[Evaluation of the past history of chilblain in cases of systemic lupus erythematosus (SLE) and its similar diseases].
We sent out a questionnaire to 47 patients of SLE and its similar diseases as to their past histories of chilblain. The results of the patients were compared to those of 141 cases of control. Although the percentage of cases who had revealed chilblain frequently (40.0%) and the age of chilblain onset (mean: 10.8 years old) in SLE group were not significantly different from those of control (28.4% and 12.4 years old, respectively), the chilblain which SLE patients developed had some characteristics compared to that of control, (1) higher incidence of chilblain episodes, (2) longer duration until cure, (3) more liability that chilblain leads to erosion or ulceration and (4) frequent occurrence of chilblain in the other seasons than winter. Especially SLE patients with the characteristic of (4) had higher association rates of Raynaud's phenomena, chilblain LE and livedo, suggesting disorder of peripheral circulation. It was also revealed that females are generally more liable to develop chilblain than males (females: 40.0%, males: 13.1%). Those results suggest some important relationship between chilblain and LE lesions. It is supposed that chilblain with the characteristics described above may possibly be transformed into LE lesions.