Describing an Ulcer Extending into the Dermal Layer
An ulcer that extends just past the first layer of skin (epidermis) into the dermis is described as a partial-thickness ulcer or Stage 2 pressure injury, characterized by partial-thickness loss of dermis presenting as a shallow open ulcer with a viable red-pink wound bed. 1
Anatomical Classification
The skin consists of distinct layers, and ulcer depth terminology is based on which layers are involved:
- Superficial ulcers involve only the epidermis and are located at the epidermal layer 2
- Partial-thickness ulcers extend through the epidermis into the dermis but do not penetrate below the dermal layer 1
- Full-thickness ulcers extend below the dermis into subcutaneous tissue, fascia, muscle, or bone 2, 3
Specific Terminology by Context
Pressure Injuries
For pressure-related ulcers, Stage 2 is the appropriate classification when the ulcer involves partial-thickness loss of dermis, appearing as a shallow open ulcer with a red-pink wound bed without slough 1. This stage specifically indicates damage that has penetrated the epidermis but has not reached subcutaneous fat or deeper structures 4.
Diabetic Foot Ulcers
In diabetic foot ulceration, the International Working Group on the Diabetic Foot (IWGDF) defines an ulcer as superficial when structures below the dermis are not involved 2. The WIfI classification system describes a Grade 1 wound as "small, shallow ulcer(s) on distal leg or foot; no exposed bone, unless limited to distal phalanx" 2.
General Wound Classification
The traditional definition distinguishes ulcers from wounds based on etiology and depth, where ulcers are defined as wounds with "full thickness depth" 5. However, in contemporary practice, partial-thickness lesions extending into but not through the dermis are still classified as ulcers when they demonstrate slow healing tendency 5.
Key Distinguishing Features
When documenting an ulcer that extends into the dermal layer, specify:
- Depth: Partial-thickness, involving dermis but not subcutaneous tissue 1
- Appearance: Typically presents as a shallow crater or open ulcer 1
- Wound bed: Should be viable tissue, red-pink in color if healthy 1
- Absence of deeper structures: No exposed fat, fascia, muscle, tendon, or bone 3, 4
Common Pitfall
Do not confuse partial-thickness dermal ulcers with full-thickness Stage 3 ulcers, which involve subcutaneous tissue and present as deep craters 3. Stage 3 ulcers extend down to but not through underlying fascia and may contain slough 3. The critical distinction is whether subcutaneous fat is visible—if fat is exposed, the ulcer is full-thickness (Stage 3), not partial-thickness 4.