- Synovitis -- inflammation of the joint lining (synovium), typically manifest as warmth, tenderness, pain, swelling, and stiffness of involved joints (arthritis).
- Acne -- a familiar skin condition featuring tiny areas of inflammation with pus formation at the hair follicles, most commonly on the face and upper back.
- Pustulosis -- 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 -- abnormal excessive growth of bone. The hyperostosis of the SAPHO syndrome frequently is located at the points of the bone where tendons attach.
- Osteitis -- 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.
SAPHO syndrome, it is thought, may be related to the group of arthritis conditions which typically affect the spine called the spondyloarthropathies and which include ankylosing spondylitis and Reiter syndrome.
The eponym SAPHO is pronounced "saffo" like the name of the ancient Greek poet Sappho (whose concise intense lyric poetry was so superb that two centuries after her death Plato called her the tenth muse).