Chapter 9

1. Anatomy and Physiology of the Integumentary System

The integumentary system consists of the skin and its accessory structures (hair, nails, and glands). Its primary role is protection from microbes and trauma, but it also regulates temperature, retains fluids, and provides sensory input.

The Three Layers of Skin
  • Epidermis: The thin, outermost layer. It is avascular (no blood supply).
    • Stratum Germinativum: The deepest part where new cells are born.
    • Keratinization: The process where cells become flat and waterproof as they move up.
    • Melanocytes: Produce melanin to protect against UV radiation.
  • Dermis: The second, thick layer made of vascular connective tissue. It contains nerves for touch and pain and helps regulate body temperature by dilating or constricting blood vessels. It typically ranges from 1 to 4 mm in thickness.
  • Subcutaneous Layer (Hypodermis): Not technically skin, but an anchor for the layers above. Composed of fat and connective tissue, which provides a cushion, insulation, and a calorie reserve.
Appendages
  • Hair: Formed by epidermal cells in the dermis. Nutrient supply comes from the papilla.
  • Nails: Hard plates of keratin. The lunula is the white crescent at the base representing new growth. The vascular nail bed helps assess oxygenation and perfusion.
  • Glands:
    • Eccrine Sweat Glands: Found everywhere (especially palms/soles) for cooling.
    • Apocrine Sweat Glands: Found in axillae/genitalia; activated at puberty; cause body odor.
    • Sebaceous Glands: Secrete lipid-rich sebum to lubricate skin and hair.

2. General and Problem-Based Health History

Assessment begins by gathering subjective data to identify risks or underlying systemic diseases.

Present and Past Health Status
  • Chronic Illnesses: Conditions like liver or renal failure can cause skin discoloration or itching.
  • Medications: Many drugs cause side effects like rashes, sun sensitivity, or skin thinning.
  • Allergies: Essential for identifying the cause of hives or dermatitis.
Problem-Based History (OLD CARTS)

When a patient reports a symptom (pruritus, rash, pain, or wounds), the nurse uses OLD CARTS:

  • Onset, Location, Duration, Characteristics, Aggravating factors, Related symptoms, Treatment, and Severity.
  • Pruritus (Itching): Can indicate allergies, dry skin (xerosis), or systemic diseases like lymphoma.
  • Wounds: The location can point to the cause—e.g., lower leg wounds often relate to poor perfusion/circulation.

3. Pressure Ulcer Assessment (Limited Mobility)

Pressure injuries occur due to sustained pressure, shear, or friction, especially over bony prominences.

  • Stage 1: Intact skin with nonblanchable redness (doesn't turn white when pressed).
  • Stage 2: Partial-thickness loss; looks like a shallow open ulcer or a blister with an exposed dermis.
  • Stage 3: Full-thickness loss; subcutaneous fat may be visible, but no bone or muscle.
  • Stage 4: Full-thickness loss with exposed bone, tendon, or muscle.
  • Unstageable: The base is covered by slough (yellow/gray) or eschar (tan/black), making depth impossible to see.
  • Deep Tissue Injury: Purple or maroon intact skin indicating damage to underlying soft tissue.

4. Common Skin Pathologies

  • Viral:
    • Herpes Zoster (Shingles): Reactivation of chickenpox; clusters of vesicles along a sensory nerve (dermatome).
    • Herpes Simplex: Grouped vesicles on an erythematous base (cold sores or genital herpes).
  • Bacterial:
    • Cellulitis: A warm, red, tender infection of the skin and subcutaneous tissue.
    • Furuncle (Abscess): A localized, painful, pus-filled lesion originating from a hair follicle.
  • Fungal:
    • Tinea: Ringworm (corporis), athlete's foot (pedis), or scalp infection (capitis).
    • Candidiasis: A red, scaly rash with sharp borders, common in moist skinfolds.
  • Inflammatory:
    • Atopic Dermatitis: Chronic, itchy, red lesions often associated with asthma/allergies.
    • Psoriasis: Silvery scales on raised red plaques, often on elbows and knees.

5. Skin Cancers and Primary Prevention

  • Basal Cell Carcinoma: Most common; shiny, nodular, or ulcerated; rarely spreads.
  • Squamous Cell Carcinoma: Red, scaly patch with sharp margins; invasive.
  • Melanoma: The most lethal; uses the ABCDE rule for assessment:
    • A: Asymmetry
    • B: Border irregularity
    • C: Color variation
    • D: Diameter (typically > 6 mm)
    • E: Evolving (changing size, shape, or color)
  • Health Promotion: Use sunscreen with SPF \geq 15, wear protective clothing, and avoid midday sun (10 AM–4 PM).

6. Skin Lesions Caused by Abuse

  • Bruises (Ecchymosis): Look for patterns (like loop marks from electrical cords) and note the color to estimate age (1–3 days is purple/black; 6–15 days is yellowish).
  • Bites: Ovoid tooth marks, often found on genitals or buttocks in child abuse.
  • Burns: "Stocking" or "glove" patterns from immersion in hot water and "branded" patterns from contact with objects like cigarettes or irons.