Medically reviewed by Dr. A.M. van Coevorden, dermatologist
Seborrheic keratosisharmless, rough wart-like growths that increase with age
Seborrheic keratosis, in everyday terms senile warts, are harmless, wart-like growths on the skin that are very common. Their number increases with age, although younger people can get them too. They are not malignant and cannot lead to cancer, but are sometimes confused with other spots.
What are seborrheic keratoses?
Seborrheic keratoses are benign wart-like patches on the skin that are very common. The number increases with age, but younger people can develop them too. The medical name is verruca seborrhoica.
What do they look like?
They are often round to elongated patches with an almost always rough surface, whose rough top layer sometimes crumbles. The colour is often yellowish, greyish or light brown, sometimes dark brown to black, usually dull. They grow from a few millimetres to a few centimetres and appear mainly on the trunk and temples, but can occur anywhere, from a few to hundreds. In folds, such as under the breasts or in the armpits, they can sit in rows. There are variants, such as dermatosis papulosa nigra (small dark bumps, mainly on dark skin), stucco keratosis (small white-grey hard spots on the lower legs) and a flat wart-like form on the backs of the hands and forearms.
How do you get them?
The cause is not fully known. Heredity and a lot of sun exposure probably play a role.
What symptoms do they cause?
Seborrheic keratoses usually cause no symptoms, although they can sometimes itch. They occur most often on the trunk, arms and face.
Are they contagious?
No. Seborrheic keratoses are not contagious.
What treatments are there?
Because they are benign, seborrheic keratoses do not need to be removed. If you do want that, for cosmetic reasons, because they are in the way or itch, there are several techniques. Scraping with a sharp spoon leaves a superficial graze that heals with a crust. Freezing with liquid nitrogen makes the growth die off and fall away. Electrocoagulation dabs and burns off small growths, preferably after anaesthetic. Large, protruding growths can be cut off under local anaesthetic with a blade.
Can they cause cancer?
No. Seborrheic keratoses are not malignant and cannot lead to cancer. If you are unsure whether a spot is a seborrheic keratosis or something else, have it assessed by a doctor.
What can you do yourself?
You cannot influence how they develop or progress. If they bother you, it is wise to see a doctor to have the spot assessed and possibly removed. Scratching them off yourself can cause small wounds that become infected.
What is the outlook?
Seborrheic keratoses do not disappear on their own. Over the years they can grow larger or thicker and sometimes bleed or become irritated.
Frequently asked questions about seborrheic keratoses
Are seborrheic keratoses dangerous?
No, they are benign and cannot lead to cancer. If you are unsure about a spot, have it assessed by a doctor.
Do they need removing?
Not necessarily. Removal is only done if they are in the way, itch or for cosmetic reasons.
How are they removed?
By scraping, freezing, burning off or, for large growths, cutting off under local anaesthetic.
Do they go away on their own?
No. They do not disappear on their own and can grow larger or thicker over the years.
Can I remove them myself?
Better not. Scratching them off can cause wounds that become infected. Leave it to a doctor.