Osler Nodes are darkened sores on the pads of the fingers and toes that are painful. They may be felt during palpation of the area that’s affected. Cause Osler’s nodes are caused by an immune system reaction in the body. When the body is bombarded with an infectious agent, then the immune system cells combine with the toxins and form immune complexes. The immune complexes cause pain where they occur. They often are due to Staphylococcus aureus toxin which is associated with endocarditis, an inflammation of the heart. Treatment and Prevention Treatment involves the prescription of medication for the infection first. Once this is taken care of, the Osler nodes will fade away. During the time that the pain is felt, tight shoes should be avoided. A shoe with a wide toe box and/or a high toe box will help alleviate the pain that may be aggravated by tight shoes.