Sebaceous cysts are common, slow-growing lumps that form just beneath the skin’s surface. They typically appear as round or dome-shaped bumps, ranging from a quarter-inch to over two inches. While usually painless and benign, their presence can cause concern or discomfort, making it helpful to understand when medical attention is beneficial.
Understanding Sebaceous Cysts
What are commonly called sebaceous cysts are usually epidermoid cysts. The term “sebaceous cyst” is often a misnomer, as true sebaceous cysts are rare. Epidermoid cysts form when surface skin cells move deeper into the skin instead of shedding. These cells then create the cyst wall and secrete keratin, a protein, into the sac.
The material inside an epidermoid cyst is often a thick, cheesy, and sometimes foul-smelling substance composed of keratin and dead skin cells. These cysts frequently appear on areas with more hair, such as the face, neck, scalp, trunk, and back, but can occur almost anywhere on the body. Unlike fatty lumps called lipomas, epidermoid cysts often have a central dark punctum, a tiny hole or pit, and are typically movable under the skin.
Natural Resolution and Persistence
While small, uninfected epidermoid cysts might occasionally shrink or rupture, they rarely disappear entirely without intervention. The cyst wall typically remains even after the contents drain. If this sac lining is not completely removed, the cyst can refill with keratin and recur.
Factors influencing a cyst’s persistence include its size and whether it becomes inflamed or infected. Larger cysts are less likely to resolve spontaneously and may continue to grow. Cysts that rupture internally or become inflamed often lead to a foreign body reaction, which can result in pain and swelling, but the underlying sac usually remains intact. Most epidermoid cysts, once formed, remain present for years and may increase in size.
When to Seek Medical Care
Individuals should consider seeking medical evaluation for a sebaceous cyst if they observe certain changes or symptoms. A healthcare professional should examine any new lumps or growths on the body to ensure an accurate diagnosis and rule out other conditions, including rare instances of skin cancer. Specific warning signs indicating a need for medical attention include rapid growth of the cyst or an increase in its diameter to over 5 centimeters.
Pain, tenderness, redness, or warmth around the cyst can indicate inflammation or infection. Discharge of pus or foul-smelling, grayish-white material from the cyst signals a potential infection or rupture. If the cyst interferes with daily activities due to its size or location, or causes cosmetic concerns, medical consultation is advisable. Avoid attempting to squeeze, pop, or drain the cyst at home, as this can lead to infection, scarring, and increased recurrence.
Available Treatment Approaches
When an epidermoid cyst does not resolve naturally or becomes problematic, various medical interventions are available. The most definitive treatment for preventing recurrence is complete surgical excision. This procedure is typically performed under local anesthesia and is highly effective when the cyst wall is fully extracted.
For acutely inflamed or infected cysts, a healthcare provider might first perform an incision and drainage to release contents, alleviating pain and swelling. However, if the cyst wall is not removed, refilling and recurrence are likely. In some cases of inflammation, a steroid injection can reduce swelling before potential removal. Laser removal offers a minimally invasive option for some cysts, particularly for cosmetic reasons or in sensitive areas, aiming for less scarring. Antibiotics may be prescribed for bacterial infections, often prior to or with drainage.