Use of JAK Inhibitors in Lichen Planus: An Update

Abstract

Lichen planus (LP) is a chronic inflammatory disorder affecting approximately 1% of the population. It presents with a wide range of clinical manifestations, mainly involving the skin, mucosal surfaces, and skin appendages, and is often characterized by a relapsing course and variable response to treatment. Although several therapeutic strategies are available, many are off-label and show limited efficacy in resistant forms. Increasing evidence points to the central role of the JAK/STAT signaling pathway in the immunopathogenesis of LP, with cytokines such as interferon-gamma and interleukin-21 playing key roles in sustaining chronic inflammation. Based on this rationale, Janus kinase (JAK) inhibitors have recently been proposed as potential therapeutic agents in LP. This review explores the biological basis for their use and systematically summarizes the existing clinical evidence on the use of JAK inhibitors in cutaneous, mucosal, appendageal, and nail variants of LP. The preliminary data suggests favorable outcomes in many patients with difficult-to-treat disease, with an acceptable safety profile. Further prospective trials are needed to establish their definitive role in the management of LP.

Keywords: Janus kinase inhibitors; cutaneous lichen planus; lichen planus; oral lichen planus; therapy.

Figure 1

Pathogenesis of lichen planus.

Figure 2

Symmetric, polygonal, flat, purplish papules on the back of a young woman with cutaneous lichen planus.

Figure 3

Coexistence of hypertrophic lichen (white arrows) and atrophic lichen (black arrows) in a male patient.

Figure 4

Multiple, pinhead-like, erythematous papules in a patient with exanthematous lichen planus.

Figure 5

(A) White stripes of the oral mucosa in a patient with reticular oral lichen planus. (B) White plaques of the oral mucosa in a patient with non-erosive, plaque-type oral lichen planus. (C) Erosions of the lower gingiva in a male patient with erosive oral lichen planus. (D) Massive ulceration in a female patient with ulcerative oral lichen planus.

Figure 6

(A) Cicatricial alopecia in a woman with lichen planopilaris. (B) Destruction of the architecture of the nail in a female patient with nail lichen planus.

Figure 7

Mechanism of action of JAK inhibitors in lichen planus.