Sinonimi: Seborrhoic keratosisSenile keratosisBasal cell papillomaKeratosis

What is SK?

It’s a benign tumor of the superficial layer of the skin. It usually looks as a dried up crust, or like something glued to the skin

Solitary SK lesion

SK lesions in group

How does SK develop?

We still don’t fully understand the true reason for developing this tumor. Still, genetic predisposition and excessive skin Sun damage during life present the two main reasons for developing SK.

What are the first signs of developing SK?

Fundamentally, there are two types of occurring SK, solitary and group type. With solitary lesion type, they are spotted as small lesions (up to 10 mm) in the form of wart-like, mole-like or elevated growths with a dry surface. When they appear in groups, they initially look like “small warts” and are usually located on the neck, and when they appear on the back, chest or trunk, they are usually dry, oily lesions, like soft “limpets” that crumble.

Small, wart, mole-like or elevated growths

Dry, oily lesions, like soft, crumbling “limpets”.

How do they look like?

  • They clearly demarked from the surrounding tissue,
  • Brown to black in color,
  • Elevated, like attached to the skin,
  • Soft and crumbly,
  • Often with darker “plug like spots” on them,
  • They tend to partially crumble, especially after a bath,
  • Often, these are lesions from a couple of cm in diameter, rarely they are up to a few cm in diameter.
  • Crusts appear usually on lesions that have been injured or inflamed.
  • Rarely, these can be lesions on a petal, and if they do appear, it’s mostly on the neck or upper part of the chest .

How dangerous are they?

SK lesions are harmless benign skin tumors. They only pose issues with itching, discomfort, loss of life comfort and, of course, with esthetics. However, in a small number of cases, regular SK lesions can’t always be separated from melanoma by a common visual examination. And exactly because of that, a dermoscopic examination which provides a precise diagnosis should be done on SK lesions before removing them.

Is it curable?

Like with all benign lesions, the cure is complete. It should be known that they can appear again on the same spot, if not completely removed, as well as on other, new spots, near or far away especially when the type in question is the group one.

Is there a sex, age or body region specificity?

SK lesions appear in both sexes equally. Age-wise, for a long time the prevailing opinion was that these are old age related lesions, and theat they don’t appear before the age of 30. Unfortunately, more and more cases of SK appearing before the age of 20are reported. They usually appear on the chest, back and face.

SK risk factors and preventive measures

There are no specific risk factors for developing SK lesions. Anyone can get an SK lesion but the chances are greater for:

  • Persons whose parent has had a history of SK lesions and
  • Persons who have had excessive Sun exposure or have used sunbeds for tanning before the age of 20.

There are no specific measures of prevention. Only preventive measures that could be of use, especially on persons that have a familial inclination for developing SK, are the basic sun protection measures.


Diagnosis of SK lesions is acquired by: clinical examination, dermoscopy and, of course biopsy.

In all possible cases, dermoscopy is the method of choice before removing, and histopathological analysis is obligatory after removing. Use of biopsy as a diagnostic method before a complete removal can be used only in extreme cases, when a clinical examination can’t give a definitive answer and there is no possibility of dermoscopic diagnostics.

Clinical appearance


Clinical appearance


How is it treated?

The basic method of treating SK lesions is removal with a histopathological analysis.

SK lesions are removed in one of the following ways:

  • Classic surgical techniques
    • Curettage
    • Excision
  • Other surgical techniques
    • Radiofrequency surgery
    • Laser surgery
    • Cryosurgery



Radiofrequency surgery – layered removal

All of these procedures are done under local anesthesia.

Frequently asked questions

Is it contagious?

SK lesions are not contagious.

A certain part of our population, especially older women, has a fear that crust like skin lesions can be contagious.

How many skin lesions can be removed in a single intervention?

In a single intervention, under local anesthesia, up to 50, even a 100 SK lesions can be removed.

How many days off work?

Maximally, there is a need for 1 day off work, if only 1 or a just few lesions were removed, and up to 3 days when a large number of SK lesions is removed.

Is there some special care requirement after removing SK lesions?

No specific care is necessary. Keeping the area where the lesions were removed clean is most important. You will receive specific and precise instructions for care and treatment after removal, and they depend on the technique used for removal.