Chapter 13: Skin, Hair & Nails
Chapter 13: Skin, Hair, and Nails
Skin as an Organ System
Body's Largest Organ System:
Covers approximately 20 square feet of surface area in adults.
Acts as a sentry guarding the body.
Layers of Skin:
Epidermis: The outer highly differentiated layer.
Contains the Basal Cell Layer, which forms new skin cells.
The Outer Horny Cell Layer consists of dead keratinized cells.
Dermis: The inner supportive layer.
Composed of connective tissue or collagen and elastic tissue.
Subcutaneous Layer: Below these layers, made up of adipose tissue.
Functions:
Stores fat for energy.
Provides insulation for temperature control.
Aids in protection.
Skin Color
Derived from Three Sources:
Melanin: Brown pigment.
Carotene: Yellow-orange pigment.
Red-purple tones from the underlying vascular bed.
Individual variations in the amount of red, yellow, and brown pigmentation can affect prevailing skin color, modified by:
Thickness of skin.
Presence of edema (swelling).
Hair, Sebaceous & Sweat Glands
Hair Structure:
Composed of threads of keratin including the hair shaft and bulb matrix.
Types of hair:
Vellus Hair: Fine, soft hair.
Terminal Hair: Coarser hair.
Hair Follicles:
Exhibit cyclical patterns with active and resting phases.
Sebaceous Glands:
Secrete sebum, a lipid substance through hair follicles.
Functions:
Lubricate skin.
Form an emulsion with sweat to keep skin moist.
Sweat Glands:
Eccrine Glands: Produce sweat directly on skin surface.
Apocrine Glands: Produce milky secretion and open into hair follicles.
Properties and Functions of Skin
The skin is waterproof, protective, and adaptive.
Functions include:
Protection from external environment.
Prevention of penetration of harmful substances.
Perception of sensations (touch, pain, temperature).
Temperature regulation.
Identification and communication through cosmetic features.
Wound repair capability.
Absorption and excretion of substances.
Production of Vitamin D through exposure to sunlight.
Developmental Changes in Skin
Infants & Children
Newborns:
Have lanugo, a fine downy hair.
Vernix Caseosa: A thick, cheesy substance that protects the skin in utero.
Sebum: Helps to hold water in the skin, producing milia (small white cysts).
Children:
The epidermis thickens, darkens, and becomes lubricated.
Hair growth accelerates.
Adolescents:
Increased secretions from apocrine sweat glands.
Increased subcutaneous fat deposits.
Development of secondary sex characteristics.
Pregnant & Aging Individuals
Pregnant Women:
Increased metabolism leads to increased secretion of sweat and sebaceous glands to cool the body.
Skin color changes due to increased hormone levels.
Fat is deposited as maternal reserves for nursing.
Aging Process:
Loss of skin elasticity leads to skin folds and sagging.
Decreased number and function of sweat and sebaceous glands leads to dry skin.
Senile Purpura: Discoloration caused by increased capillary fragility.
Slower skin cell replacement and delayed wound healing.
Decreased functioning of melanocytes leads to gray fine hair.
Subjective Data Collection
History Taking: Important questions include:
Past medical history of skin diseases, allergies, hives, psoriasis, or eczema.
Changes in pigmentation or moles (size, color).
Symptoms like excessive dryness or moisture, pruritus, or bruising.
Any rashes, lesions, medications, hair loss, or nail changes.
Environmental/occupational hazards affecting skin.
Infants, Children, & Aging Adults: Additional considerations:
Birthmarks or changes in skin color since birth.
Rashes, sores, or diaper rash.
Habits like nail-biting.
Delays in wound healing in aging adults or changes in feet (bruises, trauma).
Objective Data Collection
Preparation:
Assure all necessary equipment: strong direct lighting, gloves, penlight, centimeter ruler, etc.
Examination:
Skin assessment should be integrated throughout the physical examination.
Inspect intertriginous areas (skinfolds) thoroughly.
Always inspect the feet, toenails, and spaces between toes.
Focus assessment on skin as a whole.
Inspection and Palpation of Skin
Color Examination:
Observe general pigmentation, moles, freckles.
Widespread color changes (pallor, erythema, cyanosis, jaundice).
Note if changes are transient or pathological.
Temperature:
Palpate using the backs of hands; should be warm and equal bilaterally (hands and feet may be cooler in a cool environment).
Observe for hypothermia or hyperthermia conditions.
Moisture: Check for diaphoresis and dehydration.
Texture: Normal skin texture should be smooth, firm, and even.
Thickness: Observe for any callus formations or thickened areas.
Edema: Assess for fluid accumulation in interstitial spaces.
Mobility and Turgor: Test skin elasticity by pinching.
Vascularity or Bruising: Check for presence of tattoos and/or variations.
Lesions: If present, note characteristics:
Color, elevation, shape, size, location, distribution, exudate color, and odor.
Inspection of Hair
Color: Determined by melanin production.
Texture: Ranges from fine to thick, straight to curly; affected by hair care products.
Hair Distribution: Use Tanner staging to identify gender patterns.
Lesions: Check scalp by sectioning hair.
Inspection of Nails
Shape and Contour:
Profile sign: Angle of the nail base should be about 160 degrees.
Consistency: Should be smooth, regular, and uniform in thickness without brittleness.
Color: Nails should be translucent with a pink nail bed.
Capillary Refill: Indicate peripheral circulation status; depress nail edge to blanch and note color return.
Education and Health Promotion
Teaching Skin Self-Examination:
Use the ABCDEF Rule to detect suspicious lesions:
A: Asymmetry
B: Border irregularity
C: Color variations
D: Diameter greater than 6 mm
E: Elevation or evolution
F: Funny looking—"ugly duckling"—different from others.
Notable Skin Conditions and Lesions
Developmental Changes in Skin Color
Infants: General pigmentation, Mongolian spots, café-au-lait spots, etc.
Children: Conditions like erythema toxicum, acrocyanosis, etc.
Adolescents: Acne and changes related to hormone levels.
Aging: Skin color changes, development of senile lentigines and keratoses.
Primary Skin Lesions
Macules: Flat, circumscribed, less than 1 cm.
Papules: Thicker surface elevation caused by epidermis thickening.
Patches: Larger macules greater than 1 cm.
Plaques: Coalescent papules wider than 1 cm.
Nodules: Solid, elevated lesions greater than 1 cm.
Wheals: Raised, transient lesions due to edema.
Tumors: Larger lesions that may be benign or malignant.
Urticaria: Extensive wheals that cause pruritus.
Vesicles: Elevated cavities containing fluid (blisters).
Cysts: Encapsulated fluid-filled cavities.
Bullae: Larger vesicles, greater than 1 cm.
Pustules: Contain pus, elevated and circumscribed.
Secondary Skin Lesions
Crust: Thickened dried exudate on the skin surface.
Scale: Compact flakes of desiccated skin due to shedding.
Fissures: Linear cracks with abrupt edges.
Erosions: Shallow scooped-out depressions.
Ulcers: Deeper lesions extending into dermis that may bleed.
Excoriations: Superficial, self-inflicted abrasions.
Scars: Permanent fibrotic changes post-healing.
Atrophic Scars: Thinned tissue resulting from loss of material.
Lichenifications: Thickened skin due to prolonged scratching.
Keloids: Excess scar tissue formation beyond injury site.
Stages of Pressure Injuries (Stage I-IV)
Stage I: Non-blanchable erythema.
Stage II: Partial-thickness skin loss.
Stage III: Full-thickness skin loss.
Stage IV: Full-thickness skin and tissue loss.
Deep Tissue Pressure Injury (DTPI): Caused by medical devices.
Common Skin Conditions Across Life Stages
Children: Diaper dermatitis, impetigo, eczema.
Adults: Primary contact dermatitis, tinea infections, various forms of cancer.
Abnormal Hair Conditions
- Conditions: Includes toxic alopecia, tinea capitis, traction alopecia, and folliculitis barbae.
Abnormal Nail Conditions
Conditions: Include Beau's lines, onychomycosis, and habit-tic dystrophy.