If you have had any amount of unprotected sun exposure and you are between the ages of 30 and 80 you might have noticed uneven, rough-feeling, slightly raised, occasionally crusty, and generally light brown or light pink patches on your chest, hands, arms, or neck. These discolorations are called actinic keratosis or solar keratosis, and are distinct from other types of brown discolorations that show up on skin. According to the Skin Cancer Foundation, “One in six people will develop an actinic keratosis in the course of a lifetime.” The more typical brown spots that appear on skin due to sun exposure are called melasmas. Melasmas look more like brown freckling and are not raised, rough, or crusted, and are considered benign. Actinic keratosis, though not cancerous, are problematic because they are considered indicative of a precancerous skin condition and require evaluation by a dermatologist. If you are in doubt whether a brown patch on your skin is a melasma or an actinic keratosis, it is best to ask your doctor. (Source: Journal of Oral Maxillofactory Surgery, June 2008, pages 1162-1176.)
Prevention is the best method of averting the occurrence of these types of brown patches, and that means daily and liberal use of effective sunscreens. Unfortunately, because most of us were not aware of appropriate sun protection for much of our lives, many of us have a pretty good chance of seeing one of these patches crop up somewhere on our bodies.
There are a number of ways to deal with removing actinic keratosis. The primary techniques are curettage, cryosurgery, and photodynamic therapy, plus topical chemotherapy options (Sources: Dermatology Therapy, September-October 2008, pages 412-415; and American Journal of Clinical Dermatology, May-June 2000, pages 167-179).
Deciding what to do depends primarily on the status of the lesion and how much the appearance bothers you. This requires a discussion with your dermatologist to evaluate your various options.
A typical method of removal is to scrape or cut the lesion off with procedures called curettage, electrodesiccation, or even simple scraping with a surgical razor. Curettage refers to cutting out the lesion with a curette, a spoon-shaped implement that has a sharp edge. Electrodesiccation uses an electric current to remove the skin tissue while it simultaneously controls bleeding. In both instances a biopsy is done to check on the status of the lesion. Both of these methods can cause scarring, and recurrence of the lesions is a problem.
Cryosurgery uses extreme cold, in the form of liquid nitrogen, to get rid of the unwanted tissue. This method doesn’t cause bleeding or scarring but it can leave behind a white mark that often doesn’t regain normal skin color. There is also a strong likelihood of recurrence.
When there are numerous actinic keratosis lesions present, two topical medications are sometimes used. The first, 5-fluorouracil (brand name Efudex), a chemotherapy agent for some cancers, is applied to the spots twice a day for three to five weeks. The side effects of this treatment can be significant, though temporary. Inflammation, burning, stinging, crusting, and some discomfort or pain are typical, but healing takes place one to two weeks after treatment is discontinued. It is considered a highly effective treatment.
Another chemotherapy agent used topically, masoprocol cream, 10% (brand name Actinex), is similar to 5-fluorouracil in terms of application and results, although there is a far higher risk of contact dermatitis with masoprocol than with 5-fluorouracil.
Immune response modulators are capable of selectively destroying abnormal skin cells. In a small study group “six men with actinic keratosis were treated with imiquimod 5% cream (trade name Aldara) three times a week for 6-8 weeks. In the event of a local skin reaction treatment was modified to two times per week. Results: All the AK [actinic keratosis] lesions
were successfully cleared___ Histologically [under the skin], no apparent signs of persisting
AK could be detected, and no recurrences were reported during follow up” (Source: British Journal of Dermatology, May 2001, pages 1050-1053). Aldara is a potential option to discuss with your physician.
Chemical peeling uses trichloroacetic acid (TCA), which is applied under light sedation. Much like any other cosmetic chemical peel, this causes the top layers of the skin to slough off, to be replaced within a few weeks by growth of new skin. A TCA peel is used when deeper penetration is needed to remove the lesion. The downsides to this method are the need for sedation, which makes it rather inconvenient, and the prolonged healing time; the upside is that the eventual results are considered quite good.
The newest treatment recently approved by the FDA is called photodynamic therapy. This is an interesting procedure that involves the topical application by a physician of a prescription-only cream containing aminolevulinic acid (brand name Levulan Kerastick). About 14 to 18 hours after the cream has been applied, the area is exposed to a particular light source, called BLU-U or Blue Light, for approximately 15 to 20 minutes. This is considered a very successful treatment with little risk to skin. However, after the aminolevulinic acid has been applied, the skin becomes abnormally sensitive to daylight or bright indoor lighting until the treatment is completed. It is critical to wear sunlight-protective clothing and to avoid any exposure to the sun because sunscreens will not protect you. It is also important to avoid sitting close to any light source. Side effects during treatment usually include burning, a crawling feeling on skin, itching, numbness, and stinging sensations, darkening or lightening of treated skin, crusting, scabs, and red itchy bumps. However, once treatment is discontinued the reaction and brown spots are gone and tend not to return.