SAPHO Syndrome

SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis and osteitis) is a chronic inflammatory disease that mainly affects the osteoarticular system. Its epidemiology, etiopathogenesis, symptomatology, diagnosis and treatment are detailed below:


SAPHO syndrome is a rare disease of unknown incidence, although it is estimated to affect less than 1 in 10,000 people. It affects males and females equally, and usually debuts in early adulthood.


The exact cause of SAPHO syndrome is not completely known. It is thought to be an autoinflammatory disease, in which the body's immune system mistakenly attacks healthy tissues. Activation of the NLRP3 receptor has been found to be present in some SAPHO patients, suggesting a role for inflammation and activation of the immune system in the pathogenesis of this disease.


SAPHO syndrome is characterized by chronic osteoarticular pain associated with inflammation of the skin (acne, pustulosis) and subcutaneous tissue. Patients may present with skin lesions in the form of reddish, scaly plaques, and pain and inflammation in joints, muscles and bones, especially in the spine and pelvis. Other organs such as the gastrointestinal tract and lungs may also be affected.


Diagnosis of SAPHO syndrome is based on clinical and radiological findings. Patients usually present with chronic osteoarticular pain, associated with typical skin lesions and characteristic radiological findings such as hyperostosis and osteitis. Laboratory studies may be normal or show signs of mild to moderate inflammation.


Treatment of SAPHO syndrome is based on the control of symptoms and inflammation. Nonsteroidal anti-inflammatory drugs (NSAIDs) are used as the first line of treatment, and in some cases oral or intravenous corticosteroids may be necessary. In patients with disease refractory to NSAID and corticosteroid therapy, biologic drugs such as tumor necrosis factor-alpha (TNF-α) inhibitors and interleukin-1 (IL-1) inhibitors have been used successfully. Bisphosphonate therapy has also been used for the treatment of hyperostosis and osteitis.