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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
Key points
- Category 1: non-blanchable erythema. Cat 2: partial-thickness/blister. Cat 3: full-thickness skin loss. Cat 4: bone/tendon visible
- Common sites: sacrum, heels, ischial tuberosities, greater trochanters
- Risk assessment: Waterlow score — assess on admission and regularly
- Prevention is paramount: 2-hourly repositioning, pressure-redistributing devices, nutrition
- Management: remove pressure, appropriate dressings, treat infection, nutrition optimisation
Overview
Pressure ulcers are localised tissue damage from sustained pressure exceeding capillary closing pressure (~32 mmHg) over bony prominences. Contributing factors include shear, friction, moisture, and poor nutrition. Prevention through risk assessment and proactive intervention is the cornerstone.
Epidemiology
Prevalence ~5-10% of UK hospital inpatients. Cost to NHS estimated at £1.4-2.1 billion/year. Cat 3/4 ulcers are classified as potential never events. More common in elderly, immobile, critical care, and spinal cord injury patients.
Clinical Features
Symptoms
Category 1: non-blanchable erythema of intact skin
Category 2: partial-thickness loss — shallow ulcer or intact blister
Category 3: full-thickness skin loss, fat visible, no bone/tendon
Category 4: full-thickness with bone/tendon/muscle exposed
Signs of wound infection: increasing pain, erythema, purulent exudate
Signs
Sacrum, heels, ischial tuberosities — commonest sites
Non-blanchable erythema (press 3 seconds, erythema persists)
On darker skin: assess warmth, induration, colour change (purple/blue)
Investigations
First-line
Clinical assessmentEPUAP category, wound dimensions, wound bed assessment
Risk assessmentWaterlow score on admission and regularly thereafter
Second-line
Wound swabIf clinical infection — MC&S for antibiotic guidance
BloodsAlbumin (nutrition), HbA1c, CRP if indicated
Specialist
MRIIf osteomyelitis suspected in deep Cat 4 ulcers
1
Prevention
- Waterlow score on admission
- 2-hourly repositioning for bed-bound
- Alternating pressure mattress, foam cushions, heel offloading
- Daily skin inspection over bony prominences
- Optimise nutrition — dietitian referral
- Continence care, barrier creams
2
Wound management
- Remove/redistribute pressure
- Wound debridement (autolytic, sharp)
- Appropriate wound dressings based on characteristics
3
Complications
- Wound infection: topical antimicrobial dressings; systemic antibiotics for cellulitis/sepsis
- Pain management
- Nutritional support: high-protein supplements
Complications
- Wound infection and sepsis
- Osteomyelitis: Deep infection in Cat 4
- Marjolin's ulcer: SCC in chronic wounds (rare)
UKMLA Exam Tips
- 1Cat 1 = non-blanchable erythema. Cat 4 = bone/tendon visible
- 2Waterlow score: UK standard pressure ulcer risk assessment
- 3Most common site: sacrum
- 4Prevention: repositioning + pressure-relieving devices + nutrition
- 5Cat 3/4 in hospital = potential never event — root cause analysis required
- 6On darker skin: non-blanchable erythema may appear purple/blue, not red
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