Seborrheic keratosis is one of the most common types of noncancerous (benign) skin growths in older adults. In fact, most people develop at least one seborrheic keratosis at some point in their lives.
A seborrheic keratosis usually appears as a brown, black or pale growth on the face, chest, shoulders and back. The growth has a waxy, scaly, slightly elevated appearance. Occasionally, it appears singly, but multiple growths are more common. Typically, seborrheic keratoses don't become cancerous, but they can look like skin cancer.
These skin growths are normally painless and require no treatment. You may decide, however, to have them removed if they become irritated by clothing or for cosmetic reasons.
The exact cause of seborrheic keratoses is unclear. They tend to run in some families, so genetics may play a role. Ultraviolet (UV) light may also play a role in their development since they are common on sun-exposed areas, such as the back, arms, face and neck.
A seborrheic keratosis usually has the appearance of a waxy or wart-like growth. It typically appears on the head, neck or trunk of the body. A seborrheic keratosis :
- Ranges in color from light tan to black
- Is round- to oval-shaped
- Has a characteristic "pasted on" look
- Is flat or slightly elevated with a scaly surface
- Ranges in size from very small to more than 1 inch (2.5 centimeters) across
- May itch
|You may develop a single growth or cluster of growths. Though not painful, seborrheic keratoses may prove bothersome depending on their size and location. Be careful not to rub, scratch or pick them. This can lead to inflammation, bleeding and infection.
Your doctor can diagnose seborrheic keratosis by inspecting the growth. To confirm the diagnosis or to rule out other skin conditions, your doctor may recommend removal for examination under a microscope.
Typically, seborrheic keratosis doesn't become cancerous, but it can resemble skin cancer. If your doctor suspects skin cancer, he or she will take a small sample of your skin (biopsy) for analysis in a lab. A biopsy can usually be done in a doctor's office using local anesthesia.
Treatment of seborrheic keratoses usually isn't necessary. However, you may want them removed if they become irritated, if they bleed because your clothing rubs against them, or if you simply don't like how they look or feel.
This type of growth is never deeply rooted, so removal is usually simple and not likely to leave scars. Your doctor can remove seborrheic keratoses using several methods, including :
- Freezing with liquid nitrogen (cryosurgery). Cryosurgery can be an effective way to remove seborrheic keratosis. However, it may not work on large, thick growths, and it may lighten the treated skin (hypopigmentation).
- Scraping the skin's surface with a special instrument (curettage). Sometimes curettage is used along with cryosurgery to treat thinner or flat growths. It may be used with electrocautery.
- Burning with an electric current (electrocautery). Used alone or with curettage, electrocautery can be effective in removing seborrheic keratosis. This procedure can leave scars if it's not done properly, and it may take longer than other removal methods.
Keep in mind that most insurance companies and Medicare won't pay for the removal of seborrheic keratoses if done only for cosmetic reasons. Medical reasons for seborrheic keratosis treatment include intense itching, pain, inflammation, bleeding and infection.