Amyloidosis

The purpura on the eyelids of this 81-year-old woman proved to be caused by amyloidosis.

A tissue biopsy confirmed the presence of amyloid, a proteinaceous material that stains pink with Congo red stain. Amyloid deposition weakens the vessel walls and leads ultimately to extravasation of red blood cells, which is visible as purpura. So-called pinch purpura is thought to affect eyelids more often because of their accessibility, extremely thin dermis, and high susceptibility to trauma. It can occur in patients with a history of little or no trauma.

The process of amyloid deposition can be primary or secondary; the latter often is caused by multiple myeloma, as was the case in this patient.

The differential diagnosis of pinch purpura includes trauma, thrombocytopenia, vasculitis, and iatrogenic purpura (eg, secondary to warfarin). ■