Overview
This lecture covers the purpose and components of the integumentary (skin) exam, how skin findings relate to other pathologies, and common skin malignancies.
Functions and Structure of the Skin
- The skin is the body's largest organ, accounting for about 16% of body weight.
- Main functions: protection, insulation, fluid regulation, infection defense, sensory input, and vitamin D production.
- Skin layers: epidermis (outer), dermis (middle/thickest), and hypodermis (subcutaneous tissue).
- Hair and nails are also part of the integumentary system.
Components of the Integumentary Exam
- Start with a full review of systems and look for red/yellow flags.
- Visual inspection includes skin color, comparison between limbs, and sun-exposed vs. non-exposed areas.
- Assess bruising (color changes over time), hemocitarin staining (brown in lower legs from venous insufficiency), and petechiae (small red/purple spots from capillary bleeding).
- Cyanosis (bluish/greyish tint) suggests low oxygen, seen in cold, heart/lung disease, or hemoglobin disorders.
- Jaundice (yellowing of skin/eyes) indicates liver or hemolytic disease.
- Erythema (redness) indicates inflammation, infection, allergy, burn, or radiation and can be blanchable or non-blanchable (pressure ulcers).
- Inspect for swelling (in joints or tissues) and measure as needed.
Hair and Nail Assessment
- Sparse/coarse hair: hypothyroidism; fine hair: hyperthyroidism; dry/brittle hair: malnutrition; distal hair loss: peripheral artery disease.
- Lanugo hair (fine “peach fuzz”): normal in infants, may indicate anorexia nervosa in adults.
- Normal nails: smooth, arched, uniform pink color.
- Abnormal findings: grooves, white lines, color differences, spooning, clubbing (low oxygen), pits, yellowing/thickening (fungal infection).
Additional Skin Tests
- Temperature: warm (infection/inflammation), cold (reduced blood flow). Use dorsal hand to compare sides/proximal-distal.
- Texture: check for scars, thickening (venous insufficiency).
- Moisture: normal is slightly moist; very dry (arterial insufficiency), overly moist (anxiety).
- Hydration: skin turgor test; return >3s suggests dehydration.
- Sensation: test sharp/dull, vibration (tuning fork), protective sensation (10g monofilament).
Common Skin Malignancies
- Basal cell carcinoma: open sore, bleeds/crusts, pearly bump, typically easy to treat.
- Squamous cell carcinoma: sore that doesn't heal, irregular borders, scaly/crusty, bleeds.
- Malignant melanoma: most dangerous, can spread, use ABCDE rule—Asymmetry, Border irregularity, Color changes, Diameter > pencil eraser, Evolving.
Key Terms & Definitions
- Hemocitarin staining — brown discoloration from iron pigment, often in lower legs due to venous insufficiency.
- Petechiae — small red or purple skin spots from capillary bleeding.
- Cyanosis — bluish or grayish skin/mucosa due to low oxygen.
- Jaundice — yellowing of skin/eyes from liver/hemolytic disease.
- Erythema — redness of skin from increased blood flow.
- Lanugo hair — fine, soft hair, normal in infants, can indicate eating disorders.
- Clubbing — rounded, bulbous nail tips, sign of chronic low oxygen.
- ABCDE rule — system for assessing moles: Asymmetry, Border, Color, Diameter, Evolving.
Action Items / Next Steps
- Practice visual and physical assessment procedures discussed.
- Review the characteristics and significance of common skin lesions.
- Prepare for the next lecture on further integument exam components.