Pathophysiology · Musculoskeletal and Integumentary Pathophysiology
Skin Disorders
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In 30 seconds
This section covers common skin (integumentary) disorders — infections, inflammatory conditions (like eczema and psoriasis), burns, pressure injuries, and skin cancer — rounding out pathophysiology with the body's largest organ.
Why this matters
The skin is the body's protective barrier, and its disorders are extremely common. Pressure injuries, burns, and wound care are core nursing responsibilities, and recognizing skin cancer and infections is important for patient health.
The college version
Core Explanation
Skin's role (brief review). The skin (integumentary system) is the body's largest organ and its first line of defense — a protective barrier against pathogens, injury, and water loss, plus roles in temperature regulation, sensation, and vitamin D production (recall A&P). When the skin's barrier is broken or diseased, protection is compromised.
Infections and inflammatory conditions. Common skin problems include:
- Infections — bacterial (e.g., cellulitis, a spreading skin infection), fungal (e.g., ringworm, athlete's foot), and viral (e.g., warts, shingles). Broken skin increases infection risk (recall Microbiology).
- Inflammatory/immune conditions — e.g., eczema (atopic dermatitis), causing itchy, inflamed skin; psoriasis, an immune-related condition with thickened, scaly patches (related to excessive skin cell turnover); and contact dermatitis (reaction to an irritant/allergen).
Burns. Burns are injuries to the skin (and possibly deeper tissue) from heat, chemicals, electricity, or radiation. They're classified by depth:
- Superficial (first-degree) — affects only the outer layer (epidermis); red, painful (like a mild sunburn).
- Partial-thickness (second-degree) — affects epidermis and part of the dermis; blisters, very painful.
- Full-thickness (third-degree) — destroys the full skin thickness (and may involve deeper tissue); may appear white/charred and be numb (nerve damage).
Severe/extensive burns are emergencies — they cause fluid loss (risk of shock), infection risk (loss of the protective barrier), and temperature regulation problems. Burn care involves fluids, infection prevention, and wound care.
Pressure injuries (pressure ulcers). Pressure injuries ("bedsores") are areas of skin/tissue damage caused by prolonged pressure, usually over bony areas (e.g., heels, hips, sacrum), which reduces blood flow (ischemia) and damages tissue (recall ischemia). They're a major concern in immobile, bedridden patients. Prevention is a key nursing responsibility: repositioning regularly, keeping skin clean and dry, good nutrition, and using pressure-relief supports. Pressure injuries are staged by severity.
Skin cancer. Skin cancer is common and largely related to UV (sun/tanning) exposure (recall carcinogenesis). Main types:
- Basal cell and squamous cell carcinomas — common, usually less aggressive (though squamous can spread).
- Melanoma — less common but more dangerous (can metastasize); arises from pigment cells. Warning signs use the ABCDE rule for moles: Asymmetry, Border irregularity, Color variation, Diameter (large), Evolving (changing).
Prevention: sun protection (sunscreen, avoiding excessive UV) and early detection (checking skin/moles) — highly effective.
How It Works
Skin disorders:
Skin = largest organ, protective barrier (+ temperature, sensation, vitamin D); broken barrier → risk
INFECTIONS: bacterial (cellulitis), fungal (ringworm), viral (warts, shingles)
INFLAMMATORY/IMMUNE: eczema (itchy), psoriasis (scaly, immune/↑turnover), contact dermatitis
BURNS (by depth): superficial (1st, epidermis, red) → partial-thickness (2nd, blisters, painful) → full-thickness (3rd, all layers, may be numb)
severe = EMERGENCY: fluid loss/shock, infection, temperature problems
PRESSURE INJURIES = prolonged pressure over bony areas → ischemia → tissue damage (immobile patients)
PREVENT: reposition, clean/dry skin, nutrition, pressure relief (key nursing role)
SKIN CANCER (UV-related): basal cell + squamous cell (common) | MELANOMA (dangerous, metastasizes) — ABCDE moles
prevent: sun protection + early detectionImportant Relationships and Comparisons
| Burn depth | Layers | Appearance |
|---|---|---|
| Superficial (1st) | Epidermis | Red, painful |
| Partial-thickness (2nd) | Epidermis + part of dermis | Blisters, very painful |
| Full-thickness (3rd) | Full skin (+ deeper) | White/charred, may be numb |
| Skin cancer | Note |
|---|---|
| Basal/squamous cell | Common, usually less aggressive |
| Melanoma | Less common, more dangerous (ABCDE) |
High-Yield Pre-Nursing Connections
Pressure injury prevention (repositioning, skin care, nutrition) is a core nursing responsibility for immobile patients — connecting to ischemia and wound healing. Burn care (fluids, infection prevention, wound care) addresses fluid loss, infection, and temperature — severe burns are emergencies. Skin cancer prevention (sun protection) and early detection (ABCDE) tie to carcinogenesis and prevention. Cellulitis and other infections require recognition and treatment. The skin as a barrier underlies infection control and overall protection.
Quick Recap
- The skin is the body's largest organ and protective barrier; when broken or diseased, protection is compromised.
- Common problems include infections (bacterial like cellulitis, fungal, viral) and inflammatory conditions (eczema, psoriasis, contact dermatitis).
- Burns are classified by depth (superficial → partial-thickness → full-thickness); severe burns are emergencies (fluid loss, infection, temperature problems).
- Pressure injuries result from prolonged pressure → ischemia (a key nursing prevention focus); skin cancer (esp. melanoma, watched via ABCDE) is largely UV-related and prevented with sun protection and early detection.
Common Confusions
- Burn depth: superficial (epidermis) → partial-thickness (blisters) → full-thickness (all layers, may be numb).
- Pressure injuries come from prolonged pressure → ischemia, especially over bony areas.
- Melanoma is the most dangerous skin cancer (use ABCDE for moles).
- The skin is a protective barrier — broken skin raises infection risk.
Eli explains
The same idea, in plain words
Explain it like I’m 10
Simple idea
Your skin is your body's protective shield. It can get infected, inflamed (like eczema), burned, develop pressure sores from lying still too long, or grow skin cancer (mostly from sun). Nurses do a lot of skin and wound care.
Analogy
Think of your skin as the protective outer wall around the "castle" of your body — it keeps germs out, holds water in, and helps control temperature. When that wall is damaged, problems follow. Infections happen when germs get in (like cellulitis, a spreading bacterial infection). Inflammatory conditions like eczema (itchy, irritated skin) and psoriasis (thick, scaly patches) are the wall getting inflamed. Burns are damage from heat (or chemicals/electricity), and they're rated by how deep they go: first-degree is just the surface (red, like a sunburn), second-degree goes deeper with blisters, and third-degree burns through all the layers (and can even feel numb because the nerves are damaged) — bad burns are emergencies because you lose fluid and your protective barrier. Pressure injuries (bedsores) happen when someone lies in one position too long, and the constant pressure cuts off blood flow to the skin over bony spots (like heels and hips), damaging it. And skin cancer — mostly caused by too much sun (UV) — is very common; the most dangerous type is melanoma, which we watch for using the ABCDE rule for suspicious moles.
What is actually happening
Skin and wound care is a huge, hands-on part of nursing. One of the most important jobs is preventing pressure injuries in patients who can't move much — by repositioning them regularly, keeping their skin clean and dry, and ensuring good nutrition (this connects to ischemia and wound healing you learned earlier). Burn care is intensive: managing fluid loss (to prevent shock), preventing infection (since the barrier is gone), and caring for wounds. Nurses also promote skin cancer prevention — teaching sun protection — and early detection using the ABCDE mole check, which connects to what you learned about cancer. Recognizing skin infections (like cellulitis) is important too. Since the skin is the body's first defense, taking care of it protects the whole person.
Where the analogy stops
A castle wall is static, but skin is a living, self-repairing organ that heals, senses, regulates temperature, and even makes vitamin D — so caring for it supports far more than just "keeping germs out."
Study tools & related lessonsYou’ll learn to · Related
You’ll learn to
- Review the skin's protective role briefly.
- Describe common skin infections and inflammatory conditions.
- Describe burns and pressure injuries.
- Describe skin cancer and prevention.
Sources & references
- OpenStax, *Anatomy and Physiology 2e*, Chapter 5: The Integumentary System.
- U.S. Centers for Disease Control and Prevention — Skin Cancer; MedlinePlus — Pressure Sores; Burns.
This lesson was adapted from the open educational references above; their licenses and attributions are preserved. See Copyright & Licensing.
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