Osteomyelitis complicating scleroderma digital ulcers

Skin ulcers are very frequent in scleroderma (SSc), often complicated by local infection; the latter may be responsible for osteomyelitis (OM) of underlying bone. We retrospectively investigate the prevalence of OM in our SSc patients. The study included 248 SSc patients (M/F 21/227, mean age 61 +/- 13.5 SD years) followed at our Rheumatology Unit for a mean time period of 60.8 +/- 20.9 SD months. Patients with infected skin ulcers were carefully evaluated for complicating OM, which was diagnosed on the basis of typical clinical symptoms, laboratory, and radiological alterations. Skin ulcers were observed in 119/248 (48 %) SSc patients, more frequently digital ulcers (110/119, 92 %). These patients presented a significantly lower mean age (59 +/- 14.5 SD vs. 64 +/- 12.2 SD years; p = 0.005) and a lower percentage of anticentromere antibodies (40/119, 33.6 %, vs. 66/129, 51.2 %; p = 0.007) compared with those without ulcers. The prevalence of OM in the entire SSc patients' series was 7.7 % (19/248); it was invariably found in the setting of patients with infected digital ulcers, showing a surprisingly high percentage of underlying bone involvement (19/45, 42 %). The OM was localized at the hands in 14 patients and feet in 5; moreover, the most frequently isolated pathogens from infected digital ulcers were Staphylococcus aureus and Escherichia coli. Finally, patients with OM presented a significantly lower mean age (p < 0.016) and higher percentage of anti-Scl70 autoantibodies (p < 0.0128) compared to those without. We firstly demonstrated, in a large cohort of SSc patients, high prevalence of OM, invariably associated to infected digital ulcers, which represent the main predisposing condition for the development of such a harmful complication.