What is Seborrheic Keratosis?

By Cristiano Antonino On Mar 30, 2023

In the medical field, seborrheic keratosis or seborrheic wart is a form of benign tumor of the epidermis that appears as a usually round or oval, flesh-colored, brown or black spot

It often develops in a verrucoid form, but can sometimes also present as a smooth papule.

These completely harmless growths are often common in middle-aged and older people.

Although not dangerous, seborrheic keratosis can be confused with other skin diseases

These could instead lead to carcinogenic forms if not treated promptly.

For this reason it is always important to rely on a dermatologist to have a correct diagnosis and understand if treatment is necessary.

Seborrheic keratoses or seborrheic warts are usually defined as round or oval-shaped growths with an almost always waxy, verrucous, scaly and crusty surface that develop on the skin surface.

This type of growth can vary both in color, ranging from light brown to brown to black, and in size, which generally ranges from minus 0.5 cm to several centimeters.

Dark brown keratoses can sometimes be mistaken for melanomas or atypical moles.

Generally these pigmented lesions develop slowly and gradually in predisposed subjects.

However, in some patients with paraneoplastic skin syndrome or those with certain types of cancer, such as lymphoma or tumors of the gastrointestinal tract, they can develop very rapidly and be extensive and multiple in size.

Seborrheic keratoses are adherent to the skin, i.e. they appear almost “glued” and can often flake and form crusts prone to detach

They generally occur in people who have reached an advanced average age (40-50 years) and affect both men and women without distinction.

The skin lesion is recorded more frequently in the Caucasian race while it is rare to find it in Orientals and in subjects of the African race.

The causes of the manifestations of seborrheic keratosis are still unknown and being studied

The only correlation that doctors seem to agree on is that of a genetic nature.

The most accredited hypothesis to date is in fact the one that suggests that seborrheic warts can be genetically transmitted in an autosomal dominant manner.

There is also familiarity with regards to the number and location of the growths.

One thing that is certain is that hormonal alterations, although not the triggering cause of seborrheic keratosis, can accelerate its growth and consequently its evolution.

In fact, the moment of high hormonal modulation such as menopause often coincides with the strengthening of the lesions.

Some studies have suggested a link between the development of the disease and radiation from UV rays.

A hypothesis derived from the fact that subjects who have been exposed to the sun for prolonged periods of time tend to develop seborrheic keratosis.

However, since the disorder also occurs in people who have not exposed themselves excessively to the sun’s rays, UV rays do not seem to play an important role.

The debate on the implication of sunlight in the etiology of seborrheic keratosis therefore still remains open.

Clinical manifestations of seborrheic keratosis

Generally, seborrheic keratosis begins to appear as a small yellowish papule: a lesion of the skin raised with respect to the skin plane which appears in relief and is therefore palpable.

Over time it tends to darken and vary in size, enlarging and starting to flake.

Depending on the subtype of seborrheic keratosis afflicting the patient, the color of the lesion can vary significantly.

As anticipated, the lesions can vary considerably in size and, even if in most cases they present with a reduced size, cases have been recorded in which the papules reached a considerable diameter (4-5 cm).

It may happen that you notice a kind of “detachment” in the lesion, to the point that it seems that the seborrheic keratosis is just attached to the skin and is easy to detach.

In fact, it is not uncommon that, following a trauma, the growths detach partially or completely, precisely because of the precariousness with which they are attached to the skin.

Although seborrheic keratoses look a lot like warts to the point of being called “seborrheic warts”, it is important to point out that these formations are in no way contagious and totally benign in nature.

Subtypes of seborrheic keratosis

As mentioned above, we are now going to illustrate the various subtypes of seborrheic keratosis that have been identified up to now:

Acanthotic seborrheic keratosis: considered the most frequent form. The pigmentation varies from hazelnut to dark brown and the formations present horny pseudo-cysts which tend to take on a yellowish colour.
Acroposta seborrheic keratosis or stucco keratosis: the skin lesions are multiple and develop in most cases on the lower limbs.
Hyperkeratotic seborrheic keratosis: presents keratotic manifestations that tend to flake off continuously.
Pigmented seborrheic keratosis or melanoacanthoma: the keratotic manifestation presents itself with multiple pigmentations.
Irritated seborrheic keratosis: Also called inverted, the skin lesion is accompanied by skin changes or irritation. The skin around the area may be bloody and red. The infiltration of melanophages in the irritated areas can give the seborrheic formations a bluish colour, causing some diagnostic doubts.
Dermatosis papulosa nigra: this type of dermatological disease affects subjects with a high phototype and manifests itself with multiple small hyperpigmented spots especially in the area around the cheekbones. However, it should be noted that it is not yet clear whether this disease can be considered a variant of seborrheic ceratosis.

Diagnosis

For a correct diagnosis it is advisable to consult a dermatologist who will be able to correctly evaluate the disorder by carrying out an analysis of each individual seborrheic keratosis and excluding any other skin diseases.

In fact, it is necessary to perform a differential diagnosis excluding other much more serious skin diseases that have similarities with seborrheic warts.

Among these we mention:

Plane melanoma in plaque
Solar lentigos
Squamous cell carcinoma
Pigmented basal cell carcinoma
Pigmented actinic keratosis

The useful test for a correct diagnosis and a differential analysis to distinguish seborrheic keratosis from much more serious diseases that afflict the skin is dermatoscopy.

Also known as epiluminescence, this innovative diagnostic technique allows you to recognize in advance any melanoma and melanocytic skin lesions, whether they are pigmented or not.

This type of analysis is absolutely non-invasive and is performed using an instrument called an optical dermatoscope.

Once he has made sure that the diagnosis of both seborrheic keratosis is correct, the doctor will be able to identify the subtype of superficial epithelial lesion that afflicts the patient and together with it establish the need to intervene on it or not.

Possible types of treatment

Since seborrheic warts are benign growths, and therefore never turn into cancerous lesions, they do not require any type of treatment (if not of an aesthetic nature) especially if they remain asymptomatic and do not cause discomfort to the patient.

In some cases, however, seborrheic keratoses can become irritated, inflamed and itchy or have unregulated and excessive growth.

In situations like these, these lesions could not only cause functional discomfort to the subject, but also have serious repercussions on an aesthetic level.

In these cases, the removal of the seborrheic keratoses can be resorted to

The patient, in agreement with the dermatologist, can resort to one of the following treatments to remove the lesion.

Diathermocoagulation (or electrocoagulation): dermatological technique used to remove small portions of epidermal tissue;
Cryotherapy: literally “cure with cold”, it is a method of treatment that has gained ground in recent years. The therapy consists in the application of liquid nitrogen on the area afflicted by the skin lesion which will lead to a freeze burn and the consequent fall of the seborrheic keratosis;
Laser: considered among the optimal treatments for the removal of seborrheic warts. Through the use of CO2 laser or Erbium laser it is possible to carry out an accurate vaporization of the lesion, saving the healthy skin around it and having a complete healing without scarring;
Curettage: a procedure that removes superficial skin lesions using a special cutting instrument called a curette. The treatment is easy to perform and allows for an excellent aesthetic result, effectively removing benign neoformations such as seborrheic keratosis.
Electrocautery: an effective technique which, however, must be performed by extremely experienced personnel as it can lead to the formation of residual scars.
Whatever type of treatment chosen the removal of the lesion will be permanent so the seborrheic keratosis will never appear again in the area from which it was removed.

However, the appearance of new seborrheic warts in areas other than those treated cannot be excluded.

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