In the GRAPPA 2020 Annual Meeting, held virtually this year, Dr. Philip Helliwell acknowledged that he, like many rheumatologists, struggled to understand a certain condition: SAPHO syndrome. According to Healio, SAPHO stands for synovitis, acne, pustulosis, hyperostosis, and osteomyelitis. But why is this condition so difficult to understand in patients with pustular psoriasis?
During the meeting, Dr. Helliwell explained that SAPHO syndrome was nothing short of an enigma. He describes the condition as rare and difficult to treat. In part, this is because the pathogenesis (disease development) is unknown and poorly understood. Additionally, there are a low number of patients. This makes holding clinical trials difficult, if not impossible.
The diagnostic criteria were first proposed about 26 years ago. These included arthritis or osteitis linked to acne, pustular psoriasis, or palmoplantar pustulosis; or sterile and axial osteomyelitis.
Unfortunately, these criteria may be out of date, leading to difficult with diagnoses. After 78 rheumatologists were surveyed, data shows that:
- 66 believed that diagnostic criteria needed to be updated.
- 46 believed the criteria were accurate to cases they saw. 32 did not feel as though the criteria were accurate.
This is not the only area of disagreement. Respondents also had difficulty narrowing down potential treatments for patients with SAPHO syndrome, which ranged from NSAIDs to DMARDs, antibiotics to steroid injections. Finally, respondents disagreed about what condition SAPHO syndrome was a subtype of. Potential results included psoriatic arthritis, spondyloarthritis, or its own separate condition altogether.
Moving forward, says Helliwell, change is needed. If rheumatologists want to better understand SAPHO syndrome:
“It would be worth looking at developing new criteria, as well as [having] a better look at the genetics [of SAPHO to] see how they relate to spondyloarthritis, psoriatic arthritis, and…generalized pustular psoriasis.”
According to the Genetic and Rare Disease Information Center (GARD), SAPHO syndrome is a rare condition which involves a combination of:
- Synovitis, or joint inflammation
- Pustulosis, or thick blisters (yellow) that contain pus on the palms of the hands and soles of the feet
- Hyperostosis, or excessive bone growth
- Osteitis, or bone inflammation
Currently, researchers do not know the cause of this condition. SAPHO syndrome, due to its symptoms, may be considered a skin or musculoskeletal condition. Additional symptoms include:
- Chest, bone, and joint pain
- Skeletal tumors
- Tendon and ligament inflammation
- Fluid retention
- Bone infections
- Abdominal pain
Learn more about SAPHO syndrome here.
Pustular psoriasis is a condition in which white blisters full of pus (called pustules) appear on the skin, surrounded by red patches and scaly skin. The pus does not signify an infection, nor is it contagious. For patients with pustular psoriasis, they may experience numerous triggers, from infections and stress to pregnancy and UV light exposure.
According to the National Psoriasis Foundation, there are three main types of pustular psoriasis, each with unique appearances and symptoms. These include:
- Acropustulosis, a rare form of psoriasis in which lesions and blisters appear on the fingers and toes. These painful lesions generally appear following infection or damage. Without treatment, acropustulosis can cause nail and bone deformities.
- Von Zumbusch pustular psoriasis, which appears suddenly. Pustules appear in a matter of hours, resulting in painful, tender, and glazed-looking red skin. Generally, this form is more prevalent in adults. Patients may experience fever, anemia, itching, dehydration, weight loss, and muscle weakness. When experiencing a flare, patients should visit their doctors – or be hospitalized – immediately. Without treatment, Von Zumbusch pustular psoriasis can be deadly.
- Palmoplantar pustulosis, in which lesions appear on the palms and soles of the feet. First, these pustules appear on top of reddened skin. However, they eventually crust over and turn brown.
Learn more about pustular psoriasis here.