How to classify Raynaud's phenomenon. Long-term follow-up study of 73 cases.

Raynaud's phenomenon without an underlying cause was diagnosed in 96 consecutive patients in 1978 to 1979. Seventy-three patients were available for long-term follow-up. They were classified on initial evaluation as having primary Raynaud's phenomenon (49 patients) when no clinical, laboratory, or serologic abnormality was detected, and as having suspected secondary Raynaud's phenomenon when at least one finding was abnormal. Re-evaluation was performed in 1984 to 1985 after an average duration of Raynaud's phenomenon of 14.9 +/- 12 years. The average duration of the follow-up from initial to final evaluation was 4.7 +/- 1 years. On final evaluation, none of the 49 patients with an initial diagnosis of primary Raynaud's phenomenon had evidence of secondary Raynaud's phenomenon, whereas 14 of the 24 patients with suspected secondary Raynaud's phenomenon had a definite diagnosis. Among them, there were 13 connective tissue diseases. The study proved that Raynaud's phenomenon without an underlying cause must be followed up for more than two years, contrary to what was recommended previously, before it can be rightly diagnosed as primary Raynaud's phenomenon. Moreover, the results suggested that, in order to distinguish early primary Raynaud's phenomenon from suspected secondary Raynaud's phenomenon, a simple and noninvasive evaluation is sufficient. In this study, the evaluation included history and clinical examination, tests for antinuclear antibodies, radiography of hands, chest roentgenography, and nailfold capillary microscopy.