Sebaceous Cyst


Sebaceous cysts, or epidermoid cysts, are slow-growing bumps that can form under the skin in several areas of the body. True sebaceous cysts are rare and are caused by blocked sebaceous glands – glands that produce sebum to lubricate hair and skin. However, the term sebaceous cyst is often used when referring to epidermoid cysts, or small, painless bumps underneath the skin. These cysts are typically harmless, although they can burst and become infected or, in rare cases, lead to skin cancer. If treatment for a cyst is needed, it can be surgically removed.

Symptoms and Diagnosis

Sebaceous cysts (epidermoid cysts) are small, smooth bumps under the skin that are usually painless. These cysts are slow-growing and mobile, which means they can be easily moved when touched. They can occur almost anywhere on the body, but they most commonly form on the face, neck, and trunk. The only places on the body that cannot form cysts are the palms of the hands and the soles of the feet. Since cysts may be caused by blocked hair follicles, they tend to be found in areas of the body with hair. Cysts can contain tissues, keratin (a cheesy, smelly substance), sebum, and pus and blood. Although most cysts are not harmful, they can become infected or rupture and form an abscess. If a cyst becomes infected, it will be red, tender, and warm, and it may have thick, foul-smelling drainage. Cysts in the genital areas may cause discomfort during urination or sex. Rarely, epidermoid cysts may become cancerous. Cysts are diagnosed based on an examination of the skin, although a biopsy can be done to rule out other conditions.


Sebaceous cysts are caused by blocked hair follicles or sebaceous glands. Injury to the skin, such as that caused by acne, can lead to cyst formation by rupturing the sebaceous glands. Hair follicles can become blocked by epidermal (skin) cells when they are damaged by abrasions. Other causes of sebaceous cysts include genetic disorders and developmental defects. Anyone can get sebaceous cysts, but they are more common in men, people who have had acne, and people who get significant sun exposure. Any type of injury the skin raises the risk of developing a cyst. Continue reading for Prevention and Treatment Information . . .

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