Monday, July 16, 2007

Seborrheic Keratosis, Solar Lentigines, and Actinic Keratosis

 Updated 3/2017-- photos and all links (except to my own posts) removed as many no longer active.

Seborrheic keratoses are raised growths on the skin. Seborrheic means greasy and keratosis means thickening of the skin. They may occur as just one or clusters of many. They usually start off light tan and may darken to dark brown or nearly black. The most consistent feature of seborrheic keratoses is their waxy, "pasted-on" or "stuck-on" look. The look is often compared to brown candle wax that has been dropped onto the skin. They may be unsightly, but are not contagious and do not spread. They do not have any relationship to skin cancer, and never turn into melanom. They do not pose a health risk.

As people age they may develop more. Sometimes they seem to erupt during pregnancy, following hormone replacement therapy or as a result of other medical problems. They are most likely hereditary and not caused by sun exposure. They often are found on the trunk and on the face where the facial skin meets the scalp. They may be oval spots less than a fraction of an inch across, or may form long Christmas tree like patterns on the torso.

Clothing rubbing against them may irritate and make them grow larger. Alpha-hydroxy lotions and mild steriod creams may help this. If they get very itchy, irritated, or bleed easily they should be removed. When a seborrheic keratosis turns black, it may be difficult to distinguish it from a skin cancer without a biopsy.

Removal is often done using liquid nitrogen (cryosurgery). Another treatment done (as they are superifical–"pasted-on") consist of scraping off the lesion with a curette (ED&C). This is more useful when only a few need to be done or when one spot needs a biopsy (as the scrapings can be sent to the lab). Sometimes they are burnt off with an electric needle or laser.

Liver or age spots are solar lentigines. They are benign lesion that occur on sun-exposed areas of the body. The backs of the hands and face are the most common areas. They tend to increase in number with age. They can vary in size from 0.2 to 2 cm. Lenigines are flat, dark lesions that usually have discrete borders and may have an irregular shape. They are are caused by a marked increase in the number of pigment cells (melanocytes) located in the superficial layers of the skin. Lentigines are benign and no treatment is necessary. For cosmetic purposes, some are treated with cryotherapy, hydroquinone preparations (bleaching creams), retinoids, chemical peels or lasers. Preventive measures include avoidance of excessive sunlight. If a lesion develops a highly irregular border, changes in pigmentation, or changes in the thickness, then a biopsy should be done to rule out cancer.

Actinic keratosis, unlike seborrheic keratoses (AK’s), are from sun damage. They are also called solar keratosis, sun spots, or precancerous spots. They appear as a scaly or crusty bump on the skin surface. They range in size from as small as a pinhead to over an inch in diameter. AK’s may be light or dark, tan, pink, red, a combination of these, or the same color as the skin. They may be flat or raised in appearance. They may disappear only to reappear later. Half of all keratosis will go away on their own if one avoids all sun for a few years (difficult to do). AK’s appear on sun exposed areas: face, ears, bald scalp, neck, backs of hands and forearms, and lips.
Actinic keratosis can be the first step in the development of skin cancer. They are pre-cancer. It is estimated that 10-15 % of active lesions will progress to squamous cell carcinoma (SCC). The presence of AK’s indicates that sun damage has occurred. This increases the likelihood of any kind of skin cancer, not just SCC, can develop. People with AK’s are more likely to develop melanoma also. Sun exposure is the cause of almost all actinic keratoses. So use your sunscreen. Don’t forget the lip balm with sunscreen. Wear your hats, preferably wide brimmed.

The most aggressive form of keratosis, actinic cheilitis, appears on the lips and can evolve into squamous cell carcinoma. When this happens, roughly one-fifth of these carcinomas metastasize. It occurs primarily in men and does not present until after 50 years of age, but the cause is often extreme sun exposure during the teen years and young adult life. Life-time occupational sun exposure increases the risk. The lip becomes puffy and blotchy red and pale pink, with occasional white plaques (leukoplakia) and chronic ulcers. This is a precancer, with an estimated 6% risk of cancer development. Treatment is close follow-up and removal of thick white or white/red patches or nonhealing ulcers. Extensive lesions require complete removal of the lip mucosa and replacement with mucosa inside the mouth.

Cryosurgery freezes off the lesions through application of liquid nitrogen. This is done with a special spray device or cotton-tipped applicator. It does not require anesthesia and produces no bleeding. The longer the spot is frozen the better the chance it will never come back. Longer freezes can result in hypopigmented areas.
Curettage scrapes the lesion off and may be used as a biopsy specimen. Bleeding is controlled by cautery (application of an acid or heat produced by an electric needle).
Shave Removal utilizes a scalpel to shave the keratosis (provides a specimen). As with curettage, the base of the lesion is destroyed and the bleeding stopped by cauterization.
Chemical Peels make use of acids (Jessners solution and /or trichloroacetic acid) applied over the area. The top layers of the skin are "peeled" off by controlled burning (done by the acid strength used and time left on the skin). It may take up to seven days for the area to heal. Redness and soreness associated with the peel usually disappear after a few days.
Topical creams used to treat keratoses is an effective solution when there are numerous lesions. Aldara works by stimulating the body’s immune system to "recognize" these precancerous lesions and treat them. This ointment is applied to the affected areas twice weekly for 6-12 weeks. 5-fluorouracil (Efudex, Carac) cream works by directly attacking the precancerous cell. This ointment is applied once or twice daily for 2-4 weeks. Treatment leaves the affected area temporarily reddened and raw. The more raw and inflamed the skin becomes, the better the end result. Solaraze gel is a non-steroidal medication that also works fairly well on AK’s. This ointment is applied twice daily for 90 days.

Regular follow-up visits with your dermatologist is recommended to "catch" these pre-cancerous lesions and treat them before they evolve into skin cancer (SCC or melanoma).


denverdoc said...

I think my skin's warranty just ran out as I am newly awash in solar lentigines. If the skin tags don't scream 'she's old,' the lentigines do.

So I could just freeze off those creepy seborrheic keratoses in my office with those little throw away liquid nitrogen cannisters? People hate them so--like so many barnacles on so many crepey old torsos.


Peter said...

Hi! I'm about to undergo (Jan) Aldara treatment to my face in the prelude to more MOHs surgery. Wish me luck!

Take Care,