Seasonal variations in manifestations and activity of systemic lupus erythematosus.

The purpose of the present study was to investigate a possible seasonal pattern in various clinical and laboratory manifestations in a group of systemic lupus erythamatosus (SLE) patients. One hundred and five SLE patients were followed up during a 4 yr period. Data on each of the clinical and laboratory variables examined, as well as the results of the disease activity index (SLEDAI), were plotted against the month during which they were obtained. Photosensitivity was the only variable to show a seasonal pattern, having higher scores during the summer months (1.04 +/- 0.16 in July vs 0.58 +/- 0.12 in December). We were unable to show seasonal patterns in any of the other variables examined. As a group, SLE patients do not show any significant seasonal pattern in disease manifestations and activity, except for photosensitivity. However, such a pattern may exist for the individual patient.