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Skin Lesions and Diagnosis. James H Herndon MD Clinical Professor, Dermatology UT Southwestern Medical Center. Skin Lesions and Diagnosis. Recognition of the significant can be life- and health-saving (melanoma, RMSF, vasculitis)
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Skin Lesions and Diagnosis James H Herndon MD Clinical Professor, Dermatology UT Southwestern Medical Center
Skin Lesions and Diagnosis • Recognition of the significant can be life- and health-saving (melanoma, RMSF, vasculitis) • Failure to recognize normal/inconsequential can also cause harm (the black seborrheic keratosis, pigmentary purpura of the lower legs, physiologic variations in genital areas)
Skin Lesions and Diagnosis • Skin acts as window in several ways. Two examples: • Point mutations may cause skin and internal change. • Birt-Hogg-Dube Syndrome causes cutaneous fibrofolliculomas, renal tumors, and spontaneous pneumothorax by affecting the folliculin gene. • Hormonal overdose causes skin and internal change. • PCOS causes elevated androgens -> acne, hirsutism and also hyperinsulinemia -> acanthosis nigricans and diabetes
Skin Lesions and Diagnosis • How to bring order to confusion: • What component is mainly affected? (dermis, epidermis, subcutaneous fat, blood vessels) • What is the primary change and what is secondary? • Next assess the lesions by type, shape, arrangement, and distribution. • Finally, how did the changes evolve over time?
Skin Lesions and Diagnosis • How to bring order from confusion, continued. • History should contain: exact description of onset, first lesions if any, details of development. • Prior treatment, of home or physician source, and the diagnosis(es) based on. • Other drugs, herbal remedies, ethnic medications. • Effect of sunlight, season, contact with immediate environment (plants, animals, chemicals, metals). • Role of physiologic changes (menses, pregnancy).
Skin Lesions and Diagnosis • Why do experienced clinicians often view the rash before taking a history? • Visual diagnosis may be sharper without preconceived ideas. • Some lesions and patterns are so distinctive that history is needed only as confirmation. • In other cases the rash guides and interacts with the history, allowing one to diagnose more efficiently.