Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis (SAPHO): An Interesting Clinical Syndrome

SAPHO syndrome: current clinical, diagnostic and treatment approaches

This review provides an overview of SAPHO (Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis), a rare autoinflammatory disease that primarily affects bones, skin, and joints. We conducted a search on Medline/PubMed using keywords such as SAPHO syndrome, chronic recurrent multifocal osteitis/osteomyelitis, and related terms. SAPHO syndrome is rare, with a reported frequency of 1 in 10,000 in the Caucasian population. However, the actual incidence of SAPHO syndrome is unknown, and the incidence of the disease is likely higher. The pathogenesis of SAPHO syndrome remains incompletely understood. Current evidence suggests that SAPHO results from a complex interplay between immune dysregulation, genetic susceptibility, and environmental factors. It's not clear if SAPHO syndrome is an autoimmune disease or an autoinflammatory disease, but current evidence suggests that it's more likely an autoinflammatory disease because of things like neutrophil hyperactivity, fewer natural killer (NK) cells, high levels of interleukin (IL)-1, and a good response to treatments that block IL-1. Osteo-articular (OA) involvement is a key clinical feature of SAPHO. It affects the anterior chest wall, axial skeleton, peripheral joints, mandible, long bones of the extremities, and pelvis. Dermatological involvement is a common target in SAPHO, with lesions observed in 60-90% of cases. Common skin lesions include psoriasis and acne, with hidradenitis suppurativa and neutrophilic dermatoses being less commonly seen. Other clinical findings include constitutional symptoms caused by systemic inflammation, such as fever, weight loss, and fatigue. There is no specific laboratory finding for SAPHO syndrome. However, during active disease, there may be an increase in positive acute phase markers, such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), complement levels, mild leukocytosis, and thrombocytosis. Diagnosis is crucial for SAPHO syndrome, which lacks a specific diagnostic finding and is often underrecognized. A comprehensive evaluation of a patient's medical history and physical examination is crucial. Treatment options include non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, conventional and synthetic disease-modifying agents (cDMARDs and sDMARDs), biological therapies, bisphosphonates, and antibiotics. Biological treatments have emerged as a viable alternative for SAPHO patients who do not respond to conventional treatments.

The role of cytokines in the pathogenesis of SAPHO syndrome

SAPHO syndrome is a complex inflammatory disorder affecting the skin and bones, characterized by osteomyelitis, acne, and pustulosis. Cytokines play a pivotal role in the pathogenesis of SAPHO syndrome, especially in inflammatory responses and immune regulation. This article reviews the cytokines involved in the pathogenesis of SAPHO syndrome, such as tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), IL-6, IL-10, and transforming growth factor-β (TGF-β), and discusses their potential as intervention points for treatment. These findings elucidate the intricate immune regulatory network of SAPHO syndrome and provide a theoretical foundation for the development of new targeted therapeutic strategies.

Successful Treatment of Refractory Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis (SAPHO) Syndrome with Baricitinib, a Janus Kinase Inhibitor

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome, a rare immune-mediated inflammatory disease, poses diagnostic and therapeutic challenges owing to its multi-system involvement, high heterogeneity, and lack of specific laboratory tests. Additionally, lacking evidence-based treatment recommendations, with the primary approach focusing on symptomatic relief. Herein, we report the case of a 32-year-old Chinese woman who presented with recurrent, generalized multiple osteoarticular pain lasting over one year and skin erythema pustulosis for 11 months. Traditional treatments, including non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, disease-modifying antirheumatic drugs (DMARDs), and other traditional approaches, yielded no significant effects. Despite the prior use of adalimumab and acitretin capsules, the treatment remained unsatisfying, especially regarding the skin lesions. Considering the complex pathogenesis of SAPHO syndrome, the patient was orally administered baricitinib (2 mg), a Janus kinase (JAK) inhibitor, twice daily. A notable improvement in both skin lesions and osteoarticular pain was observed within two weeks of treatment initiation. Subsequently, the dosage of baricitinib was halved and continued for an additional three months, during which regular follow-ups revealed neither disease recurrence nor adverse effects. Collectively, the successful treatment of refractory SAPHO syndrome with baricitinib presents a promising implication for addressing the therapeutic challenges of this rare autoimmune condition, offering a potential breakthrough in managing its complex manifestations.

Unusual cause of inflammatory backache: SAPHO syndrome

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) is a rare chronic inflammatory disease that develops in adults. We present a case of SAPHO syndrome in a 37-year-old male presenting with gradually worsening back and neck pain for a 7-year period. The episodes were preceded by a history of pustular skin eruptions, which first appeared on the upper trunk and then involved his face and were pustular and scarring. The purpose of presenting this case report from Iraq is to raise awareness about this rare condition, which is frequently misdiagnosed and under-recognized.

Beyond the Acne

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) is a relatively rare and often underdiagnosed disorder characterized by chronic inflammation affecting the bones, joints, and skin. While the precise cause of SAPHO syndrome remains elusive, multiple factors such as genetics, immunological dysregulation, and bacterial influences have been implicated in its pathogenesis. One notable aspect of SAPHO syndrome is the wide variability of symptoms experienced by afflicted individuals. A diverse array of osteoarticular manifestations may be observed, with common sites of involvement including the anterior chest wall, sacroiliac joints, and peripheral joints. Concurrently, patients often present with various skin disorders, such as palmoplantar pustulosis or acne, further adding to the complexity of the syndrome's clinical presentation. Treatment strategies for SAPHO syndrome primarily focus on managing symptoms and improving the quality of life for affected individuals. Nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, methotrexate (MTX), and tumor necrosis factor (TNF) inhibitors are considered to modulate the immune response and provide relief. One of the challenges encountered in diagnosing SAPHO syndrome is its potential overlap with other related conditions, leading to diagnostic confusion and difficulties. Distinguishing SAPHO syndrome from similar entities can be complex, requiring a comprehensive evaluation of clinical features, imaging studies, and laboratory investigations. We would like to share an intriguing case involving a 28-year-old woman who arrived with perplexing symptoms of pain in her bilateral hands and feet, her lower back, and acne in the bilateral upper arms and thighs. Through a comprehensive workup, the underlying SAPHO syndrome was uncovered, and it was effectively managed using adalimumab.