Abstract

Lichen amyloidosis (LA) is the most common subtype of primary localized cutaneous amyloidosis, characterized by pruritic, hyperpigmented papules and plaques on the extensor surfaces of extremities, especially the shins. The disease is rare in Europe but more common in Southeast Asia. Pathogenesis involves the itch-scratch cycle, where chronic scratching causes keratinocyte damage and amyloid K deposition in the papillary dermis. Genetic mutations in OSMR and IL31RA genes affecting the IL-31 signaling pathway are associated with disease development. Diagnosis is confirmed by skin biopsy, where amyloid stains with Congo red and shows characteristic applegreen birefringence under polarized light.
Treatment aims to relieve symptoms and break the itch-scratch cycle. Traditional treatment modalities include potent topical corticosteroids, keratolytic agents, and phototherapy, but their efficacy is limited. Recently, dupilumab, an IL-4 and IL-13 receptor antagonist, has shown significant efficacy in treating refractory LA, relieving pruritus within weeks, and improving skin lesions within months. The presented case describes a 77-year-old man who achieved complete clinical remission with dupilumab therapy after nearly 20 years of treatmentresistant disease, supporting the use of dupilumab as a promising treatment option for severe LA.