epidermoid cyst vs sebaceous cyst

2 min read 11-03-2025

Epidermoid cysts and sebaceous cysts are common skin lumps that can cause confusion due to their similarities. While both are benign (non-cancerous) and filled with keratinous material, there are key differences in their formation and contents. Understanding these distinctions is crucial for proper diagnosis and treatment.

What is an Epidermoid Cyst?

An epidermoid cyst, also known as an epidermal inclusion cyst, develops from trapped epithelial cells during skin injury or follicle blockage. These cells continue to grow and produce keratin, a tough, fibrous protein that makes up the outer layer of skin. This keratin accumulates, forming a fluid-filled sac beneath the skin's surface.

Characteristics of Epidermoid Cysts:

Appearance: Usually small, round, and dome-shaped. They can range in size from a pea to a few centimeters.
Texture: Firm to the touch, often feeling smooth.
Color: Often skin-colored, but can sometimes appear slightly reddish or yellowish.
Location: Common on the face, neck, back, and scalp.
Contents: Filled with a thick, cheesy, white or yellowish material (keratin). The cyst wall itself is often quite thin.
Pain: Usually painless unless infected or inflamed.

What is a Sebaceous Cyst?

A sebaceous cyst, or epidermoid cyst, arises from a blocked sebaceous gland. Sebaceous glands produce sebum, an oily substance that lubricates the skin. Blockage prevents the sebum from draining, leading to the formation of a cyst. While often called a sebaceous cyst, it’s important to note that its contents are primarily keratin, not sebum.

Characteristics of Sebaceous Cysts:

Appearance: Can vary in size, from small to several centimeters in diameter. They can be round or irregular in shape.
Texture: Often feels softer and more fluctuant (meaning it moves slightly when pressed) than an epidermoid cyst.
Color: Usually skin-colored, but may appear reddish if inflamed.
Location: Can appear anywhere on the body where sebaceous glands are found.
Contents: Mostly keratin, although it might appear more yellowish or greasy than the contents of an epidermoid cyst.
Pain: Typically painless, unless infected.

Key Differences Between Epidermoid and Sebaceous Cysts:

Feature	Epidermoid Cyst	Sebaceous Cyst
Origin	Trapped epithelial cells	Blocked sebaceous gland
Contents	Primarily keratin, thick, cheesy, white/yellow	Primarily keratin, potentially more yellowish/greasy
Consistency	Firm, less fluctuant	Softer, more fluctuant
Wall Thickness	Relatively thin	Often thicker

When to See a Doctor:

While both cysts are generally benign, it's important to see a dermatologist or healthcare professional if:

The cyst becomes infected: Signs of infection include increased pain, redness, swelling, and warmth around the cyst.
The cyst grows rapidly or changes in appearance: Significant changes warrant a professional evaluation to rule out other conditions.
You experience significant discomfort: Even if not infected, a large or painful cyst may require medical attention.

Treatment Options:

Treatment options depend on several factors including size, location, and the presence of infection. Options often include:

Observation: Small, asymptomatic cysts may not require treatment.
Incision and Drainage: The cyst is opened to drain the contents. This may not be curative, and recurrence is possible.
Surgical Excision: The entire cyst, including its capsule, is surgically removed. This is the most effective method for preventing recurrence.

Disclaimer: This information is for educational purposes only and should not be considered medical advice. Always consult with a healthcare professional for diagnosis and treatment of any skin condition.