which appeared in the anterior chest wall, spine, and limb which were calculated. In respect to dermatological lesions, SAPHO patients suffered from severe acne, and other patients (82.14%) accompanied with palmoplantar pustulosis. Having received radiological examinations, most SAPHO subjects rather than non-SAPHO involvement cases showed abnormal osteoarticular lesions under CT scanning and more detailed information under whole-body bone scintigraphy. Differences also emerged in elevation of inflammation values and rheumatic markers like HLA-B27. Based on our cases and huge cohorts documented, the early warning standard is set to be 5 scores.

CONCLUSIONS

SAPHO syndrome case series with 56 subjects were reported and an accumulative scoring system for the early reminder on SAPHO syndrome was proposed. The threshold of this system is set to be 5 points. Key Points • Fifty-six patients diagnosed by SAPHO syndrome with detailed symptoms and radiological findings were reported. • Comparison was made between the 56 SAPHO patients and 352 non-SAPHO involvement cases. • An accumulative scoring system for the early reminder on SAPHO syndrome was proposed and the threshold of this system is set to be five points.

Clinical and imaging features of six Han patients with SAPHO syndrome

BACKGROUND

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a rare autoimmune disease characterized by skin or osteoarticular damage. SAPHO syndrome is often misdiagnosed or missed diagnosis due to lack of overall understanding of the disease by clinicians.

PURPOSE

To analyze the clinical symptoms and imaging features of six Han patients with SAPHO syndrome in order to provide reference for doctors to diagnose SAPHO syndrome.

MATERIAL AND METHODS

This study retrospectively analyzed the clinical data of six Han patients with SAPHO syndrome.

RESULTS

All six Han patients with SAPHO syndrome had severe acne or pustulosis of the hands and feet, and all of them had osteoarticular damage, including five cases involving the sternoclavicular joint. Some patients showed a specific and typical "bull's head" sign on 99mTc-labeled methylene diphosphonate bone imaging. Among the six patients recruited, there was one thoracic vertebra, one cervical vertebra, one sacroiliac joint, and one peripheral joint involvement. Two patients had limited activity due to severe osteoarticular damage.

CONCLUSION

Due to the atypical clinical symptoms of SAPHO syndrome, most patients will experience a tortuous and long diagnostic process, while a correct understanding and timely intervention of SAPHO syndrome are essential to improve the prognosis of patients.

Treatment and monitoring of SAPHO syndrome: a systematic review

BACKGROUND AND OBJECTIVES

Synovitis acne pustulosis hyperostosis osteitis (SAPHO) is a rare heterogeneous disease of unknown aetiopathology. Externally validated and internationally agreed diagnostic criteria or outcomes and, as a result, prospective randomised controlled trials in SAPHO are absent. Consequently, there is no agreed treatment standard. This study aimed to systematically collate and discuss treatment options in SAPHO.

METHODS

Following 'Preferred Reporting Items for Systematic Reviews and Meta-Analyses' guidance, a systematic literature search was conducted using PubMed, Scopus and Web of Science databases. Prospective clinical studies and retrospective case collections discussing management and outcomes in SAPHO involving five or more participants were included. Articles not published in English, studies not reporting defined outcomes, and studies solely relying on patient-reported outcomes were excluded.

RESULTS

A total of 28 studies (20 observational, 8 open-label clinical studies) reporting 796 patients of predominantly European ethnicity were included. Reported therapies varied greatly, with many centres using multiple treatments in parallel. Most patients (37.1%) received non-steroidal anti-inflammatory drugs alone or in combination. Bisphosphonates (22.1%), conventional (21.7%) and biological (11.3%) disease-modifying antirheumatic drugs were the next most frequently reported treatments. Reported outcomes varied and delivered mixed results, which complicates comparisons. Bisphosphonates demonstrated the most consistent improvement of osteoarticular symptoms and were associated with transient influenza-like symptoms. Paradoxical skin reactions were reported in patients treated with TNF inhibitors, but no serious adverse events were recorded. Most treatments had limited or mixed effects on cutaneous involvement. A recent study investigating the Janus kinase inhibitor tofacitinib delivered promising results in relation to skin and nail involvement.

CONCLUSIONS

No single currently available treatment option sufficiently addresses all SAPHO-associated symptoms. Variable, sometimes descriptive outcomes and the use of treatment combinations complicate conclusions and treatment recommendations. Randomised clinical trials are necessary to generate reliable evidence.

Skin manifestations help identifying different phenotypes of paediatric SAPHO syndrome

OBJECTIVES

to evaluate whether the heterogeneous skin manifestations might influence the disease presentation and outcome of a cohort of SAPHO children.

METHODS

the clinical, serological, imaging and therapeutic data of 14 SAPHO patients, followed between 2001 and 2022 at the Unit for Autoinflammatory diseases at the Gaslini Hospital, were reviewed. According to their cutaneous manifestations, patients were divided into 2 groups: the acne-hidradenitis suppurativa (HS) and the Palmo-Plantar Pustulosis (PPP) group. Data were retrieved from the Eurofever database.

RESULTS

all patients presented bone involvement characterized by Chronic Recurrent multifocal Osteomyelitis (CRMO): 8 patients presented acne-HS while 6 patients had PPP. In the PPP group, all patients were female, characterized by a prepuberal disease onset with osteoarticular manifestations, followed by the appearance of PPP in the following 6 months. This group responded well to the treatments. In the acne-HS group, 7/8 patients were male: the disease onset was characterized by skin manifestations in pubertal age, followed by osteoarticular manifestations in the following year. This group presented a severe refractory skin disease that required in most cases the addition of biological therapies. A literature review confirmed our data highlighting the association males-acne-puberal age and female-PPP-prepuberal age.

CONCLUSION

paediatric SAPHO patients should be mainly stratified according to their skin involvement. In fact, our data suggest that two different skin phenotypes may be identified in SAPHO: the first is constituted by prepuberal females with PPP and a prevalent osteoarticular involvement, while the second by puberal males with a difficult-to-treat acne-HS.

New insights on multigenic autoinflammatory diseases

Autoinflammatory diseases are disorders of the innate immune system, which can be either monogenic due to a specific genetic mutation or complex multigenic due to the involvement of multiple genes. The aim of this review is to explore and summarize the recent advances in pathogenesis, diagnosis, and management of genetically complex autoinflammatory diseases, such as Schnitzler's syndrome; adult-onset Still's disease; synovitis, acne, pustulosis, hyperostosis, osteitis syndrome/chronic recurrent multifocal osteomyelitis/chronic non-bacterial osteomyelitis; Adamantiades-Behçet's disease; Yao syndrome; and periodic fever with aphthous stomatitis, pharyngitis, and adenitis syndrome. The PubMed database was screened for relevant articles using free text words and specific search strings. The search was limited to English-language articles, reporting the results of studies in humans, published through March 2021. Evidence from literature suggest that these rare multigenic autoinflammatory diseases can present with different clinical features and the diagnosis of these diseases can be challenging due to a combination of nonspecific manifestations that can be seen in a variety of other conditions. Diagnostic delays and disease complications may occur due to low disease awareness and the lack of pathognomonic markers. The pathogeneses of these diseases are complex and in some cases precise pathogenesis is not clearly understood. Conventional treatments are commonly used for the management of these conditions, but biologics have shown promising results. Biologics targeting proinflammatory cytokines including IL-1, IL-6, TNF-α, IL-17A and IL-18 have been shown to ameliorate signs and symptoms of different multigenic autoinflammatory diseases.

Pro and contra: is synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) a spondyloarthritis variant?

PURPOSE OF REVIEW

The purpose of this review is to present the up-to-date evidence on the epidemiology, pathogenesis, musculoskeletal manifestations, and imaging of the synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome and to discuss its relationship with spondyloarthritis (SpA).

RECENT FINDINGS

SAPHO is a rare inflammatory disorder of bone, joints, and skin, with a worldwide distribution that predominantly affects the middle-age adults. The hallmark of the syndrome is a constellation of sterile inflammatory osteitis, hyperostosis, and synovitis involving the anterior chest wall, associated with acneiform and neutrophilic dermatoses, such as palmoplantar pustulosis and severe acne. The axial skeleton, sacroiliac, and peripheral joints can be involved in a similar fashion to SpA. The pathogenesis of the syndrome is multifactorial. The diagnosis is mainly based on the clinical and typical radiological features. The treatment approach is based on the off-label use of antibiotics, bisphosphonates, disease-modifying antirheumatic drugs, and anticytokine biologics.

SUMMARY

The SAPHO syndrome shares common features with SpA-related diseases, yet also shows some unique pathogenetic and clinical features. The nosology of SAPHO remains a subject of controversy, awaiting further research into the pathogenetic and clinical aspects of this syndrome. A better understanding of these aspects will improve the diagnostics and clinical care of patients with SAPHO.

Majeed Syndrome: A Review of the Clinical, Genetic and Immunologic Features

Majeed syndrome is a multi-system inflammatory disorder affecting humans that presents with chronic multifocal osteomyelitis, congenital dyserythropoietic anemia, with or without a neutrophilic dermatosis. The disease is an autosomal recessive disorder caused by mutations in LPIN2, the gene encoding the phosphatidic acid phosphatase LIPIN2. It is exceedingly rare. There are only 24 individuals from 10 families with genetically confirmed Majeed syndrome reported in the literature. The early descriptions of Majeed syndrome reported severely affected children with recurrent fevers, severe multifocal osteomyelitis, failure to thrive, and marked elevations of blood inflammatory markers. As more affected families have been identified, it has become clear that there is significant phenotypic variability. Data supports that disruption of the phosphatidic acid phosphatase activity in LIPIN2 results in immune dysregulation due to aberrant activation of the NLRP3 inflammasome and overproduction of proinflammatory cytokines including IL-1β, however, these findings did not explain the bone phenotype. Recent studies demonstrate that LPIN2 deficiency drives pro-inflammatory M2-macrophages and enhances osteoclastogenesis which suggest a critical role of lipin-2 in controlling homeostasis at the growth plate in an inflammasome-independent manner. While there are no approved medications for Majeed syndrome, pharmacologic blockade of the interleukin-1 pathway has been associated with rapid clinical improvement.