What is Pinch purpura around eyelids is one of the most common finding in and explain in detail?
Amyloidosis is a generic term, originally coined by Rudolf Virchow in 1854, which denotes extracellular deposition of a proteinaceous substance, amyloid composed of one of a family of biochemically unrelated proteins.Amyloidosis can be classified as systemic and cutaneous amyloidosis. Systemic amyloidosis is classified into primary and secondary. Primary systemic amyloidosis is a rare disorder. Wilks in 1856, was the first to describe primary systemic amyloidosis. Primary systemic amyloidosis may be idiopathic or myeloma associated. Primary and myeloma-associated systemic amyloidosis typically involve the tongue, hea, gastrointestinal tract, skeletal and smooth muscle, carpal ligaments, nerves, and skin. Cutaneous involvement is seen in 40% patients with AL amyloidosis. Cutaneous manifestations depend on the site of amyloid deposited. Amyloid deposition in superficial dermis produces shiny waxy translucent papules, and common sites of predilection are eyelids, retroauricular areas, neck, and axillae. Amyloid deposits in the deep reticular dermis and subcutis produce nodules and tumefactions. Amyloid infiltration of blood vessel walls produces capillary wall fragility leading to purpura clinically. Periorbital area is the most common site of purpura and may be demonstrable by pinching the skin . Ref - Harrison's internal medicine 20e topic Amyloidosis