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![Figure](https://www.cmaj.ca/content/cmaj/176/3/321.1/F1.medium.gif)
Figure. A 45-year-old man with scleroderma presented with a 3-year history of blue skin discoloration on his legs, feet and gingival margin.
The patient had a long history of Raynaud's phenomenon, acid reflux disease and skin tightening over his fingers, hands, forearms and face. Five years earlier, he had received a diagnosis of diffuse scleroderma.
An early open-label trial of minocycline involving a small number of patients with early diffuse scleroderma had suggested the drug's efficacy in reducing skin tightness. Based on this report, the patient had been prescribed minocycline therapy by his rheumatologist 5 years before presentation. The patient reported noticing skin discoloration on his legs and feet over the last 3 years. There was no pruritus or pain, sclerodermatous thickening of skin on the legs or any sensory abnormalities. He also reported noticing pigmentation on the lower gingival margin.
Tetracycline and its analogues have traditionally been used for the treatment of acne; however, their role in inflammation and their therapeutic effect in diseases such as rosacea, bullous disorders, neutrophilic dermatoses, pyoderma gangrenosum, sarcoidosis, rheumatoid arthritis and scleroderma have been investigated. In contrast to earlier findings, a more recent larger study suggested that minocycline is not an effective therapy for systemic sclerosis.1
Long-term use of minocycline has been associated with non–dose-dependent blue-grey circumscribed pigmentation of clinically normal skin of the lower legs and mucosal pigmentation. Histologically, intracellular pigment is seen in the dermis and the subcutaneous tissue, which stains posi-tively for melanin and iron.
In one study, hyperpigmentation occurred in 41% of patients with rheumatoid arthritis who had been taking minocycline for more than 3 months (median onset 12 months).2 When not extensive, hyperpigmentation may at least partly regress after minocycline therapy is discontinued. Alexandrite laser therapy has been effective in treating minocycline-induced hyperpigmentation without scarring or hypopigmentation.
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Competing interests: None declared.