How to Diagnose Hidradenitis Suppurativa
Hidradenitis suppurativa is diagnosed clinically when three consensus criteria are met: (1) typical lesions, (2) typical anatomic locations, and (3) chronic/recurrent course. 1, 2
Diagnostic Criteria
The diagnosis requires all three of the following elements 1:
1. Typical Lesions
Look for any combination of:
- Painful nodules (deep-seated, inflamed)
- Abscesses
- Sinus tracts (tunnels connecting lesions)
- Bridged scars (rope-like fibrotic bands)
- Open comedones (characteristically paired/double-headed)
- Pustules, cysts, or fistulae
2. Typical Anatomic Sites
Disease must involve flexural/intertriginous areas 1, 2:
- Axillae (most common)
- Groin (inguinal region)
- Perineal/perianal region
- Buttocks
- Inframammary folds (under breasts)
- Medial thighs
- Abdominal folds
- Posterior auricular region (behind ears)
3. Chronicity and Recurrence
The disease must be either 1:
- Recurrent: Two or more episodes within 6 months, OR
- Chronic/persistent: Continuous lesions for ≥3 months
Clinical Presentation Details
Patients typically present with 1:
- Post-pubertal onset (second to fourth decades of life)
- Severe pain (often the most debilitating symptom)
- Chronic purulent or serosanguinous discharge
- Persistent malodor
- Pruritus
- Progressive scarring and fibrosis in long-standing disease
No Laboratory Testing Required
Histopathological confirmation is rarely needed 1. HS is a clinical diagnosis based on history and physical examination alone 3. Microbiologic cultures have limited utility, as they typically grow mixed normal flora and skin commensals 2.
Disease Severity Assessment
Once diagnosed, stage the disease using the Hurley staging system 1, 2:
- Hurley Stage I: Recurrent nodules/abscesses with minimal scarring, no sinus tracts
- Hurley Stage II: One or limited number of sinus tracts with scarring within a body region
- Hurley Stage III: Multiple/extensive sinus tracts and scarring across a body region
Common Diagnostic Pitfalls
Delayed diagnosis is extremely common, averaging 7 years from symptom onset 4. Avoid these mistakes:
- Do not dismiss as simple "boils" or recurrent abscesses requiring only incision and drainage
- Do not confuse with folliculitis or furunculosis—HS has characteristic paired comedones and sinus tract formation
- Do not wait for bacterial culture results—secondary infection may occur, but HS is primarily an inflammatory follicular disease, not an infectious process 5
- Do not overlook disease in patients of normal BMI who don't smoke—while obesity and smoking are strongly associated (odds ratios 33 and 36 respectively), non-obese non-smokers can develop HS 1
Additional Clinical Considerations
Screen for important comorbidities at diagnosis 1:
- Depression and anxiety (higher suicide risk)
- Cardiovascular risk factors (diabetes, hypertension, hyperlipidemia)
- Inflammatory bowel disease (associated with Crohn's disease, not ulcerative colitis)
- Metabolic syndrome
Document baseline pain using a visual analog scale (0-10) and quality of life using the Dermatology Life Quality Index (DLQI) 1, 2.