Osler's nodes are painful, red, raised lesions found typically on the hands and feet.

[1] They are associated with a number of conditions, including infective endocarditis, and are caused by immune complex deposition.

[3] The resulting inflammatory response leads to swelling, redness, and pain that characterize these lesions.

The latter, which also occur on the palms and soles, can be differentiated from Osler's nodes because they are non-tender.

[6][7] He described them as "ephemeral spots of a painful nodular erythema, chiefly in the skin of the hands and feet.