Treatment of cutaneous calcinosis in limited systemic sclerosis with minocycline

Objectives: To evaluate the effect of minocycline as treatment for cutaneous calcinosis in limited cutaneous systemic sclerosis (IcSSc). Methods: Patients with IcSSc who had cutaneous calcinosis causing pain or ulceration, or both, were prescribed minocycline 50 or 100 mg daily regularly in an open label manner between November 1994 and April 2000. At routine clinical follow up the appearance of the calcinosis deposits was assessed clinically and radiographically, and the patients' assessment of the degree of discomfort, size, and frequency of ulceration was recorded. Demographic data, including disease duration, clinical features, and antinuclear antibody (ANA) titres, were also recorded. Results: Nine patients have been treated to date. Eight of the nine patients were ANA positive, five of whom were positive for anticentromere antibodies. Eight patients have shown definite improvement and seven patients continue to receive treatment. The frequency of ulceration and inflammation associated with the calcinosis deposits decreased with treatment. The size of the calcinosis deposits also decreased but was less dramatic than expected. Improvement occurred at the earliest after one month of treatment with a mean (SD) of 4.8 (3.8) months. The mean (SD) length of treatment was 3.5 (1.9) years. An unexpected effect was the darkening of the calcinosis deposits to a blue/black colour. Conclusions: Minocycline may be effective in the control of calcinosis in systemic sclerosis. A low dose only is required and appears to be generally well tolerated. The mechanism of action may be mainly through inhibition of matrix metalloproteinases and anti-inflammatory effects. Calcium binding properties and antibacterial actions may also have a role.