PHOTOSENSITIVITY IN LUPUS-ERYTHEMATOSUS, UV PHOTOPROVOCATION RESULTS COMPARED WITH HISTORY OF PHOTOSENSITIVITY AND CLINICAL FINDINGS

Photosensitivity, one of the presenting symptoms in lupus erythematosu s (LE), is still poorly defined and varying prevalence figures have be en reported. The possibility of a coexisting photodermatosis, especial ly polymorphous light eruption (PLE), has often not been taken into ac count. We report the results of ultraviolet A (UVA) and B (UVB) photop rovocation tests in 67 clinically photosensitive patients who had conf irmed discoid LE (DLE), systemic LE (SLE) or subacute cutaneous LE (SC LE). The results are compared with a detailed history of photosensitiv ity and with clinical and serological findings. A pathological photopr ovocation reaction, graded as weak, moderate or strong, was induced wi th either UVA or UVB in 69% of patients with LE, in 100% of those with SCLE, in 70% of those with SLE and in 64% of those with DLE, but in n one of 14 controls. Only 16% of the pathological reactions were strong and long-lasting, resembling LE lesions, while 48% were moderate or w eak and transient, clinically like PLE. Fifty-three per cent of the pr ovocation reactions which were biopsied showed a PLE-like histology or a non-specific inflammatory reaction, and most of them were clinicall y moderate or weak reactions of short duration. In the remaining, most ly clinically strong or long-lasting reactions, the histology was cons istent with LE. A history of sunlight sensitivity did not predict a pa thological photoprovocation result but a positive association between the presence of SSA/Ro or SSB/La antibodies and a pathological photopr ovocation reaction was found, We have shown that PLE coexists with LE and that both PLE- and LE-like lesions can be induced with UV radiatio n in LE patients.