Seborrhoeic keratoses are often confused with warts or moles, but they are quite different. Seborrhoeic keratoses are non-cancerous growths of the outer layer of skin. There may be just one growth or many which occur in clusters. They are usually brown, but can vary in colour from light tan to black and range in size from a fraction of an inch in diameter to larger than a £2 coin. A main feature of Seborrhoeic keratoses is their waxy, “pasted-on” or “stuck-on” appearance. They sometimes look like a dab of warm brown candle wax that has dropped onto the skin or like barnacles attached to the skin.

Causes of Seborrhoeic Keratoses

The exact cause of seborrheic keratoses is unknown; however, they seem to run in families. They are not caused by sunlight and can be found on both sun-exposed and non-exposed areas. Seborrhoeic keratoses are more common and numerous with advancing age. Although seborrheic keratoses may first appear in one spot and seem to spread to another, they are not contagious.

Development of Seborrhoeic Keratoses

Anyone may develop seborrhoeic keratoses. Some people develop many over time, while others develop only a few. As people age, they may simply develop more.

Facts about Seborrhoeic keratoses

Seborrhoeic keratoses are most often located on the chest or back, although they also can be found on the scalp, face, neck, or almost anywhere on the body. The growths usually begin one at a time as small, rough, itchy bumps which eventually thicken and develop a warty surface.

Seborrhoeic keratoses are benign (non-cancerous) and are NOT serious and are not generally treated by a dermatologist in secondary care, you can speak with your GP who can offer you the treatment. Removal may be recommended if they become large, irritated, itch, or bleed easily.


Creams, ointments, or other medication can neither cure nor prevent seborrheic keratoses. Most often seborrhoeic keratoses are removed by cryosurgery, curettage, or electro surgery.


Liquid nitrogen, a very cold liquid gas, is applied to the growth with a cotton swab or spray gun to “freeze” it. A blister may form under the growth which dries into a scab-like crust. The keratosis usually falls off within a few weeks. Occasionally, there will be a small dark or light spot that usually fades over time.


The keratosis is scraped from the skin. An injection or spray is first used to anaesthetise (numb) the area before the growth is removed (curetted). No stitches are necessary, and the minimal bleeding can be controlled by simply applying pressure or the application of a blood-clotting chemical.

Electro surgery

The growth is anaesthetised (numbed) and an electric current is used to burn the growth, which is then scraped off.

If you are at all concerned about the area of skin, or see any changes, please contact your GP or Practice Nurse.

Reference: 15-17-105
Review: 11/19