Diffuse nail dyschromia in black patients with systemic lupus erythematosus.

Diffuse dark blue-black chromonychia was observed in 17 of 33 (52%) black patients with systemic lupus erythematosus (SLE), but not in 47 non-SLE black patients. About half of these patients had active disease. A comparison was made between patients with SLE with chromonychia and those without but no distinctive clinical or laboratory variable differentiated the 2 groups. This pattern of nail hyperpigmentation has not previously been associated with SLE.