Primary localized cutaneous amyloidosis

Primary localized cutaneous amyloidosis (PLCA) is a chronic itchy skin disorder associated with amyloid deposits in the superficial dermis. It is a purely cutaneous disease with no association with systemic forms of amyloidosis. Clinically, skin lesions comprise small, flat-top papules (lichen amyloidosis) or brown-gray macules (macular amyloidosis). PLCA is relatively common in South America and Asia, and some cases have an autosomal dominant family history (familial PLCA, FPLCA). The genetic basis of FPLCA involves mutations in the OSMR and IL31RA genes. Both belong to the family of interleukin (IL)-6 family cytokine receptors.