SAPHO syndrome is a chronic disorder that involves the skin, bone, and joints. SAPHO is an acronym for the combination of synovitis, acne, pustulosis, hyperostosis, and osteitis.
Synovitis means inflammation of the joint lining (synovium). Typically, this is manifests as warmth, tenderness, pain, swelling, and stiffness of involved joints (arthritis).
Acne is a skin condition featuring tiny areas of inflammation with pus formation at the hair follicles. Acne occurs most commonly on the face and upper back.
Pustulosis is a very inflammatory skin condition resulting in large fluid-filled blister-like areas (pustules), typically on the palms of the hands and/or the soles of the feet. The skin of these areas peels and flakes (exfoliates).
Hyperostosis means abnormal excessive growth of bone. The hyperostosis of the SAPHO syndrome frequently is located at the points of the bone where tendons attach, generally in the chest wall.
Osteitis means inflammation of the bone. Patients with SAPHO syndrome can develop inflammation of the sacroiliac joints (sacroiliitis) as well as inflammation of the spine (spondylitis) which leads to stiffness and pain of the neck and back.
What causes SAPHO syndrome, and what are risk factors for developing it?
The precise cause of SAPHO syndrome is not known. It is felt that the tendency toward developing SAPHO syndrome can be inherited.
Genetic predisposition is suggested by the higher prevalence of HLA-B27, an inherited blood marker, in patients with SAPHO syndrome.
Is SAPHO syndrome related to other joint conditions?
Some researchers feel that the SAPHO syndrome is related to the group of arthritis conditions that typically affect the spine, called the spondyloarthropathies.
For further information, please read the Ankylosing Spondylitis and Reactive Arthritis articles.
What are symptoms and signs of SAPHO syndrome?
SAPHO syndrome causes inflammation of joints with pain, stiffness, swelling, warmth, and redness. Joints affected can be spinal or away from the spine (peripheral joints) such as the fingers, wrists, or knees.
Acne of the skin and pustules of the palms of the hands and soles of the feet are characteristic.
SAPHO and related conditions have three stages of progression, which are described as :
- Costoclavicular ligament ossification.
- Arthropathy of the sternoclavicular joint, osteitis of the medial end of clavicle, 1st rib and sternum as well as hypertrophy of the costal cartilages.
- Osteitis, hyperostosis and hypertrophy of the medial ends of the clavicles, sternum and upper ribs and ultimately ankylosis.
Non specific but can be suspected if present with the other clinical findings
- sternoclavicular joint: most common location of involvement, with osteitis and hyperostosis
- osteosclerosis of vertebral bodies
- long bones: metaphyseal osteosclerosis and osteolysis
How is SAPHO syndrome diagnosed?
SAPHO syndrome is diagnosed clinically by identifying the characteristic features of the syndrome including synovitis, acne, pustulosis, hyperostosis, and osteitis.
The blood test marker antigen HLA-B27, when present, supports the diagnosis.
What is the treatment for SAPHO syndrome?
Treatment of patients with SAPHO syndrome is directed toward the individual symptoms that are present. Generally, treatment involves medications that reduce inflammation in the particular tissues affected.
Examples of medications that are used for inflammation include nonsteroidal anti-inflammatory drugs (NSAIDs, such as aspirin, ibuprofen [Advil, Motrin], and naproxen [Aleve]) and cortisone medications (either in the form of topical creams, tablets, or by injection into the involved area).
Topical cold applications can also help reduce inflammation in some tissues.
For patients with persisting joint symptoms, both sulfasalazine (Azulfidine) and methotrexate (Rheumatrex, Trexall) have been tried with varying degrees of success.
Newer biologic medications, including infliximab (Remicade), have also been used successfully.