What Is Seborrheic Keratosis?
Seborrheic keratosis (a more severe form is known as actinic keratoses) is a small, thickened, scaly growth which develops on the skin, usually on the ears, head, neck, forearms and hands. Seborrheic keratosis is the most common skin condition resulting from excessive exposure to ultraviolet (UV) rays from the sun. Risk is increased by artificial UV radiation such as UVB and PUVA used to treat psoriasis and other skin conditions, as well as from tanning beds. The incidence increases between 45 and 60 years of age. Genetic factors play a role and individuals with fair skin, blue eyes and blonde hair are at higher risk. Usually they are harmless but there is a small risk that they may eventually turn into skin cancer.
What does seborrheic keratosis look like?
A rough and sometimes raised, scaly skin lesion, ranging from the size of a pinhead to 2-3 cm across. Often it is easier to feel rather than see them, especially on lighter skin. Seborrheic keratoses feel rough and dry, and are slightly raised from the surface of the skin. They can also be hard and warty. Their color can be light, dark, pink, red, the same color as your skin, or a combination of these. The top of each one may have a yellow-white, scaly crust. Redness may develop in the surrounding skin. Sometimes hard skin grows out of seborrheic keratosis like a horn (called a cutaneous horn).
Several solar keratoses may develop at about the same time, often in the same area of skin. Sometimes they can join together and form a large, flat-ish, rough area of skin.
Where do they develop?
Seborrheic keratoses usually develop on areas of skin which have received a lot of sun exposure. Skin on the face, neck, ears, bald patches on the scalp and the backs of the hands is commonly affected. They may also appear in other areas (such as the back, chest and legs) in people who do a lot of sunbathing. There are usually no other symptoms. Rarely, you may get an itchy or prickling sensation from affected areas of skin.
Who gets seborrheic keratoses?
Anyone who has been exposed to excessive UV light over many years, especially those who did not use sunscreen or otherwise protect their skin. The skin is normally good at repairing any minor damage, however, over time some areas are unable to cope with the repeated exposure to sun and a solar keratosis can form. Basically, it is not a recent bout of sun-tanning that causes them but repeated minor sun damage to the skin over time.
People with fair skin who do not tan easily are most commonly affected, especially those with blue/green eyes and blonde/red hair. Because their skin has less protective pigment (or melanin), these people are the most susceptible to sunburn and other forms of sun damage. Seborrheic keratoses can occur in people with darker skin, but they are almost unheard of in black-skinned people.
As it usually takes years of sun exposure to develop seborrheic keratosis, so older people tend to be most commonly affected. They may appear at a much earlier age in people who work outdoors (such as construction workers, farmers etc), or those who do a lot of sunbathing or use tanning beds frequently. They are more common in men, mainly because men are more likely to have outdoor occupations.
Seborrheic keratoses are more common in people who have a suppressed immune system, such as people who have had organ transplants (because they take long-term anti-rejection medication), people who have had chemotherapy to treat cancer and people with HIV infection. However, even in such people, they do not occur without exposure of the skin to the sun.
What happens to seborrheic keratoses?
Three things can happen to a seborrheic keratosis. This is important when considering treatment:
The seborrheic keratosis may regress. This means it clears away on its own, without treatment.
Seborrheic keratosis may persist. So, it remains, doesn't change but doesn't disappear either.
Is seborrheic keratosis dangerous?
In themselves, seborrheic keratoses are not cancerous and do no harm. But, they can sometimes be unsightly. Up to about a quarter of seborrheic keratoses cases will clear away by themselves without any treatment over the course of one year.
However, in people who have between seven and eight seborrheic keratoses on their skin, there is about a 1 in 10 chance that one will turn into a form of skin cancer called squamous cell carcinoma (SCC) over a 10-year period. This is not the most serious form of skin cancer (melanoma). It is a fairly slow-growing cancer and can usually be easily cured if treated early enough. This means that seborrheic keratosis can be seen as a potentially premalignant condition of the skin (a precursor to cancer).
Some seborrheic keratoses become cancerous because the UV exposure from the sun's rays causes changes (mutations) in the genes on the DNA of skin cells. This causes skin cells to divide and grow abnormally, instead of just repairing damage. The abnormal cells tend to multiply in an out of control way - this causes a tumor (lump).
How is seborrheic keratosis diagnosed?
Dr. Gillaspie is usually able to diagnose a seborrheic keratosis by its typical appearance alone. Sometimes this is difficult and, if doubt exists, you may examined more closely, perhaps with a dermatoscope. Dr. has extensive advanced training in dermoscopy through the American Dermoscopy Association. This is a magnifier with a light that helps to distinguish between benign (harmless) skin lesions and malignant (cancerous) ones. If it’s it is necessary to take a biopsy of the skin lesion you will be referred to a dermatologist. This means that a small sample of skin is taken and examined under the microscope in a laboratory. A biopsy means that the cells in the skin can be seen and an accurate diagnosis can be given.
What is the treatment for seborrheic keratoses?
Most dermatologists will prescribe a topical treatment such as an emollient cream (moisturizer), gel (water based) or ointment (greasier). These may help soften the skin around the solar keratosis, but may take a lot of time to show improvement, and are sometimes inconvenient as they must be applied several times per day for months at a time. They are usually inexpensive and covered by insurance, however, unwanted side-effects may occur, as with the following common medications:
A gel containing an anti-inflammatory medicine called diclofenac (brand name Solaraze®). Usually at least three months of treatment is needed. Side-effects may include itching and a rash.
A cream called fluorouracil (brand name Efudix®). This kills the abnormal cells and fresh normal skin grows back. This cream is usually applied for 3-4 weeks but it can cause significant (but temporary) inflammation, soreness and blistering of surrounding skin. Fluorouracil cream is often used if someone has a large number of solar keratoses.
Imiquimod cream (brand name Aldara®) is an alternative. It is usually applied three times per week for a month initially. After a four-week break, the response of the skin treated is reassessed. Sometimes it is necessary to repeat one further four-week course. Imiquimod may also cause inflammation, irritation or redness of the skin where it is applied.
Salicylic acid ointment is another cream that is sometimes used. It may be used alone or as a pre-treatment before fluorouracil.
A seborrheic keratosis may be cut or scraped off (shaved biopsy). This are usually done after numbing the skin with some local anesthetic.
Freezing the seborrheic keratoses, using liquid nitrogen, is another common treatment, referred to as cryotherapy or cryosurgery. Liquid nitrogen is so cold that it destroys tissue, which often causes the surrounding skin to blister and scab, leaving a white spot on the skin after treatment.
What Treatment Is Used By Dr. Gillaspie?
Dr. Gillaspie uses the CryoProbe, which is a unique, precision instrument that delivers a fine, pin-point spray of pressurized liquid nitrous oxide. This non-toxic combination of freezing temperature and pressurization helps remove superficial lesions without cutting, bleeding, the need for sutures, or scarring. The treatment is cost effective and usually only one treatment is necessary. If more than one treatment is needed you will be advised before hand. Skin tones will be evaluated and you will be advised as to whether it’s the treatment for you or not. Keloids, inject with a kenalog. Ultrazeal powder is prescribed in order to make sure a scab does not form so the scar, if any, is minimal. You will not end up with a shinny red mark, as with other treatments.
Can seborrheic keratoses be prevented?
If you spend a lot of time in the sun you have an increased risk of developing seborrheic keratoses and skin cancer. You will also prematurely age your skin and cause wrinkles.
To reduce the risk of developing skin cancers, solar keratoses and other conditions associated with sun-damaged skin, we should all:
Stay out of strong sunlight. In particular, avoid sun between 11 am and 3 pm.
When out in the sun:
Seek natural shade in the form of trees or other shelter.
Wear clothes as a sunscreen, including T-shirts, long-sleeved shirts, and hats.
Use a broad-spectrum sunscreen with an SPF of 30 or higher to protect against UVB and UVA.
Reapply sunscreen regularly, particularly if you are swimming, sweating a lot or after toweling yourself dry.
Use plenty of sunscreen. At the very least, six full teaspoons are needed to cover the body of an average adult.
It helps to examine your skin regularly. See Dr. Gillaspie about any skin rashes, growths, lumps or bumps that do not heal within six weeks.