Foundational skin information 
The integumentary system consists of the skin, hair, nails, glands, and sensory receptors. It serves as the first line of defense against injury, infection, and dehydration while regulating temperature and sensation. Below are the layers of skin and their descriptions:
 
Epidermis (outermost layer) 
Avascular (no blood vessels) 
Composed of keratinized stratified squamous epithelium 
Key Cells:
Keratinocytes – strength & waterproofing (keratin production) 
Melanocytes – pigmentation & ultraviolet light protection 
Langerhans Cells – immune defense 
Merkel Cells – touch sensation 
 
 
Epidermal Layers (Deep → Superficial)
Stratum basale (Germinativum) – active mitosis, melanocytes present 
Stratum spinosum – thickest layer, desmosomes for strength 
Stratum granulosum - keratinization begins 
Stratum lucidum – only in thick skin (palms/soles) 
Stratum corneum – dead keratinized cells (barrier layer) 
 
 
 
Dermis (middle layer) 
Vascularized, supplies nutrients to the epidermis 
Contains:
Blood vessels 
Nerve endings 
Hair follicles 
Sweat & sebaceous glands 
Collagen & elastin fibers (structural support) 
 
 
Dermal layers:
Papillary layer – loose connective tissue, fingerprints, touch receptors 
Reticular layer – dense irregular connective tissue, deep pressure receptors 
 
 
 
Hypodermis (subcutaneous tissue - deepest layer) 
Composed of: fat (adipose tissue), connective tissue 
Function: insulation, energy storage, shock absorption 
 
Related to skin 
Hair – protects against UV, insulates scalp 
Nails – keratinized structures for protection & dexterity 
Sebaceous (Oil) glands – secrete sebum (moisturizes & protects skin 
Sweat glands – regulate temperature & remove waste 
Eccrine glands – watery sweat, found everywhere 
 
Wound healing phases 
Inflammatory phase 
Initiated immediately and lasts 3-4 days 
Marked by hemostasis (stopping bleeding) and phagocytosis (removal of debris and pathogens) 
 
Proliferative phase 
Lasts until day 21 post-injury 
Collagen formation: A whitish protein substance that adds to the tensile strength of the wound 
Eschar formation may occur 
 
Maturation phase 
Begins at day 21 and lasts up to 1-2 years 
Leads to scar formation 
 
Types of healing 
Primary intention (first intention) 
Tissue surfaces are closed with minimal tissue loss 
Example: Surgical incision 
 
Secondary intention 
Extensive tissue loss prevents edges from being approximated 
Example: Pressure ulcer 
Longer repair time, increased scarring, and higher infection risk 
 
Tertiary intention healing (delayed closure) 
Wound is left open for a period before closure 
Example: Abdominal wound left open for drainage before later closure 
 
Classification of wound drainage 
Serous - Clear to brownish fluid from the serum portion of blood 
Sanguineous - Bright red, bloody drainage 
Serosanguineous - Pinkish drainage, a mix of blood and serum 
Purulent - Thick, yellow or yellow-green pus, indicating infection 
 
How to measure wounds accurately 
Measuring wounds is essential for assessing healing progress and treatment effectiveness. Proper wound measurement includes length, width, depth, and any tunneling or undermining. Below are the tools and steps for how to measure a wound
 
Tools needed for wound measurement 
Disposable ruler (centimeters or millimeters) 
Sterile cotton-tipped applicator (for depth) 
Wound probe (for tunneling or undermining) 
Gloves (to maintain infection control) 
Transparent film grid (optional for tracing irregular shapes) 
 
Step-by-step wound measurement 
Measuring length and width 
Patient positioning: Ensure the patient is in the same position each time for consistency 
Use a ruler: Place a disposable ruler over the wound 
Length measurement: Measure from the longest point head-to-toe (cephalad to caudal) 
Width measurement: Measure perpendicular to the length, at the widest point from side to side 
Documentation format: Length × Width (e.g., 5.2 cm × 3.4 cm) 
 
Measuring wound depth 
Insert a sterile cotton-tipped applicator into the deepest part of the wound 
Mark the level where it meets the wound edge (this should be perpendicular to the to the cotton applicator) 
Remove and measure against a ruler 
Example documentation: Depth = 0.8 cm 
 
Definitions 
Tunneling 
Tract extending deeper into tissue 
Undermining 
Cavity or space under wound edges 
 
Steps for measuring tunneling and undermining 
Insert a sterile probe into the suspected tunnel/undermined area 
Measure using a ruler 
Use the clock method to describe location (e.g., “Tunneling at 3 o’clock position, depth 1.5 cm”) 
 
Additional documentation details 
Shape & Edges: Irregular, round, oval, jagged 
Tissue Type: Granulation, slough, eschar 
Exudate: Amount (none, scant, moderate, heavy) & type (serous, purulent, sanguineous) 
Periwound Skin: Erythema, edema, maceration, induration 
 
Types of dressing 
Gauze dressings 
Names: Sterile gauze, non-sterile gauze, impregnated gauze 
Indications:  Used for wounds with moderate to heavy exudate, surgical wounds, and packing deep woundsContraindications : Not ideal for dry wounds (can cause adherence and delay healing) 
Transparent film dressings 
Names: Tegaderm, Opsite, Bioclusive 
Indications : Superficial wounds, abrasions, and partial-thickness wounds with minimal exudate; also used for IV sitesContraindications : Should not be used on heavily exudating wounds or infected wounds 
Hydrocolloid dressings 
Names: Duoderm, Comfeel, Tegasorb 
Indications:  Moderate exudating wounds, pressure ulcers, and venous leg ulcers. Helps maintain a moist wound environment.Contraindications:  Not suitable for infected wounds or wounds with heavy exudate. 
Hydrogel dressings 
Names: IntraSite Gel, Aquaform, Vigilon 
Indications : Dry wounds, burns, painful wounds, and wounds with necrotic tissue (autolytic debridement).Contraindications:  Should not be used on heavily exudating wounds as it can cause maceration. 
Foam dressings 
Names: Allevyn, Mepilex, Lyofoam 
Indications:  Moderate to heavily exudating wounds, pressure ulcers, and diabetic foot ulcers. Provides cushioning.Contraindications : Not ideal for dry wounds or wounds with minimal exudate. 
Alginate dressings 
Names: Kaltostat, Sorbsan, Algicell 
Indications:  Heavy exudating wounds, infected wounds, and wounds with tunneling. Derived from seaweed, absorbs large amounts of fluid.Contraindications:  Not recommended for dry wounds or wounds with minimal exudate. 
Collagen dressings 
Names: Promogran, Fibracol, Biostep 
Indications:  Chronic non-healing wounds, pressure ulcers, and wounds with granulation tissue. Encourages new tissue growth.Contraindications : Not for dry wounds or wounds with eschar. Avoid in patients with collagen allergies. 
Antimicrobial dressings 
Names: Silvercel, Acticoat, Iodosorb 
Indications:  Infected wounds, burns, surgical wounds at risk of infection. Contains silver or iodine to reduce bacterial load.Contraindications:  Avoid in patients allergic to silver or iodine. Not recommended for long-term use due to potential cytotoxicity. 
Types of debridement 
Debridement is the removal of slough or eschar/necrotic tissue from a wound base. The goal is to remove these unhealthy wound products and leave only granulation tissue.
 
Definitions 
Slough 
Soft, yellow or white, stringy or thick substance that overlays the wound bed, composed of dead cells, fibrin, and other substances, hindering healing and increasing infection risks 
Eschar/necrotic tissue 
Hardened, dry, black or brown dead tissue that forms a scab-like covering over deep wounds, such as severe burns or ulcers, and can impede healing 
Granulation tissue 
New, highly vascular connective tissue that forms during the wound healing process, filling in the wound bed and providing a scaffold for new blood vessels and tissue to grow. 
 
Autolytic debridement 
Definition: Uses the body’s own enzymes and moisture to break down necrotic tissue. 
Methods: Hydrocolloid, hydrogel, or transparent film dressings. 
Indications:
Wounds with necrotic tissue (eschar or slough). 
Patients who cannot tolerate more aggressive debridement. 
Minimal to moderate exudating wounds. 
 
 
Contraindications:
Infected wounds. 
Heavily exudating wounds. 
 
 
 
Mechanical debridement 
Definition: Uses physical forces to remove necrotic tissue. 
Methods:
Wet-to-dry dressings (gauze applied wet and removed dry). 
Hydrotherapy (whirlpool). 
Pulsed lavage (pressurized irrigation). 
 
 
Indications:
Moderate to heavily necrotic wounds. 
Wounds with thick, adherent slough or debris. 
 
 
Contraindications:
Painful wounds. 
Granulating wounds (can damage healthy tissue). 
 
 
 
Enzymatic debridement 
Definition: Uses topical enzymatic agents to break down necrotic tissue. 
Methods: Application of collagenase (e.g., Santyl). 
Indications:
Wounds with thick, adherent necrotic tissue. 
Patients unable to tolerate surgical or sharp debridement. 
 
 
Contraindications:
Infected wounds without antibiotic coverage. 
Clean wounds with no necrotic tissue. 
 
 
 
Sharp debridement 
Definition: Uses scalpels, scissors, or forceps to remove necrotic tissue manually. 
Indications:
Wounds with extensive necrosis or thick eschar. 
Infected wounds requiring immediate removal of necrotic tissue. 
 
 
Contraindications:
Bleeding disorders or anticoagulated patients. 
Poor vascular supply (risk of delayed healing). 
 
 
 
Surgical debridement 
Definition: Performed by a surgeon in an operating room to remove large amounts of necrotic tissue. 
Indications:
Deep wounds with extensive necrosis. 
Life-threatening infections (e.g., necrotizing fasciitis). 
Chronic non-healing wounds requiring aggressive intervention. 
 
 
Contraindications:
Patients who are medically unstable for surgery. 
 
 
 
Biological (maggot) debridement 
Definition: Uses sterile maggots (larvae of Lucilia sericata) to digest necrotic tissue and bacteria. 
Indications:
Chronic, non-healing wounds with necrotic tissue. 
Infected wounds (maggots secrete antimicrobial enzymes). 
 
 
Contraindications:
Patient refusal. 
Allergies to fly larvae or materials used in dressing containment. 
 
 
 
Wound classifications by etiology 
Arterial wounds 
Cause: Reduced arterial blood supply leading to ischemia and necrosis.
Characteristics:
Location: Toes, lateral malleolus, dorsum of the foot, distal lower extremities. 
Appearance: Punched-out, deep with well-defined edges. Wound Bed: Pale, necrotic, minimal granulation tissue. 
Drainage: Minimal (often dry ).Surrounding Skin: Cool, shiny, thin, hair loss, pallor with elevation, dependent rubor. 
Pain: Severe, worsens with elevation, relieved in dependent position. Pulses: Diminished or absent. 
Risk Factors: Peripheral arterial disease (PAD), smoking, diabetes, hypertension. 
 
Grading 
Partial thickness- depth only extends through epidermis and parts of dermis 
Full thickness- depth extends to subcutaneous tissue 
 
Venous wounds 
Cause: Venous insufficiency leading to fluid retention, inflammation, and skin breakdown.
Characteristics: 
Location: Medial malleolus, lower leg (gaiter region). 
Appearance: Shallow, irregular borders, large wound area. Wound Bed: Granular, red with yellow fibrinous tissue. 
Drainage: Moderate to heavy (wet wound) .Surrounding Skin: Edema, hemosiderin staining (brown discoloration), lipodermatosclerosis (thickened skin). 
Pain: Mild to moderate, relieved by elevation. Pulses: Present but may be difficult to palpate due to edema. 
Risk Factors: Chronic venous insufficiency, varicose veins, obesity, prolonged standing. 
 
Grading 
Partial thickness- depth only extends through epidermis and parts of dermis 
Full thickness- depth extends to subcutaneous tissue 
 
Pressure wounds 
Cause: Prolonged pressure, shear, or friction leading to ischemic damage.
Characteristics: 
Location: Bony prominences (sacrum, heels, ischial tuberosities, greater trochanter) .Appearance: Varies by stage, from non-blanchable redness to deep tissue damage. 
Drainage: Variable (depends on stage and infection presence). 
Surrounding Skin: May show maceration, erythema, or induration. 
Pain: Variable (more in early stages, less in advanced necrotic ulcers). 
Risk Factors: Immobility, malnutrition, incontinence, neuropathy.  
Grading: national pressure injury staging 
Stage 1:  Non-blanchable erythema, intact skin.Stage 2:  Partial-thickness skin loss (blister or shallow ulcer).Stage 3:  Full-thickness skin loss with visible fat, but no bone/muscle.Stage 4:  Full-thickness with exposed bone, muscle, or tendon.Unstageable:  Wound covered by necrotic tissue, depth unclear.Deep tissue injury:  Intact or non-intact skin with persistent non-blanchable deep red, maroon, or purple discoloration. 
Stages of pressure injury Diabetic wounds 
Cause: Peripheral neuropathy, pressure, and poor circulation due to diabetes.
Characteristics: 
Location: Plantar surface of foot, metatarsal heads, heels, toes. Appearance: Punched-out, round, deep, with well-defined edges. Wound Bed: Pale or granulating tissue, may have necrosis. 
Drainage: Minimal unless infected .Surrounding Skin: Calloused, dry, cracked, loss of protective sensation (neuropathy). 
Pain: Typically painless due to neuropathy. Pulses: May be present or diminished (if arterial disease is also present). 
Risk Factors: Diabetes, poor glycemic control, loss of sensation, foot deformities. 
 
Grading: wagner classification for diabetic foot ulcers 
Grade 0:  Intact skin with high risk (calluses, foot deformities).Grade 1:  Superficial ulcer (partial/full-thickness skin loss).Grade 2:  Ulcer extending to tendon, bone, or capsule.Grade 3:  Deep ulcer with abscess, osteomyelitis.Grade 4:  Localized gangrene.Grade 5:  Extensive gangrene of foot requiring amputation. 
Burns 
Causes: Thermal, friction, electrical, chemical, radiation
The presentation of burns are determined by the classification. See below:
Superficial (First-degree burn) 
Layers Affected: Epidermis only 
Appearance: Red, dry, no blisters 
Pain Level: Mild to moderate 
Healing Time: 3-7 days without scarring 
Example: Sunburn 
 
Partial-thickness (second-degree burn) 
a. Superficial Partial-Thickness 
Layers Affected: Epidermis + upper dermis 
Appearance: Red, moist, blisters present 
Pain Level: Very painful (nerve endings intact) 
Healing Time: 10-21 days, minimal to no scarring 
 
b. Deep Partial-Thickness 
Layers Affected: Epidermis + deeper dermis 
Appearance: Mottled red/white, sluggish blanching 
Pain Level: Less painful (nerve endings damaged) 
Healing Time: 3-6 weeks, scarring likely 
 
Full-Thickness (third-degree burn) 
Layers Affected: Epidermis + entire dermis (may extend to subcutaneous tissue) 
Appearance: White, leathery, charred, dry 
Pain Level: Painless (nerve endings destroyed) 
Healing Time: Requires skin grafting, significant scarring 
 
Subdermal (fourth-degree burn) 
Layers Affected: Epidermis, dermis, fat, muscle, and bone 
Appearance: Black, charred, necrotic tissue 
Pain Level: Painless (complete nerve destruction) 
Healing Time: Requires surgical intervention, amputation possible 
 
Use of grafts for burns 
Grafts are required for deep partial thickness and full thickness burns to aid in re-epithelization. Grafts can be taken from different areas of the body, another individual’s body, or another species. Below are different types of grafts:
 
Autografts: taken from the individual 
Allografts:taken from cadavers 
Xenografts: taken from another species (i.e. pig, cow) 
 
Interventions for burns 
The specific interventions for burns are determined by the depth of the wound and/or the level of tissue damaged. See below for specifics regarding interventions:
 
First-degree burns 
Cool the burn with cool water. 
Apply over-the-counter pain relievers, such as NSAIDs or acetaminophen. 
Use aloe vera gel or petroleum jelly to soothe the burn. 
 
Second-degree burns 
In addition to the above, apply a topical antibiotic cream, such as bacitracin or neomycin. 
Cover the burn with a non-stick dressing. 
Use silver sulfadiazine cream to prevent infection. 
 
Definitions 
Bacitracin 
Stops the growth of bacteria for wounds 
Neomycin 
Functions by inhibiting bacterial protein synthesis, resulting in a bactericidal effect primarily against gram-negative bacteria 
Silver sulfadiazine 
Prevents and treats infections in second and third-degree burns, and sometimes for other skin infections 
Mafenide acetate 
Acts by reducing the bacterial population present in the burn tissue and promotes healing of deep burns 
 
Third-degree burns 
Intravenous fluids and pain relievers 
Antibiotic therapy 
Topical dressings, such as mafenide acetate or silver sulfadiazine 
Surgery may be necessary to remove the burned skin and graft new skin. 
 
Other medications 
Corticosteroids may be used to reduce inflammation. 
Antihistamines may be used to relieve itching. 
Sedatives may be used to manage pain and anxiety. 
 
Rule of Nines for burn assessment 
The Rule of Nines is a quick method to estimate the total body surface area (TBSA) affected by burns. It differs for adults and children due to variations in body proportions.
Rule of Nines for adults 
In adults, the body is divided into sections, each representing 9% or a multiple of 9% of the total body surface area:
Body Part
 
Percentage (%) of TBSA
 
 
Head & Neck
 
9% (4.5% front, 4.5% back)
 
 
Each Arm
 
9% (4.5% front, 4.5% back)
 
 
Each Leg
 
18% (9% front, 9% back)
 
 
Anterior Torso
 
18%
 
 
Posterior Torso
 
18%
 
 
Perineum (Genital Area)
 
1%
 
 
Example: A burn covering the entire front of one leg and half the anterior torso would be 9% + 9% = 18% TBSA.
 
Rule of Nines for children 
Children have a larger head-to-body ratio, so the Rule of Nines is adjusted:
Body Part
 
Percentage (%) of TBSA
 
 
Head & Neck
 
18% (9% front, 9% back)
 
 
Each Arm
 
9% (4.5% front, 4.5% back)
 
 
Each Leg
 
14% (7% front, 7% back)
 
 
Anterior Torso
 
18%
 
 
Posterior Torso
 
18%
 
 
Perineum (Genital Area)
 
1%
 
 
Example: A child with burns covering the entire head and one arm would have 18% + 9% = 27% TBSA.
 
Other common skin conditions 
Impetigo 
Impetigo is a bacterial skin infection caused by Staphylococcus aureus or Streptococcus pyogenes. It is highly contagious and commonly affects children. The hallmark feature is honey-colored, crusted lesions that typically appear around the mouth, nose, and hands. Mild itching may be present, but systemic symptoms like fever are rare. Since impetigo is superficial, it does not cause deep tissue damage and is easily treatable with antibiotics.
Cellulitis 
Cellulitis is a bacterial skin infection that occurs in the deeper layers of the skin and subcutaneous tissue. It is most commonly caused by Staphylococcus aureus or Streptococcus pyogenes. Unlike impetigo, cellulitis presents with diffuse redness, warmth, swelling, and pain, and it may be accompanied by systemic symptoms such as fever, chills, and malaise. It commonly affects the lower extremities but can occur anywhere. Cellulitis can spread quickly and requires antibiotics, and in severe cases, hospitalization may be necessary.
Herpes Zoster (Shingles) 
Herpes zoster, or shingles, is a viral infection caused by the reactivation of the varicella-zoster virus (the same virus that causes chickenpox). It presents as a painful, blistering rash that follows a dermatomal pattern—meaning it is limited to one side of the body along a nerve path. Before the rash appears, individuals may experience burning, tingling, or flu-like symptoms. Unlike impetigo and cellulitis, herpes zoster is not a bacterial infection and requires antiviral treatment. A significant complication is post-herpetic neuralgia, which can cause chronic nerve pain even after the rash has resolved.
Dermatitis (Eczema) 
Dermatitis is a non-infectious inflammatory skin condition caused by an immune response to allergens, irritants, or chronic skin sensitivity. It presents as red, dry, scaly, and itchy skin and is often associated with pruritus (intense itching). Unlike the other conditions, dermatitis is not contagious and does not involve bacterial or viral pathogens. Common triggers include allergens, soaps, stress, and climate changes. Treatment involves moisturizers, corticosteroids, and avoiding triggers.
Psorasis 
Psoriasis is a chronic autoimmune skin condition that causes rapid skin cell turnover, leading to the buildup of thick, scaly plaques on the skin. It is characterized by red, inflamed patches with silvery-white scales, often appearing on the scalp, elbows, knees, and lower back. The condition is not contagious and can be triggered by stress, infections, medications, and environmental factors. Psoriasis is associated with immune system dysfunction, specifically involving T-cells and inflammatory cytokines. It can also be linked to psoriatic arthritis, which affects the joints. Treatment includes topical steroids, phototherapy, and systemic immunosuppressants.
Sclerederma 
Scleroderma is a chronic autoimmune connective tissue disease characterized by abnormal collagen deposition, leading to skin thickening, fibrosis, and vascular dysfunction. It can affect the skin, blood vessels, and internal organs, including the lungs, heart, kidneys, and gastrointestinal tract.
There are two main types:
Localized Scleroderma – Primarily affects the skin and underlying tissues, often in morphea or linear forms. 
Systemic Sclerosis (Systemic Scleroderma) – Involves widespread fibrosis affecting the skin and internal organs. 
 
Common symptoms include tight, hard skin, Raynaud’s phenomenon, joint pain, and digestive issues. The exact cause is unknown, but it is believed to involve immune system dysfunction and genetic/environmental factors. There is no cure, but treatment focuses on managing symptoms and slowing disease progression with immunosuppressants, vasodilators, and physical therapy.