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There are two kinds of keratoses, actinic and seborrheic. Only one of them is associated with a greater skin cancer risk.
Actinic Keratoses are scaly papules that occur on exposed skin of older, fairer-skinned, persons resulting from chronic overexposure to ultraviolet light from the sun.
Although Seborrheic Keratoses are often confused with moles, warts and melanoma skin cancer, they differ in a variety of ways. Seborrheic keratoses are non-cancerous growths of the outer layer of skin.
Causes & Development
Actinic keratoses are especially common in fair-skinned persons or those who have worked outdoors for long periods.
Although the exact cause of seborrheic keratoses is not known, almost everybody will eventually develop at least a few of these growths. They are sometimes referred to as the "barnacles of old age". These become more common and more numerous with advancing age.
Some people develop many over time, while others develop only a few. Sometimes seborrheic keratoses may erupt during pregnancy, following estrogen therapy, or in association with other medical problems.
Signs & Symptoms
Actinic or "Solar" keratoses are mostly found on sites repeatedly exposed to the sun especially the backs of the hands and the face, most often affecting the nose, cheeks, upper lip, temples and forehead.
Seborrheic Keratoses may involve just one growth, or many which occur in clusters. They are usually brown, but can vary in color from light tan to black. They vary in size from a fraction of an inch in diameter to larger than a half-dollar. A main feature of seborrheic keratoses is their waxy, "pasted-on" or "stuck-on" look. They sometimes look like a dab of warm brown candle wax that has dropped onto the skin.
Seborrheic keratoses are most often found on the chest or back, although, they can also be found on the scalp, face, neck, or almost anywhere on the body. They appear less often below the waist. Since they are not caused by sunlight, they can be found on sun-exposed or covered areas. When they first appear, the growths usually begin one at a time as small, rough, itchy bumps. Eventually, they thicken and develop a rough, warty surface.
Children rarely develop seborrheic keratoses. Although seborrheic keratoses may first appear in one spot and seem to spread to another, they are not contagious. As people age they may simply develop a few more. They can get irritated by clothing rubbing against them.
Diagnosis & Tests
A seborrheic keratosis may turn black and may be difficult to distinguish from skin cancer. Sometimes such a growth must be removed and studied under a microscope to determine if it is cancerous or not.
Treatment & Prevention
Because seborrheic keratoses may grow larger over the years, removal is sometimes recommended especially if they itch, get irritated or bleed easily.
Both kinds of keratoses can be treated by some similar methods. One method is called cryosurgery, or freezing. A very cold liquid - liquid nitrogen - is applied to the growth with a cotton swab or spray gun in order to freeze it. The keratosis usually falls off within a few weeks. No mark is usually left when it heals, although occasionally there may be a small spot that will usually fade over time.
Another method is called curettage. The growths are removed by scraping them from the surface of the skin. An injection or spray is first used to numb the area before the growth is removed. No stitches are necessary, and bleeding is limited. Electrosurgery is another form of treatment. The growth is first numbed, then burned using an electric current, and scraped off.
Actinic keratoses are usually treated more aggressively than seborrheic keratoses because they can develop into skin cancer. Actinic keratoses can also be treated by retinoids (vitamin A derivatives), topical chemotherapy (5-fluoruracil), chemical peel, dermabrasion and laser skin resurfacing.
Prevention of actinic keratoses should ideally begin early in life. In geographic areas of high-intensity sunlight, sun damage to unprotected skin begins in childhood and puts a child at high risk for actinic keratoses and skin cancer later in life. However, it is never too late to initiate prevention of new actinic keratoses lesions in adulthood. Use protective (e.g. long-sleeved) clothing or a sunscreen with sun protection factor (SPF) of 15 or higher, applying it at least 15-30 minutes prior to sun exposure for maximum sun protection. Select a broad-spectrum sunscreen that provides both UVA and UVB protection. Sunscreen should be reapplied as necessary.
Complications
A small percentage of Actinic Keratoses do develop into invasive squamous cell carcinoma.
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Signs, symptoms & indicators of Keratoses:
Conditions that suggest Keratoses:
Recommendations and treatments for Keratoses:
KEY | | Proven definite or direct link |  | | May do some good |  | | Likely to help |  | | Highly recommended |
GLOSSARY
Actinic Keratoses
Actinic keratoses are common premalignant skin tumors that appear as small, raised, flaky lesions usually found on heavily sun-exposed skin in older people. They are mainly due to long-term exposure to the sun in susceptible persons and may progress to squamous cell carcinoma.
Cancer
Refers to the various types of malignant neoplasms that contain cells growing out of control and invading adjacent tissues, which may metastasize to distant tissues.
Carcinoma
Malignant growth of epithelial cells tending to infiltrate the surrounding tissue and giving rise to metastasis: An invasive malignant tumor derived from epithelial tissue that tends to metastasize to other areas of the body.
Chemotherapy
A treatment of disease by any chemicals. Used most often to refer to the chemical treatments used to combat cancer cells. Chemotherapy is usually given in cycles: a treatment period followed by a recovery period, then another treatment period, and so on. Most anticancer drugs are given by injection into a blood vessel (IV); some are given by mouth. Chemotherapy is a systemic therapy, meaning that the drugs enter the bloodstream and travel throughout the body. Usually, a patient has chemotherapy as an outpatient (at the hospital, at the doctor's office, or at home). However, depending on which drugs are given and the patient's general health, a short hospital stay may be needed.
Chronic (Chronicity)
Usually referring to chronic illness: Illness extending over a long period of time.
Estrogen (Oestrogen)
One of the female sex hormones produced by the ovaries.
Hyperkeratosis
Thickening of the skin.
Lesion (Lesions)
Any damage to tissue structure or function; an abnormal change in body tissue caused by disease or injury. A scar is a lesion, as is cancer, a stomach ulcer or a pimple.
Malignant (Cancerous)
Dangerous. Mainly used to describe a cancerous growth -- when used this way, it means the growth is cancerous and predisposed to spreading.
Melanoma
A life-threatening type of skin cancer that occurs in the cells (melanocytes) that produce melanin, the pigment found in skin, hair, and the iris of the eyes.
Mole (Moles, Nevi, Nevus)
Known more accurately as a "nevus", a mole is a lesion of the skin that may be present from birth, but which most often appears later in life. By three years of age, 40% of children will have at least one nevus. Some varieties are hereditary and most have color. A common nevus in light-skinned people is typically small, round, tan or brown, with a smooth border, and exactly the same throughout. Other types may be very large, or have irregular borders. There are dozens of different types, with many shapes, colors and sizes. While most are benign, malignant changes can occur to turn the benign nevus into a melanoma.
Seborrhea (Seborrheic)
Skin disease characterized by dry or moist, greasy, yellow crusts or scales. A disorder of the sebaceous glands, with changes in the amount and quality of the oils secreted. Although it can occur in any part of the body, seborrhea of the scalp (dandruff) is most common.
Seborrheic Keratoses
Seborrheic keratoses are raised growths on the skin. Seborrheic means greasy and keratosis means thickening of the skin. There may be just one or clusters of dozens. They usually start off light tan in color and then may darken to dark brown or nearly black. They may be oval spots a fraction of an inch across, or form long Christmas tree-like patterns on the torso that are inches long.
The consistent feature of seborrheic keratoses is their waxy, pasted-on or stuck-on look. The look is often compared to brown candle wax that was dropped onto the skin.
Topical
Most commonly 'topical application': Administration to the skin.
Vitamin A
A fat-soluble vitamin essential to one's health. Plays an important part in the growth and repair of body tissue, protects epithelial tissue, helps maintain the skin and is necessary for night vision. It is also necessary for normal growth and formation of bones and teeth. For Vitamin A only, 1mg translates to 833 IU.
Last updated: Dec 20, 2008
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