Sebaceous cysts most often arise from swollen hair follicles. Skin trauma can also induce a cyst to form. A sac of cells is created into which a protein called keratin is secreted.

These cysts are usually found on the face, neck, and trunk. They are usually slow- growing, painless, freely movable lumps beneath the skin. Occasionally, however, a cyst will become inflamed and tender.

• usually a nontender, small lump beneath the skin
• redness, tenderness, or increased temperature of the skin over the area may occur infection
• grayish white, cheesy, foul smelling material may drain from the cyst

In most cases, your physician can diagnose a cyst based on its appearance. Occasionally, a biopsy may be needed to rule out other conditions with a similar appearance.

Sebaceous cysts are not dangerous and can usually be ignored. At times, they may become inflamed and tender. Others may grow large and interfere with day-to-day life. In these cases, you can have them surgically removed in a physician's office. Alternatively, small inflamed cysts can be treated by injection of steroid medications.