Actinic keratosis

Actinic keratosis (also called solar keratosis, senile keratosis, or AK) is a premalignant condition of thick, scaly, or crusty patches of skin. It is most common in fair-skinned people who are frequently exposed to the sun, because their pigment isn't very protective. It usually is accompanied by solar damage. Since some of these pre-cancers progress to squamous cell carcinoma, they should be treated.

When skin is exposed to the sun constantly, thick, scaly, or crusty bumps appear. The scaly or crusty part of the bump is dry and rough. The growths start out as flat scaly areas, and later grow into a tough, wart-like area.

An actinic keratosis site commonly ranges in between 2 to 6 millimeters, and can be dark or light, tan, pink, red, a combination of all these, or the same pigment of ones skin. It may appear on any sun-exposed area, such as the face, ears, neck, scalp, chest, back of hands, forearms, lips etc.

Epidemiology

Actinic keratosis may appear as early as 30 years of age in susceptible people who spend a lot of time outdoors. People with skin phototypes I and II are more likely to be affected, as are albinos and Immunosuppressed patients (Marshall, 1974; Fitzpatrick, 1988; Abel 1989; Lookingbill et al, 1995). As much as 100% of elderly whites get AK (Gordon and Silverstone, 1969; Scotto et al, 1983), but is rare in darker-skinned people. About 10% of people with AK eventually develop squamous cell carcinoma of the skin (Glogau, 2000).

Prevention

Preventative measures recommended for AK are similar to those for skin cancer:

Not staying in the sun for long periods of time without sunscreen.
Frequently applying powerful sunscreens with SPF ratings greater than 15 and that also block both UVA and UVB light.
Using sunscreen even in winter sun exposure.
Wearing clothing such as hats, long-sleeved shirts, long skirts, or pants.
Avoiding sun exposure during noon hours is very helpful because ultraviolet light is the most powerful at that time.

Diagnosis

Doctors can usually identify AK by doing a thorough examination. A biopsy may be necessary when the keratosis is large and/or thick, to make sure that the bump is a keratosis and not a skin cancer. Seborrheic keratoses are other bumps that appear in groups like the actinic keratosis but are not caused by sun exposure, and are not related to skin cancers. Seborrheic keratoses may be mistaken for an actinic keratosis.

Treatment

Various modalities are employed in the treatment of actinic keratosis:

Cryosurgery, e.g. with liquid nitrogen, by "freezing off" the AKs.
5-fluorouracil (a chemotherapy agent): a cream that contains this medication causes AKs to become red and inflamed before they fall off.
Photodynamic therapy: this new therapy involves injecting a chemical into the bloodstream, which makes AKs more sensitive to any form of light.
Electrocautery: burning off AKs.
Immunotherapy: topical treatment with imiquimod (Aldara™), an immune enhancing agent
Different forms of surgery.

Regular follow-up after treatment is advised by many doctors. The regular checks are to make sure new bumps have not developed and that old ones haven't become thicker and/or have skin disease.

External links

References

Scotto J, Fears TR, Fraumeni JF. Incidence of nonmelanoma skin cancer in the United States. Publication No (NIH) 82-2433. Washington, DC: US Dept Health and Human Services; 1983.