Macular amyloidosis

Primary localized cutaneous amyloidosis  refers to deposition of amyloid in apparently previously normal skin with no evidence of deposits in internal organs. There are three types of primary cutaneous amyloidosis: nodular cutaneous amyloidosis, macular amyloidosis and lichenoid amyloidosis.  Macular and lichenoid forms of primary cutaneous amyloidosis occur relatively commonly and are associated with pruritus and friction. Macular amyloidosis is the commonest form of primary localized cutaneous amyloidosis; its etiology remains unclear. Macular amyloidosis is seen most frequently on the upper back, and is characterized by irregular pigmentation and pruritus.