Dermoscopy of Actinic Keratosis

Overview / Definition Actinic keratosis (AK) is a common skin condition that arises from chronic sun exposure, leading to localized hyperkeratosis and atypical keratinocyte proliferation. It is often considered a precancerous lesion, as it has the potential to progress to squamous cell carcinoma (SCC) if left untreated. Epidemiology Actinic keratosis predominantly affects individuals with fair skin, especially those with a history of significant sun exposure. Prevalence increases with age, particularly in those over 40 years. Higher incidence in individuals living in sunny climates. Immunocompromised patients are at higher risk for developing AK and its progression to SCC. Pathophysiology / Mechanism The development of actinic keratosis is primarily due to the cumulative effects of ultraviolet (UV) radiation on the skin. The UV rays cause direct DNA damage in keratinocytes, leading to mutations that disrupt normal cellular function. Key mutations often occur in oncogenes (e.g., TP53) and tumor suppressor genes. The resulting keratinocytes exhibit abnormal differentiation and proliferation. Clinical Presentation Clinically, AK presents as rough, scaly patches on sun-exposed areas such as the face, ears, scalp, and hands. Lesions may be erythematous or skin-colored. Commonly, patients report a sensation of itching or burning. Lesions vary in size from a few millimeters to several centimeters. Diagnosis / Workup Diagnosis of actinic keratosis is primarily clinical, but dermoscopy provides valuable insights into the characteristics of the lesion. Dermoscopy may reveal: Scattered telangiectasias Keratin plugs Background erythema Irregular pigmentation A biopsy may be warranted in uncertain cases to rule out squamous cell carcinoma. Treatment / Management Treatment of actinic keratosis aims to remove the lesions and prevent progression to skin cancer. Common treatment modalities include: Topical therapies (e.g., 5-fluorouracil, imiquimod, diclofenac) Cryotherapy (liquid n