What is the best course of action for a 50-year-old male with uncontrolled Diabetes Mellitus (DM) presenting with painless, non-itchy, red patches on the glans penis and testicles for one month, with a history of high-risk sexual behavior one year prior and currently being sexually inactive?

Diagnostic and Management Approach for Red Patches on Glans and Scrotum in Uncontrolled Diabetic Patient

This patient most likely has candidal balanitis and scrotal dermatitis secondary to uncontrolled diabetes, and should be treated with topical antifungal therapy (clotrimazole or miconazole cream twice daily for 2-3 weeks) combined with aggressive glycemic control optimization.

Immediate Diagnostic Steps

The clinical presentation strongly suggests fungal infection given the key features:

• Red patches on glans penis and scrotum in the setting of uncontrolled diabetes is pathognomonic for candidal infection 1
• Non-vesicular, painless, non-pruritic lesions for one month duration rules out herpes simplex virus (which would be vesicular and painful) 2
• Uncontrolled diabetes is the single most important risk factor, creating a glucose-rich environment that promotes Candida overgrowth 2, 1

Essential Workup

Perform the following immediately:

• KOH preparation from scrotal and glans skin scrapings to identify fungal elements (pseudohyphae and budding yeast) 3
• Fungal culture if KOH is negative but clinical suspicion remains high 3
• HbA1c and fasting glucose to quantify degree of glycemic control 2, 1
• Complete STI screening including HIV, syphilis (RPR/VDRL), and HSV-2 serology given high-risk sexual behavior one year ago 2
• Physical examination specifically assessing for phimosis (which increases infection risk 25-60%), inguinal lymphadenopathy, and extent of erythema 2

Critical Differential Diagnoses to Exclude

High Priority (Rule Out First)

1. Penile squamous cell carcinoma: Although less likely given bilateral scrotal involvement, any persistent penile lesion in a 50-year-old warrants biopsy if not responding to antifungal therapy within 2-3 weeks 2

2. Secondary syphilis: Can present as painless red patches; the one-year timeframe from high-risk exposure fits the natural history. Order RPR/VDRL immediately 2

3. Fixed drug eruption: Review all medications, particularly antihypertensives and antidepressants which are common in diabetics 2

Lower Priority (Consider if Initial Treatment Fails)

1. Red scrotum syndrome: Typically follows prolonged topical corticosteroid use, presents with severe burning/itching (absent in this patient), and has sharp borders 4, 5, 3, 6

2. Psoriasis or lichen sclerosus: Would typically have scaling or white plaques respectively 2

Treatment Algorithm

Step 1: Immediate Management (Week 1-3)

Initiate empiric antifungal therapy while awaiting culture results:

• Topical clotrimazole 1% or miconazole 2% cream applied twice daily to affected areas for minimum 2-3 weeks 3
• Continue for one week after clinical resolution to prevent recurrence 3
• Avoid topical corticosteroids which can worsen fungal infections and cause red scrotum syndrome 4, 5, 3

Simultaneously optimize diabetes control:

• Target HbA1c <7% as poor glycemic control directly correlates with infection severity (odds ratio 2.3) 1
• Poor glycemic control is the primary driver of recurrent genital candidiasis 2, 1

Step 2: Reassessment at 2-3 Weeks

If complete resolution: Continue antifungal for one additional week, maintain glycemic control, and provide prevention counseling 3

If partial improvement: Extend antifungal therapy to 4-6 weeks and consider adding oral fluconazole 150mg weekly for 2-4 doses 3

If no improvement or worsening:

• Perform punch biopsy of the most indurated or suspicious area to rule out malignancy (penile SCC has 5-year survival of only 50% overall, but >85% if caught early with negative lymph nodes) 2
• Reassess STI results and treat accordingly if positive 2
• Consider red scrotum syndrome if patient reports severe burning (treat with doxycycline 100mg twice daily for 2-3 months plus gabapentin or pregabalin for neuropathic symptoms) 4, 5, 6

Critical Pitfalls to Avoid

1. Do not assume this is "just diabetes-related ED": The erectile dysfunction guidelines focus on sexual function, not dermatologic manifestations. This patient has a skin infection, not erectile dysfunction 2, 7

2. Do not delay biopsy if lesions persist beyond 3 weeks of appropriate antifungal therapy: Penile cancer can masquerade as balanitis, and diabetes is a risk factor (odds ratio 2.3) 2, 1

3. Do not prescribe topical corticosteroids: This will worsen fungal infection and can induce red scrotum syndrome, creating a chronic rebound vasodilation problem 4, 5, 3

4. Do not ignore the STI risk: One year post-exposure is within the window for secondary syphilis, which presents identically to this clinical picture 2

5. Do not treat empirically for syphilis without testing: If RPR/VDRL is positive, treat with benzathine penicillin G 2.4 million units IM, but confirm diagnosis first 2

Long-Term Prevention Strategy

Once acute infection resolves:

• Maintain HbA1c <7% as this is the single most important factor preventing recurrence 2, 1
• Daily gentle cleansing with water and mild soap, ensuring complete drying 3
• Avoid occlusive clothing and moisture-trapping undergarments 3
• Consider circumcision if recurrent infections occur in the setting of phimosis (which carries 25-60% increased infection risk) 2

When to Refer

• Urology referral if biopsy shows dysplasia or malignancy, or if phimosis prevents adequate examination 2
• Dermatology referral if red scrotum syndrome is confirmed or if lesions persist despite appropriate antifungal and antibiotic therapy 5, 3, 6
• Endocrinology referral if HbA1c remains >9% despite primary care optimization 1