How to Chart a Pyoderma Gangrenosum Lesion
Document pyoderma gangrenosum lesions by recording their morphology (papule, pustule, or ulcer), location, size in centimeters, border characteristics (violaceous/undermined edges), number of lesions, presence of pathergy, and associated systemic symptoms—using standardized descriptive terminology that captures disease progression and treatment response.
Essential Documentation Elements
Initial Lesion Characteristics
When charting PG, begin with the lesion morphology and evolution. PG initially presents as single or multiple erythematous papules or pustules that rapidly progress to deep excavating ulcerations 1, 2. Document:
- Lesion type: Specify whether papule, pustule, or ulcer (noting that pustules typically ulcerate within 4 days of appearing) 3
- Size: Measure ulcer diameter in centimeters (PG ulcers range from 2-20 cm) 2
- Border appearance: Describe the characteristic violaceous (reddish-purple) undermined edges 2
- Base characteristics: Note presence of purulent material (which should be sterile on culture unless secondary infection has occurred) 1
- Depth: Document if deep tissues, tendons, or muscles are exposed 2
Anatomic Location
Record the precise anatomic location, as this has diagnostic and prognostic significance. The most common sites are the shins and areas adjacent to stomas 1, 2. However, PG can occur anywhere on the body, including the genitalia 1. Document whether lesions are on:
- Anterior lower legs (most common site)
- Peristomal areas
- Upper extremities
- Trunk
- Other locations
Number and Distribution
Chart whether lesions are single or multiple. Multiple ulcerations with at least one on an anterior lower leg is a validated diagnostic criterion 3. Document the total number of lesions and their distribution pattern.
Pathergy Documentation
Specifically document any history of trauma preceding the lesion 1, 2. Pathergy (lesion development following trauma) is a characteristic feature of PG and represents one of the validated diagnostic criteria 3. Note:
- Timing of trauma relative to lesion appearance
- Type of trauma (surgical, accidental, minor)
- Location correlation between trauma and lesion
Surrounding Tissue Characteristics
Document the peripheral erythema and tenderness at the ulceration site 3. These features help distinguish PG from other ulcerative conditions and are part of validated diagnostic criteria.
Serial Measurements for Treatment Response
Create a systematic tracking system for disease progression. The evidence supports using a daily blister chart during acute phases 4, which can be adapted for PG ulcer tracking. Document at each visit:
- Change in ulcer size (measure diameter in cm)
- Border characteristics (improvement or worsening of undermining)
- Presence of new lesions
- Pain level (as PG is characteristically extremely painful) 5
- Signs of healing (re-epithelialization, decreased purulent material)
Healing and Scarring Patterns
When lesions heal, document the characteristic "cribriform" or "wrinkled paper" scars 3. This scarring pattern is pathognomonic for PG and represents a validated diagnostic criterion. The presence of these scars at healed ulcer sites should be specifically noted in the medical record.
Clinical Context Documentation
Associated Systemic Conditions
Chart any underlying inflammatory conditions, as 70% of PG cases have associated systemic diseases 2, 6. Specifically document:
- Inflammatory bowel disease (ulcerative colitis or Crohn's disease)
- Inflammatory arthritides (rheumatoid arthritis)
- Hematologic disorders or malignancies
- Other autoimmune conditions
This association is critical because 0.6-2.1% of ulcerative colitis patients develop PG 1, and the presence of IBD or inflammatory arthritis is a validated diagnostic criterion 3.
Treatment Response Documentation
Record response to immunosuppressive therapy within one month of initiation, as decreased ulcer size within this timeframe is a validated diagnostic criterion 3. Document:
- Specific medications used (corticosteroids, cyclosporine, biologics)
- Dosages and duration
- Objective measurement of ulcer size reduction
- Time to initial response
The evidence shows that response rates exceed 90% in patients with PG duration less than 12 weeks, but drop below 50% when disease has been present for more than 3 months 1, 2, making early documentation of treatment response particularly important.
Common Pitfalls to Avoid
Do not document PG lesions as "infected wounds" requiring debridement. The purulent material in PG is characteristically sterile unless secondary infection has occurred 1, 2. Surgical debridement can worsen PG through pathergy 7.
Avoid vague descriptors like "chronic wound" or "non-healing ulcer." Use specific terminology that captures the violaceous undermined borders and rapid progression characteristic of PG 2.
Do not omit pain documentation. PG lesions are characteristically extremely painful 5, 8, and pain level is an important marker of disease activity and treatment response.