Clinical, Histopathological and Outcome Analysis of Five Patients With Lichenoid Eruption Following Anti-Tumor Necrosis Factor-Alpha Therapy for Ankylosing Spondylitis: Report of One Case and Review of the Literature.

Tumor necrosis factor-alpha (TNF-ɑ) inhibitors have become the mainstay of therapy for a wide range of autoinflammatory diseases, despite concerns regarding dermatological adverse reactions. In this paper, we describe the clinical and histological findings and outcome of a case of lichenoid eruption (LE) following adalimumab therapy for ankylosing spondylitis (AS) and review four earlier reports concerning this rare clinical association. The time of onset varied considerably (three weeks to 52 months) and lesions varied within the clinical spectrum (from typical lichen planus to psoriasiform), but all had LE-compatible histology, with acanthosis, necrotic keratinocytes and lymphocytic infiltrate as hallmarks. Most patients (3/5) improved with treatment and one experienced full recovery, while in one case the lesions persisted. TNF-ɑ has been implicated in the pathogenesis of lichen planus, making it difficult to explain how TNF-ɑ antagonists can induce lichenoid reactions. The appearance of LE may in some cases justify cessation of therapy.