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Actinic keratosis (AK) is a common skin condition due to cumulative exposure to UV radiation mainly affecting the head, face, and neck of the elderly. Lesions present as erythematous or keratotic patches and plaques. They are often accompanied by signs of actinic damage such as telangiectasia and mottled skin pigmentation. AK can progress to invasive cutaneous squamous cell carcinoma. Therefore, early and consequent treatment is recommended in the pertinent treatment guidelines. The treatment approach can target single lesions (“lesion-directed”) or an entire field (“field-directed”). Therapy should be based on the localization of the AK, size of the treatment field, clinical severity, and risk factors such as immunosuppression. Combination and sequential therapies may enhance the lesion clearance in severe and widespread AK. Prevention of herpes simplex infection or recurrence with acyclovir, valacyclovir, or famciclovir should be considered for ablative laser resurfacing and large-field dermabrasion, but is usually dispensable for topical drug-mediated approaches. Sun protection is recommended as basic prevention measure in all AK patients. Oral retinoids and nicotinamide can be considered for prevention in high-risk patients. If patients receive retinoids caution is called for ablative procedures such as chemical peeling, dermabrasion, or ablative lasers to avoid increased scarring. See Table 99-1.
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