What is the cause of syringoma?

Syringomas are caused by the overproduction of skin cells in the sweat glands. This overproduction causes the sweat glands to become blocked and trapped inside the skin. The trapped sweat then forms a cyst, which is a small, fluid-filled sac. Syringomas are usually benign, meaning that they are not cancerous. However, they can sometimes be itchy or painful.