What is the most likely diagnosis and recommended management for a 60-year-old man with a psychiatric history, unable to give a reliable history, who has a persistently erythematous scrotum without swelling, drainage, or fever, intermittent scrotal pain, and recent urinary incontinence?

Likely Diagnosis: Incontinence-Associated Dermatitis (Contact Dermatitis) with Possible Underlying Pelvic Floor Dysfunction

The most likely diagnosis in this 60-year-old man with isolated scrotal erythema, intermittent pain, and recent urinary incontinence is incontinence-associated dermatitis (contact irritant dermatitis from chronic urine exposure), and you should treat this with barrier protection, hygiene optimization, and investigation of the underlying incontinence cause.

Clinical Reasoning

The constellation of findings—isolated scrotal redness without fever, swelling, or drainage, combined with new-onset urinary incontinence—strongly suggests chronic urine exposure causing irritant contact dermatitis. The psychiatric history and inability to provide history raises concern for self-care deficits and possible occluded urine exposure 1.

Key Diagnostic Considerations

The 2025 AUA guideline on chronic pelvic pain provides a comprehensive differential for scrotal pathology 2. However, most acute surgical emergencies can be excluded here:

• Excluded diagnoses (based on absent fever, swelling, drainage):

  • Epididymitis/orchitis (would show swelling, fever, positive urinalysis)
  • Fournier gangrene or scrotal abscess (would show systemic toxicity, crepitus, drainage)
  • Testicular torsion (acute severe pain, swelling, abnormal lie)
  • Cellulitis (would show warmth, induration, systemic signs)

• Remaining considerations:

  • Incontinence-associated dermatitis (most likely given urine exposure)
  • Pelvic floor myalgia (can cause referred scrotal pain and urinary symptoms) 2
  • Chronic scrotal content pain (CSCP) with secondary skin changes
  • Lichen sclerosus (chronic inflammatory dermatosis associated with urine exposure) 1

The recent urinary incontinence is the critical clue. Male genital lichen sclerosus research demonstrates that chronic occluded exposure to urine in susceptible epithelium causes inflammatory dermatosis, with distribution to urine-exposed sites and association with microincontinence 1.

Immediate Management Algorithm

Step 1: Physical Examination (Perform Today)

Perform a thorough scrotal examination 2:

• Assess scrotal skin: Look for pallor, fissuring, lichenification, or just erythema
• Palpate scrotal contents: Confirm normal testicular size, consistency, and lie
• Check for inguinal lymphadenopathy
• Examine perineum and penis for extension of erythema
• Perform digital rectal exam with pelvic floor muscle palpation: Assess for levator ani and obturator internus tenderness suggesting pelvic floor myalgia 2

Step 2: Diagnostic Testing

• Urinalysis and urine culture: Rule out UTI contributing to incontinence and exclude infectious epididymitis 3
• Scrotal ultrasound: Only if examination reveals any masses, asymmetry, or diagnostic uncertainty about testicular pathology 2
• Post-void residual: Assess for urinary retention contributing to overflow incontinence

Step 3: Initial Treatment (Start Immediately)

For the scrotal erythema:

• Barrier protection: Apply zinc oxide or petroleum-based barrier cream after each void and incontinence episode
• Hygiene optimization: Gentle cleansing with water after urine exposure, pat dry thoroughly
• Avoid occlusion: Use breathable cotton underwear, avoid tight-fitting garments
• Topical corticosteroid: If skin shows lichenification or chronic inflammatory changes, prescribe potent topical corticosteroid (e.g., clobetasol 0.05% ointment twice daily for 2-4 weeks) 1

For pain management (per 2025 AUA CSCP guideline) 3:

• First-line: NSAIDs (e.g., ibuprofen 400-600mg TID with food)
• Second-line: If neuropathic quality, consider low-dose TCA (nortriptyline 10-25mg at bedtime) or gabapentinoid (gabapentin 300mg at bedtime, titrate up)
• Avoid opioids: Not indicated for this presentation

For incontinence:

• Timed voiding schedule (every 2-3 hours while awake)
• Absorbent products with frequent changes
• Refer to urology for formal incontinence evaluation

Step 4: Antibiotic Trial Consideration

Only if antibiotic-naïve and urinalysis suggests possible subclinical infection: Consider single 10-day trial of fluoroquinolone or trimethoprim-sulfamethoxazole 3. However, given the clear incontinence-dermatitis picture, this is likely unnecessary unless urinalysis is abnormal.

Common Pitfalls to Avoid

1. Don't assume psychiatric patients have psychiatric causes for all symptoms: While dermatitis artefacta exists 4, the incontinence history points to a straightforward irritant dermatitis

2. Don't over-image: Scrotal ultrasound is unnecessary when examination is unambiguous and shows only skin changes without testicular abnormality 2

3. Don't prescribe prolonged antibiotics empirically: Only 22% of CSCP cases have infectious causes 3, and this presentation doesn't suggest infection

4. Don't miss pelvic floor dysfunction: The combination of scrotal pain and urinary symptoms warrants rectal exam for pelvic floor myalgia 2, which may be contributing to both complaints

5. Don't ignore the psychiatric history: Ensure adequate follow-up and consider whether cognitive impairment is preventing proper self-care and hygiene

Follow-Up Plan

• 2 weeks: Reassess scrotal skin, pain level, and incontinence pattern
• If no improvement: Consider dermatology referral for possible lichen sclerosus biopsy 1 or urology referral for formal CSCP evaluation 3
• If worsening: Urgent re-evaluation for evolving infectious process (though unlikely given current presentation)

The multimodal approach combining barrier protection, hygiene, topical therapy, and addressing the underlying incontinence should resolve the scrotal erythema within 2-4 weeks 3, 1.