Actinic keratosis
Actinic keratosis (also called solar keratosis, or AK) is a premalignant condition of thick, scaly, or crusty patches of skin. It is more common in fair-skinned people, especially those who are frequently exposed to the sun, as it is usually 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 between 2 and 6 millimeters in size, and can be dark or light, tan, pink, red, a combination of all these, or have the same pigment as the surrounding skin. It may appear on any sun-exposed area, such as the face, ears, neck, scalp, chest, backs of hands, forearms, or lips.
Preventive measures recommended for AK are similar to those for skin cancer:
- Not staying in the sun for long periods of time without protection (e.g.:sunscreen, clothing, hats).
- Frequently applying powerful sunscreens with SPF ratings greater than 30 and that also block both UVA and UVB light.
- Wearing sun protective 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:
- Diclofenac sodium 3% gel, e.g. Solaraze in Australia, contains nonsteroidal anti-inflammatory drug. Recommended duration of therapy is 60 to 90 days.
- 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.
- Laser, notably CO2 and Er:YAG lasers. A Laser resurfacing technique is often used with diffuse AKs.
- Electrocautery: burning off AKs with electricity.
- Immunotherapy: topical treatment with imiquimod (Aldara), an immune enhancing agent.
- Different forms of surgery.
Regular follow-up after the treatment is advised by many doctors. The regular checks are to make sure no new bumps have developed and that old ones haven't become thicker.
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