Summary Actinic Keratosis is an epidermal pre-malignant lesion caused by sun exposure that may predispose to squamous cell carcinoma of the skin. Diagnosis is made with a biopsy showing hyperkeratotic cells and lower epithelial cells showing loss of polarity and hyperchromatic nuclei Treatment is usually cryotherapy. Epidemiology Demographics common in fair-skinned individuals common in elderly patients Risk factors results from significant lifetime sun exposure keratinocyte damage Etiology Associated conditions may lead to squamous cell carcinoma Presentation Symptoms typically asymptomatic occasionally tender Physical exam thin, adherent transparent or yellow scale that progressively increases in thickness often with telangiectasias can progress to cutaneous horn difficult to distinguish from squamous cell carcinoma at this point rough, “sand-paper” texture often easier to detect by palpation rather than observation frequently on sun-exposed areas face, head, neck, dorsal hands, ears Evaluation Skin biopsy dysplastic epidermis with keratinocyte atypia hyperkeratotic cell with lower epithelial cells showing loss of polarity and hyperchromatic nuclei no invasion into dermis Differential Squamous cell carcinoma Actinic cheilitis Lentigo maligna Treatment Prevention Annual follow-up for skin cancer monitoring avoid sun exposure use sunscreen Lifestyle modification avoid sun exposure use sunscreen Surgical liquid nitrogen (cryotherapy) = most common treatment electrodesiccation and curettage Pharmacological topical 5-fluorouracil typically reserved for those with widespread actinic keratoses Complications Prognosis typically slow-growing and persistent if untreated Prevention avoid sun exposure use sunscreen Complications risk of progression to squamous cell carcinoma Prognosis Typically slow-growing and persistent if untreated