Images of the month 3: The 'bull's head' sign of SAPHO syndrome.

Synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome is a rare, chronic, inflammatory disorder with cutaneous and osteoarticular manifestations.1 The aetiology of SAPHO syndrome is unknown and therefore treatment is tailored towards the individual. Non-steroidal anti-inflammatory drugs, bisphosphonates, corticosteriods, antibiotics, disease modifying anti-rheumatic drugs and biologics have all been used with variable success. © Royal College of Physicians 2019. All rights reserved.