Patients with systemic lupus erythematosus (SLE) were evaluated using
a telephone questionnaire on the activity of various disease manifesta
tions during the seasons of the past year. The results were compared t
o those of patients with Behcet's disease (BD), using the same questio
nnaires, and analyzed in relation to the mean temperature, humidity, b
arometric pressure, and ultraviolet radiation (UVR) in the patient's l
ocation, obtained from the official Israeli Meteorological Service. It
was found that SLE patients had a tendency towards winter worsening o
f clinical manifestations, shown as increased incidence of joint pains
, weakness, fatigue, Raynaud's phenomenon, and rash, as well as increa
sed number of hospital admissions, sick leaves, and need to raise the
dose of medications. The symptoms of patients with BD were not correla
ted to seasons of the year, except for increased joint pains in autumn
and spring. We suggest that UVR accumulation might cause exacerbation
s in SLE patients several months after prolonged exposure to sunlight
in the summer.