Chapter 17: Skin Lesions

Rosacea is presented as a distinct chronic inflammatory disorder characterized by facial erythema, flushing, telangiectasia, and papulopustular inflammation without comedones, managed through trigger avoidance and topical metronidazole therapy. Seborrheic keratosis represents a common benign growth in aging populations that typically requires no intervention unless cosmetically problematic. The chapter then addresses premalignant lesions, particularly actinic keratosis arising from cumulative ultraviolet damage in sun-exposed skin, which carries potential for progression to squamous cell carcinoma and requires preventive destruction through topical or ablative therapies. Malignant skin cancers receive substantial coverage, with melanoma presented as the most lethal form using the ABCDE diagnostic criterion for identifying asymmetry, border irregularity, color variation, diameter greater than six millimeters, and evolving characteristics, requiring urgent excisional biopsy and wide surgical margins with consideration of lymph node dissection and targeted immunotherapies. Nonmelanomatous skin cancers, including basal cell carcinoma as the most prevalent skin cancer and squamous cell carcinoma with higher metastatic potential, are discussed with emphasis on their ultraviolet etiology and treatment options ranging from simple excision to Mohs micrographic surgery. Throughout the chapter, patient education emphasizing monthly self-examination, sun protective behaviors, and early detection is presented as fundamental to preventing progression and improving survival outcomes.