Background/Purpose:   Discoid lupus lesions occur in 20% of patients with SLE at some point in their disease course, and are often resistant to therapy. Atrophy, scarring, and pigmentation are often observed consequences. Recently poor response to hydroxychloroquine has been reported among SLE patients as compared with discoid lupus erythematosus (DLE) patients without SLE.   

The purpose of this study was to evaluate clinical outcome of active discoid lesions in patients with SLE and examine associated features of active discoid lupus..

Methods:   Patients with active discoid lupus were identified from the University of Toronto lupus clinic, a longitudinal observational cohort study of patients with SLE diagnosed on the basis of 4 ACR criteria or 3 criteria and a biopsy positive for lupus. For each patient, information on time of resolution and chronic changes of discoid lupus lesion were obtained from the database and confirmed through chart reviews. Associated features studied included demographic features, smoking, and disease activity (SLEDAI-2K). Descriptive statistics are used to describe the study population.

Results: 68 patients with active discoid lupus were identified from among 723 inception patients (9.4%). which represented 15% of the total number of patients who had any lupus rash. The age at diagnosis of SLE was 37.2 ± 11.9 years while age at diagnosis of DLE was 39.6-11.9. 59 (86.8%) were female and 41 (60.3%) were Caucasian.   30 (44.1%) patients were smokers. SLEDAI-2K was 8.66 ± 7.72 at discoid onset and adjusted mean SLEDAI was 7.51 ± 6.68. 43 (63.2%) patients were on steroid during the episode with mean steroid dose of 16.8 ± 11.6 mg/day.  56 (82.4%) were on antimalarial agents while 18 (26.5%) were on immunosuppressive agents. During their follow up 68 patients had a total of 82 episodes of DLE. Each episode lasted for 1.77 ± 2.10 years. SLE duration at discoid start is 2.3 ± 4.1 years. Pre-existing scars from previous active DLE were present in 21 (30.9%) patients while 11 (16.2%) patients developed new scars during episode and 36 (52.9%) patients never developed scars.

Conclusion: Discoid lupus is a common rash among SLE patients. SLE patients with DLE had active lupus and were taking significant doses of steroid. The duration of the discoid episode was 1.77 ± 2.10 years and 47.1% of patients developed scars.