- What Is It?
What Is Seborrheic Keratosis?
Seborrheic keratoses are a common benign skin growth that usually occurs in people over age 50. The growths can have a variety of appearances but are somewhat flat and scaly with a rough texture, and may look like something artificially stuck on the skin. They are usually oval in shape and may be individual or clustered. The lesions are not cancerous. Seborrheic keratosis is the singular; seborrheic keratoses are plural.
What Are Symptoms of Seborrheic Keratosis?
Seborrheic keratoses growth usually does not cause any symptoms. Most of the time they are an annoyance and patients may feel the lesions are unattractive looking. They may be sparse or numerous and commonly appear on the trunk, arms, and face and neck, but can occur on any part of the body.
The lesions may be:
- Light tan, brown, or black in color
- Scaly or waxy in appearance
- Oval in shape
- Seem as if they are stuck on the skin
- Mole-like in appearance
- Generally flat though sometimes have a wart-like texture and appearance
- May have plugged hair follicles
- Dull or lackluster appearance
- Any size from tiny to approximately 3 cm
Sometimes lesions can become bothersome and may:
- Rub or catch on clothing
- Become inflamed
- If they are rubbed on too much or scratched, they may bleed
What Causes Seborrheic Keratosis?
The cause of seborrheic keratoses is unknown but it is thought to have a genetic component.
Risk factors may include:
- Age over 50
- Family history of seborrheic keratoses
- Sun exposure
- People with fair skin
- Hormonal changes in women
- Chronic dermatitis
- Chronic irritation of skin folds
How Is Seborrheic Keratosis Diagnosed?
Seborrheic keratoses are generally diagnosed with a physical exam of the skin. In some cases, tests may be needed to rule out skin cancers.
- A shave biopsy may be needed for an accurate diagnosis. In this procedure, a doctor takes a small sample of the growth and the tissue is examined under the microscope to check for skin cancer.
- A dermoscopy in which a doctor views the skin with a small lighted microscope can also help diagnose if growth is a seborrheic keratosis or something else.
If multiple itchy seborrheic keratoses occur, this is called the Leser-Trélat sign, which is associated with the development of certain cancers, including adenocarcinoma of the gastrointestinal tract, lymphoma, Sézary syndrome, and acute leukemia. Additional tests may be indicated to determine if these conditions are present.
What Is the Treatment for Seborrheic Keratosis?
Most seborrheic keratoses do not cause any symptoms and do not require treatment, however, many people are bothered by their cosmetic appearance and want them removed. The growths should not be scratched off. This does not remove the growths and can lead to bleeding and possible secondary infection.
Seborrheic keratoses can be removed with:
- Cryotherapy – freezing the growth
- Liquid nitrogen
- Carbon dioxide (dry ice)
- A scalpel, laser, or other small tools to remove the tissue
- Shave biopsy
- Excision using a scalpel
- Laser or dermabrasion surgery
- Keratolytic therapy
- Laser ablation
- Electricity to burn away the lesion
- Electrodesiccation and curettage used together has a better rate of successful treatment
- Topical treatments
- Ammonium lactate lotion (AmLactin, Lac Hydrin)
- Trichloroacetic acid (Tri-Chlor)
- Tazarotene cream
- Concentrated hydrogen peroxide 40% solution (Eskata)
What Are Complications of Seborrheic Keratosis?
Seborrheic keratoses can be bothersome and many people may consider them unsightly. In extreme cases, this may cause depression or decreased socialization. Growths may itch and may rub or catch on clothing, becoming inflamed. Excessive rubbing or scratching may cause lesions to bleed, which can result in infection.
Seborrheic keratoses themselves are harmless (benign), but secondary tumors from skin cancers such as squamous cell carcinoma or malignant melanoma may sometimes occur within a seborrheic keratosis lesion. Tell your doctor if you notice any new growths on your skin or any changes in existing growths.