Differences between actinic and seborrheic keratoses

What is Keratosis?

Before we talk about the differences between actinic and seborrheic keratoses, we need to define keratosis in general. This term refers to irregular keratin skin growths that develop out of keratinocyte cells, which are the most common types of skin cells. When these cells overgrow or replicate in atypical ways, it can lead to a number of skin conditions, including actinic and seborrheic keratosis. While these conditions are caused by damage to the same types of skin cells, the resulting conditions, including actinic and seborrheic keratoses, are different.

What is Actinic Keratosis?

Actinic keratosis is a skin condition that causes the growth of rough patches of skin that usually develop on the hands, face, neck, arms, and shoulder. These lesions typically develop in groups. Actinic Keratosis is sometimes called solar keratosis because it most often develops in areas that receive frequent sun exposure. It can take decades for a person to develop actinic keratosis, so most people don’t see these growths until the age of 40 or older. While actinic keratosis is harmless, a small number of these lesions (about 10%) develop into skin cancer, specifically, squamous cell carcinoma, so it’s important to protect your skin and minimize sun exposure, especially after developing actinic keratosis.

Symptoms of Actinic Keratosis

Symptoms of actinic keratosis vary, and it can be difficult to distinguish this condition from more serious skin health issues, so you should visit a dermatologist to receive an accurate diagnosis. Some of the common symptoms experienced by individuals who develop actinic keratosis include:

Patches of skin may feel scaly, rough, or thickened; these patches are often called plaques

Usually, clusters of plaques develop in the same area

Lesions may be more difficult to see, but they vary in shade from skin-colored, yellow, brown, and black to blotchy or inconsistent coloring

Plaques are adherent, meaning they don’t move easily, and they are flat or slightly raised off the skin

May develop bumpy or wart-like texture overtime

In rare cases, affected areas may be sensitive, burn, itch, or cause other uncomfortable sensations

Lesions may grow and change in color, texture, or shape

Lesions may bleed easily and sores can take longer to heal than is typical

Growths may appear and disappear in the same area

Causes of Actinic Keratosis

The main cause of actinic keratosis is ultraviolet (UV) exposure, which is why this condition is often referred to as solar keratosis. Actinic keratosis usually develops in areas that receive frequent, intense, or prolonged UV exposure to the sun or artificial UV rays like those used in tanning beds. While a sunburn can happen immediately following UV exposure, other forms of sun damage like wrinkles, age spots, and actinic keratoses are caused by years or even decades of accumulated damage. Actinic keratosis is often referred to as a pre-cancer, and when left untreated, these skin lesions can develop into skin cancer.

Risk Factors for Actinic Keratosis

The vast majority of actinic keratosis cases occur when people have long-term exposure to sunlight, especially if they have a light skin tone that is prone to freckling. In addition to pale skin and prolonged sun exposure, other risk factors include:

Age (more common in people over the age of 40)

Gender (more common in men than women)

Outdoor occupation

Living in warm and sunny climates

Have had numerous sunburns

Use (or used) tanning beds regularly

Weakened or suppressed immune function

Past instances of actinic keratoses or skin cancer

How is Actinic Keratosis Treated?

There are numerous options for actinic keratosis treatment, depending on the size and location of the lesions. In most cases, your dermatologist will recommend treatment for actinic keratosis growths because they have a risk of developing into squamous cell carcinoma. Recommended treatment for actinic keratoses may include:

Medication – Oral retinoids can be effective in clearing up widespread actinic keratosis while minimizing the risk of adverse effects like pain, scarring, and the risk of infection.

Topical therapies – 5-fluorouracil cream, 5-aminolevulinic acid, tretinoin, imiquimod cream, ingenol mebutate gel, and diclofenac gel may be applied topically to destroy actinic keratoses lesions. In most cases, this is the recommended course for patients who have lesions covering larger areas of the body. This prevents unnecessary discomfort and reduces the risk of infection during the healing process.

Cryotherapy – This is the process of freezing damaged cells, using liquid nitrogen, to destroy and remove them. This treatment works well for small to medium-sized lesions, but the treatment process can be uncomfortable. Additionally, the side effects of treatment can be uncomfortable, including changes to skin color, blistering, and scars.

Curettage – This is the process of using a specialized dermatological device called a curette to scrape away the damaged tissues.

Electrocautery – Surgery using electrical current to destroy skin cells. May be used after curettage to minimize bleeding and risk of infection.

Photodynamic therapy – A chemical is applied to the skin followed by the application of a specialized light to remove the damaged skin cells.

Laser ablation – Use of laser light rays to destroy and remove the damaged tissues.

Other options – Chemical peels and dermabrasions may also be recommended by your dermatologist to remove actinic keratosis and improve overall skin health and appearance.

Can I Prevent Actinic Keratosis?

Avoiding sun damage is the most important preventive measure for those who are at risk for actinic keratosis. To protect skin from potential sun damage, patients should keep the following in mind:

Limit time exposed to sunlight and avoid tanning beds and other synthetic forms of UVA/B rays

Avoid time outdoors during peak sun exposure hours between 10 am and 4 pm

Apply a broad-spectrum sunscreen with an SPF of 30 or higher every day, including protecting all exposed parts of the face and body as well as the lips

Reapply sunscreen at least every two hours

Wear hats, sunglasses, gloves, and other protective clothing items to block out the sun’s damaging rays

In addition to limiting exposure and protecting skin from sun damage, patients should also check their skin at least once a month for signs of actinic keratosis and skin cancer. By regularly monitoring your skin, you are more likely to notice changes in the early stages when actinic keratoses and skin cancers are more easily treated.

What is Seborrheic Keratosis?

Seborrheic keratosis is a common skin condition that causes noncancerous skin lesions. Seborrheic keratoses often appear on the head, neck, shoulders, chest, and back. Although people of any age can develop seborrheic keratosis, most people who develop this condition are over the age of 50. These skin growths do not pose any threat to general wellbeing or skin health.

Symptoms of Seborrheic Keratosis

Seborrheic keratoses lesions often look wart-like. A single growth may appear, but it is much more common for people to develop a cluster of seborrheic keratoses lesions. They most often form on the face, chest, shoulders, and back. General symptoms of seborrheic keratosis include:

Rough, thickened skin lesions, called plaques, that may be flat or raised

Tan, brown, or black-colored lesions

Can be one or a cluster of lesions

Like actinic keratoses lesions, are adherent and unmoving on the surface of the skin

Lesions look shiny as if they’re pasted onto the skin

Can be itchy, stinging, or easily irritated

May bleed easily

Many skin growths appear quickly, but you should visit a dermatologist right away if growths are changing, growing, or ulcerated

Causes of Seborrheic Keratosis

Unlike actinic keratosis, which is definitively linked to sun exposure, medical professionals are not certain what the specific causes of seborrheic keratoses are. However, the condition tends to be inherited within families, so genetics definitely plays a role.

Risk Factors for Seborrheic Keratosis

Seborrheic keratosis is more common in adults over the age of 50 and for those who have a family history of the condition. While seborrheic keratoses lesions are benign, they have been linked to cancer in the colon, lungs, and other parts of the body. For this reason, it’s important to talk to a medical professional about seborrheic keratosis.

How is Seborrheic Keratosis Treated?

In most cases, we don’t recommend treatment for seborrheic keratoses. The lesions are generally benign, and if they’re not causing any discomfort or other concerns, treatment isn’t necessary. If the appearance bothers patients or the lesions are bleeding, irritated, or inflamed, we can provide several treatment options. Common seborrheic keratosis removal techniques include:

Cryosurgery – Using extreme cold from liquid nitrogen to destroy the damaged skin cells

Curettage – Using a scalpel to remove the growth

Electrocautery – Using electricity to burn away the lesions

Laser ablation – Using laser rays to destroy the growth

Topical therapy – Using a high concentration of hydrogen peroxide to dissolve the damaged skin cells

Can I Prevent Seborrheic Keratosis?

Unfortunately, since this condition is linked closely to natural aging processes and genetics, seborrheic keratosis can’t be prevented. Luckily, the condition is benign and doesn’t cause any significant concerns .