A Janeway lesion is a dark spot, usually circular, that occurs on the soles of the foot. It may also appear on the palms of the hands. Upon close examination, you will see an abscess in the area of the Janeway lesion. A Janeway lesion is not painful. Cause A Janeway Lesion is caused the a blood clot that causes sepsis. It is usually associated with the toxin of Staphylococcus aureus, which causes inflammation of the inner lining of the heart. Treatment and Prevention Treatment involves medication for the Staphylococcus infection, which is especially important to prevent the damage to the heart and damage to the body wherever the emboli disrupt oxygen flow to the body. Not having enough oxygen to the body can cause dying tissue, which will cause additional problems and possibly even the loss of a limb. Developing a Staphylococcus infection in the first place generally means that the individual is immune-compromised. Thus, it’s important to correct any deficiencies in the immune system, which are frequently due to faulty nutrition – not enough protein in the diet, zinc deficiency, selenium deficiency, vitamin A and vitamin C deficiency.