Abstract
Pustulotic arthro-osteitis is a rare disease involving the skin and musculoskeletal system that was first described by Sonozaki. Onset is frequently seen at age 30–40. The prevalences between the sexes are similar. Palmoplantar pustulosis and sternoclavicular joint involvement are the most typical findings. It may be difficult to distinguish seronegative spondyloarthropathies and SAPHO syndrome due to sacroiliac joint, vertebral column and peripheral joint involvement. Arthritis being non-erosive and short-lived in character and the absence of deformity or contracture in the joints are significant clinical characteristics. Anti-inflammatory and immunesuppressive drugs are used in the treatment of the disease, the course of which involves remission and flare-ups. We describe the case of a 43-year-old male patient diagnosed with pustulotic arthro-osteitis.
Introduction
Pustulotic arthro-osteitis (PAO) is a relatively rare disease, the etiology of which has still not been fully clarified. Yamamato et al. explained the pathogenesis of PAO using an inflammation and hyperossification model. Joint and skin involvement can be triggered or caused to flare up by infections such as tonsillitis, dental infections, sinusitis and osteomyelitis (1). Migration to the skin and joints of T cells triggered by focal infection leads to the release of cytokines such as IL-1, TNF-
Palmoplantar pustular lesions in the plantar region on the feet (a). Histological appearance of pustule containing lymphocytes and histiocytes, together with hyperplasia in the epidermis and vascular proliferation in the superficial dermis (b).
The characteristic features of the disease are anterior chest pain associated with sternoclavicular joint (SCJ) involvement, and pustular lesions in the palms of the hands and soles of the feet. Several different drugs have been tested in the treatment of PAO due to the inflammation implicated in the pathogenesis. Analgesic and anti-inflammatory drugs are used in symptomatic treatment of Sonazaki syndrome. Other therapeutic options include immunosuppressives and sulfasalazine [2]. Improvement in joints other than the SCJ was observed with colchicine therapy in our patient, and improvement in cutaneous lesions was achieved with methotrexate.
Symptoms in the SCJ resolved entirely following betamethasone injection. In this report, we describe a patient with rare PAO and the treatment administered in the presence of SCJ involvement.
A 43-year-old man presented to our hospital with pain in the lumbar region and anterior chest wall. The lumbar pain was inflammatory in character, involved morning stiffness and persisted for more than 1 hour. No characteristics were determined at systemic interview or in his history. Physical examination revealed pustular lesions in the palmar and plantar regions of both hands and feet (Fig. 1a). The patient had no history of psoriasis, and nail evaluation was normal. Sensitivity and swelling were present in the anterior chest wall, the left first costosternal junction and at the level of the SCJ. Pain and restriction were determined with the sacroiliac pain provocation test. At laboratory examination, erythrocyte sedimentation rate (ESR) was 24 mm/h, C-reactive protein (CRP) 0.11 mg/dl and HLA B27. No pathology was determined in other routine biochemical parameters. Histopathological examination of the cutaneous pustular lesions revealed hyperplasia in the epidermis and vascular proliferation and lymphocytes/histiocytes in the superficial dermis (Fig. 1b). Magnetic resonance imaging (MRI) of the sternoclavicular and sacroiliac joints revealed signal changes compatible with edema in the bones constituting the left SCJ, surrounding soft tissue and the left sacroiliac joint (Figs 2a–b). Involvement was determined in the first costosternal joint and SCJ at whole body technetium-99 m diphosphonate scintigraphy.
Active sacroiliitis (a) in the left sacroiliac joint at coronal STIR and sternoclavicular joint osteitis at coronal fat suppression imaging (b).
The patient was diagnosed with pustulotic arthro-osteitis (Sonozaki syndrome) and was started on indomethacin 150 mg/day and colchicine 1 mg/day. At control examination after 1 month, the inflammatory back pain and morning stiffness had completely resolved, but while there had been a decrease in pustulotic lesions and pain in the left sternoclavicular joint, these still persisted. Seven milligrams of betamethasone was injected into the SCJ with ultrasound guidance, and 15 mg methotrexate was added to treatment. The patient is still receiving combination therapy.
PAO is a rare disease first described by Sonozaki et al. [3]. It was first thought to be associated with psoriasis, but today it is included in the seronegative spondyloarthropathies group unrelated to HLA B27 [4]. Laboratory findings in PAO are not specific. Increases may be seen in CRP and ESR, although these were normal in our case.
Osteitis in the anterior chest wall accompanies palmoplantar pustulosis in PAO [1]. Palmoplantar pustulosis is a skin disease frequently occurring in the 3
Musculoskeletal involvement in PAO is most commonly seen in the SCJ, with periosteal and endosteal ossification accompanying inflammation. Other frequently affected regions include the spinal column and the sacroiliac and peripheral joints. Sacroiliac joint involvement was reported at a level of 13% by Sonozaki et al. [3]. In our case, SCJ involvement was identified through bone scintigraphy and accompanied sacroiliac joint involvement determined at MRI.
PAO must be differentiated from other types of seronegative spondyloarthropathies and SAPHO (synovitis, acnes, pustulosis, hyperostosis and osteitis) syndrome. The SCJ, which is frequently involved in PAO patients, is affected in less than 15% of seronegative spondyloarthropathies. Rare SCJ involvement and HLA B27 negativity distinguish PAO from seronegative spondyloarthropathies. It is difficult to distinguish between PAO and psoriasis on the basis of skin findings. However, involvement seen in the proximal interphalangeal joint, the distal interphalangeal joint and the joint of the lower extremities in psoriatic arthritis can assist with differential diagnosis [2]. We suspected PAO rather than psoriasis in our patient on the basis of HLA B27 negativity, absence of joint involvements typical of psoriatic arthritis and typical anterior chest wall involvement.
SAPHO syndrome is a clinical entity consisting of a combination of osteoarticular (synovitis, hyperostosis and osteitis) and cutaneous lesions (acne and pustulosis). Cutaneous lesions seen in SAPHO include palmoplantar pustulosis, acne and hidradenitis suppurativa. Propionibacterium acnes is frequently responsible for acne lesions. Osteoarticular findings include osteolysis, erosion, osteitis, arthritis, hyperostosis and osteosclerosis. A bull-horn sign is seen in the anterior chest wall at scintigraphy. Intense osteomyelitic changes in SAPHO distinguish it from PAO [1].
The disease exhibits a chronic course in the form of flare-ups and remission. Analgesics and nonsteroid anti-inflammatory drugs are mainly used in treatment. Other therapeutic options include corticosteroids,colchicine, sulphasalazine, methotrexate cyclosporine and dapsone [2, 3, 6]. Murakami et al. recently administered cefcapene pivoxil hydrochloride (a 3
In conclusion, PAO is rare and may be confused with other diseases causing similar symptoms. Early diagnosis of this syndrome can obviate unnecessary treatments and improve patients’ quality of life.
Conflict of interest
The authors declare that they have no conflict of interest.