ACTINIC KERATOSIS.

[gmohan]

Actinic keratosis (AK), also known as solar keratosis, refers to the 'crusty' lesions appearing on sun-exposed areas (face, bald scalp, lips, backs of hands) caused by cumulative damage from the sun's ultraviolet rays.

They present as erythematous keratotic macules, papules and plaques, and are identified histologically as an intraepithelial proliferation of abnormal keratinocytes.

Caucasians with a fair complexion, with blond or red hair, and with blue, green or grey eyes, have a slightly higher incidence, and AK is more commonly seen in men than in women. Older people are more likely to develop AK, due to the cumulative effect of UV damage, as are the immunocompromised.

Left untreated, up to 10% of AKs may advance to squamous cell carcinoma — the second most common form of skin cancer — within 10 years, ie. when atypical keratinocytes identified histologically have extended beyond the basement membrane.
This impact is large:
40-60% of squamous cell cancers begin as untreated AK, and 2-10% of the squamous cell cancers spread to internal organs. Because of the risk of progression of AK to squamous cell cancer, and because of the inability to predict the behaviour of individual lesions, all AK must be treated.

Topical medications for the treatment of AK are many and effective, including:
Diclofenac (a non-steroidal anti-inflammatory used in combination with hyaluronic acid)
5-fluorouracil
Imiquimod
Ingenol mebutate

Non-topical options include cryosurgery, combination therapy (for example, 5-FU followed by cryosurgery), chemical peeling (with trichloroacetic acid or similar), laser surgery (carbon dioxide erbium YAG) and photodynamic therapy (with 5-aminolevulinic acid, which photosensitises the lesion).

The best way to prevent AK is to protect the skin from the sun: do not burn, seek the shade between the hours of 10 and 4, use a broad-spectrum sunscreen, cover up with clothing, examine your skin regularly, consult your doctor for regular skin examinations and avoid tanning booths.

G Mohan.