"Pinch" purpura is diagnostic of -
Pinch Purpura: A Cutaneous. Manifestation of Systemic. Amyloidosis Amyloid purpura is a condition marked by bleeding under the skin (purpura) in some individuals with amyloidosis. Its cause is unknown, but coagulation defects caused by amyloid are thought to contribute presentation: Amyloid purpura usually occurs above the nipple-line and is found in the webbing of the neck and in the face and eyelids Ref Harrison20th edition pg 1245
Systemic primary amyloidosis
Secondary systemic amyloidosis
Idiopathic thrombocytopenic purpura
Drug induced purpura
Autoimmune skin disorders