Topic 3: Assess 3 Dimensions of Severity

A practical severity assessment can be organized around 3 complementary dimensions.

1. Inflammatory activity

Evaluate the number and distribution of:

• Inflammatory nodules
• Abscesses
• Draining tunnels
• Anatomic regions involved

Also consider whether lesions are persistent, recurrent, or increasing between visits. A patient may have few lesions at the appointment but report frequent or nearly continuous activity between visits. Patient photographs, prior documentation, and a careful flare history may provide a more representative view.

2. Structural damage

Look and palpate for:

• Draining or nondraining tunnels
• Hypertrophic, fibrotic, or rope-like scarring
• Tissue distortion
• Contractures
• Restricted movement
• Repeated lesions occurring within previously scarred areas

Tunnels are particularly important because they indicate disease extending beneath the visible surface. One inflamed tunnel may be clinically meaningful even when the total visible lesion count is low. A 2026 expert framework proposed that one inflamed draining or nondraining tunnel can identify moderate disease and support consideration of prompt treatment.⁵

3. Patient-reported burden

Ask about:

• Current and worst pain
• Flare frequency and duration
• Drainage, odor, and dressing requirements
• Pruritus and sleep disturbance
• Difficulty walking, sitting, exercising, or raising an arm
• Missed work or school
• Sexual health and relationships
• Embarrassment, isolation, anxiety, or low mood
• Response to previous treatments

Patient-reported burden does not always correlate closely with lesion count. A systematic review found that HS negatively affects physical, psychological, sexual, and work-related aspects of patients’ lives. Pain was the most frequently evaluated symptom, and moderate-to-severe HS was associated with moderate to high pain levels.⁶