Venous lakes are small, dark blue to purple spots that commonly appear on the lips, face, back, neck and ears. They are soft and compressible, and are typically asymptomatic, causing no pain or symptoms. Venous lakes are made up of abnormally dilated veins. No one knows what causes venous lakes to appear, but sun and UV damage are thought to play a role.

Venous Lakes are usually harmless and do not pose any health risks. They may rupture if they are damaged or subjected to trauma. Scratching or bumping a venous lake may cause it to bleed from bursting the blood vessels inside the lesion. Sometimes this bleeding can be hard to stop and may requiring applying pressure for an extended amount of time. In rare, extreme cases, some people must seek medical attention to have the venous lake cauterized to stop the bleeding.

For benign vascular lesion treatments, such as venous lakes and cherry angiomas, the laser light is absorbed by hemoglobin in the veins, and the heat produced causes photocoagulation (clotting of blood). Heat is transferred to the vessel wall, which ultimately destroys the vessels and prevents recanalization. This prompts the body to resorb and heal the vessels in the venous lake, which allows the venous lake to fade away gradually.