Actinic Keratosis: Field Treatment and Progression Risk

Overview / DefinitionActinic keratosis (AK) is defined as a localized, thickened area of skin that develops due to the cumulative effects of ultraviolet (UV) radiation exposure. It is considered a precursor to squamous cell carcinoma (SCC) and is commonly found on sun-exposed areas such as the face, ears, scalp, and dorsal hands.EpidemiologyAK is prevalent in populations with a history of significant sun exposure, particularly in individuals with fair skin types. The incidence increases with age, with a higher prevalence observed in individuals over 40 years of age. Key epidemiologic facts include:Estimated prevalence rates of up to 58% in older adults.Higher incidence among males compared to females.Increased risk in immunocompromised individuals.Pathophysiology / MechanismThe pathophysiology of AK involves damage to keratinocytes from UV radiation, leading to genetic mutations and abnormal keratinocyte proliferation. Notably, the following mechanisms are involved:UV radiation induces DNA damage, specifically in the p53 tumor suppressor gene.Chronic inflammation and oxidative stress contribute to the pathogenesis.AK lesions show disordered keratinocyte differentiation.Clinical PresentationClinically, AK presents as dry, scaly patches that may be erythematous and can range from 2mm to several centimeters in diameter. Key characteristics include:Lesions may feel rough or sandpaper-like to the touch.Commonly located on sun-exposed areas: face, ears, scalp, and back of hands.May be asymptomatic or cause mild itching or tenderness.Diagnosis / WorkupThe diagnosis of AK is primarily clinical, based on the characteristic appearance of the lesions. However, in ambiguous cases, a biopsy may be performed. Important points in the workup include:Detailed patient history regarding sun exposure and previous skin lesions.Physical examination to assess the extent and nature of lesions.Consideration of dermoscopy to evaluate atypical lesions.Treatment / ManagementManagement of AK fo