Cutaneous Kikuchi disease-like inflammatory pattern without lymph node involvement is associated with systemic disease and severe features in lupus erythematous: A case-control study.

Introduction: Kikuchi-Fujimoto disease (KFD) is a self-limited histiocytic necrotizing lymphadenitis sometimes affecting the skin. "Kikuchi disease-like inflammatory pattern" (KLIP) has been described in cutaneous lesions as similar pathological features in patients without lymph node involvement and as a potential clue for the diagnosis of lupus. We aimed to describe KLIP-associated clinical and immunological features in lupus patients with a retrospective case-control study.

Methods: Thirteen cases of KLIP were included as well as thirty-nine age- and sex-matched control lupus patients without KLIP. At the time of KLIP diagnosis, 4/13 patients (31%) had isolated cutaneous lupus erythematosus (CLE) and 9/13 had (69%) systemic lupus erythematosus (SLE) including 6 (46%) with severe haematological, lung, cardiac or renal disease. KLIP features were observed in skin biopsies of different clinical presentations.

Results: Compared with our control group, KLIP patients more frequently had SLE 9/13 (69%) versus 8/39 (21%) (OR 12.9; IC95% [2.86-58.2]; p = 0.0004) and more frequently severe SLE. Two out of four CLE exhibiting KLIP lesions (50%) developed severe SLE with cardiac or renal involvement after 12 and 24 months, respectively.Treatment with thalidomide 100 mg/day allowed rapid and complete clearance of cutaneous lesions in 6/6 KLIP patients. The need to use thalidomide tended to be more frequent in KLIP patients than in controls.

Conclusion: Our study suggests that KLIP features in lupus skin lesions are associated with SLE and severe systemic features. Despite a limited number of isolated CLE patients with KLIP features in the skin, this observation may warrant closer follow-up on patients with a higher risk of developing SLE.