METHODS: This retrospective cross-sectional study uses data from the Malaysian Psoriasis Registry (MPR) from January 2007 to December 2018.
RESULTS: Of 21 735 psoriasis patients, 34 (0.16%) had coexistent LE. The male to female ratio among psoriasis patients with coexistent LE was 1:5.8 versus 1.3:1 in patients with psoriasis but without LE. Nearly 70% presented with LE preceding psoriasis. Psoriasis patients with LE had an earlier age of psoriasis onset (27.56 ± 11.51 versus 33.31 ± 16.94 years, P = 0.006), a higher rate of psoriatic arthropathy (26.5% versus 13.0%, P = 0.02), and a significantly greater impairment of quality of life (Dermatology Quality of Life Index >10; 57.6% versus 40.3%, P = 0.04) compared with psoriasis patients without LE. The majority (87.5%) had systemic LE. The incidences of lupus nephritis (72.7% versus 40%) and hematological abnormalities (50% versus 20%) were higher among patients with LE preceding psoriasis compared with those with psoriasis preceding LE. Antinuclear antibody and double-stranded DNA were positive in 59.4% and 28.1% of psoriasis patients with LE, respectively. Hydroxychloroquine triggered the onset of psoriasis in 7 (24.1%) patients. Patients with LE were more likely to receive systemic treatment for psoriasis compared with those without LE (30.3% versus 14.2%, P = 0.008).
CONCLUSIONS: Psoriasis patients with coexistent LE were uncommon, displayed a female preponderance, were more likely to have joint involvement, and had greater quality of life impairment than those without LE. LE preceded psoriasis in most of these patients, and systemic LE was the most common subtype.