What is the best course of treatment for a 20s male with persistent mild musty/cheesy odor in the left groin fold, suspected to be caused by bacterial imbalance or overgrowth, who has already tried topical antifungals (clotrimazole), antibacterial soap (Hibiclens, chlorhexidine), and topical antibiotic (clindamycin) with temporary resolution of symptoms?

Recommended Treatment Approach for Persistent Groin Odor After Clindamycin Response

Continue clindamycin for the full 7-day course and then transition to maintenance therapy with benzoyl peroxide wash or dilute bleach baths to prevent bacterial recolonization, while managing the new folliculitis with topical corticosteroids if needed. 1

Understanding Your Clinical Response

The dramatic improvement with clindamycin confirms this is a bacterial overgrowth problem, most likely involving Corynebacterium species or other skin commensals that produce malodorous metabolites. 1 The fact that Hibiclens (chlorhexidine) provided temporary relief also supports bacterial etiology rather than fungal infection. 1

The Red Bumps: Expected Complication

The appearance of red bumps 2 days after completing clindamycin is likely antibiotic-associated folliculitis or irritant contact dermatitis, both common complications of topical antibiotic use in intertriginous areas. 1 This does NOT mean you should stop treatment prematurely.

• Folliculitis can paradoxically occur after antibiotics disrupt the normal skin microbiome, allowing resistant organisms or yeast to proliferate in hair follicles. 1
• The groin area's occlusive environment (despite powder use) increases risk of follicular irritation. 1

Immediate Management Plan

Complete the Antibiotic Course

• Finish the full 7-day clindamycin regimen even though you're experiencing mild folliculitis. 1 Stopping antibiotics prematurely risks bacterial resistance and rapid recolonization. 1
• The mild sour scent you're noticing is likely residual bacterial metabolites clearing from the skin, not treatment failure. 1

Address the Folliculitis Concurrently

• Apply hydrocortisone 1% cream (over-the-counter) to the red bumps twice daily for 3-5 days maximum. 1 This reduces inflammation without significantly impairing bacterial clearance.
• Avoid occlusive powders directly over the bumps during this period—they can worsen follicular plugging. 1

Long-Term Maintenance Strategy

The critical issue is preventing bacterial recolonization after antibiotic discontinuation. Your history shows that both Hibiclens and clindamycin work temporarily but the problem recurs—this indicates you need ongoing antimicrobial maintenance, not repeated antibiotic courses. 1

Primary Maintenance Option: Benzoyl Peroxide Wash

• Use benzoyl peroxide 4-10% wash (e.g., PanOxyl, Neutrogena) in the affected groin fold 2-3 times weekly. 1
• Apply to damp skin, leave on for 1-2 minutes, then rinse thoroughly. 1
• Benzoyl peroxide provides sustained antibacterial activity against Corynebacterium and other odor-producing bacteria without promoting resistance. 1
• Caution: Benzoyl peroxide bleaches fabrics—use white towels and underwear on treatment days. 1

Alternative Maintenance: Dilute Bleach Baths

• Add ½ cup regular household bleach (6% sodium hypochlorite) to a full bathtub of water twice weekly. 1
• Soak for 10 minutes, focusing on submerging the groin area. 1
• This approach is particularly effective for patients with recurrent bacterial skin issues and doesn't cause folliculitis. 1

Role of Gladskin (Micreobalance®)

• Continue the Gladskin as adjunctive therapy—it selectively targets Staphylococcus aureus while preserving beneficial skin flora. 1
• However, it likely won't address Corynebacterium overgrowth, which is the probable primary culprit given your "cheesy" odor description. 2
• Use it daily as a complementary measure, not as monotherapy. 1

What NOT to Do

Avoid Repeated Antibiotic Courses

• Do not restart clindamycin or try other topical antibiotics (erythromycin, mupirocin) for maintenance. 1 This promotes antibiotic resistance and disrupts the skin microbiome, creating a cycle of temporary improvement followed by worse rebound overgrowth. 1
• The guideline evidence is clear: systemic antibiotics for non-infected skin colonization leads to rapid recolonization and resistance. 1

Don't Assume Fungal Recurrence

• Your dermatologist cleared the original tinea cruris, and clotrimazole provided no benefit on rechallenge. 3
• The dramatic response to antibacterial agents (Hibiclens, clindamycin) definitively rules out active fungal infection. 3
• Continuing antifungals would be futile and potentially harmful by further disrupting your skin microbiome. 1

Addressing the Urine Dribble Factor

The occasional urine exposure you mentioned is a significant contributing factor that standard treatments don't address. 2

• Urine creates an alkaline environment that promotes bacterial growth and malodor production. 2
• After urination, use unscented baby wipes or a damp washcloth to clean the groin fold, then pat completely dry. 1
• Consider using absorbent cotton pads (like panty liners) in the groin fold during the day, changed 2-3 times daily, to prevent urine accumulation. 1
• This mechanical approach is more sustainable than relying on antimicrobials alone. 1

Expected Timeline

• Days 5-7 of clindamycin: Folliculitis should resolve with hydrocortisone; odor should remain minimal. 1
• Week 2 (post-antibiotic): Begin benzoyl peroxide or bleach bath maintenance. Expect odor to stay controlled if maintenance is consistent. 1
• Weeks 3-4: If odor recurs despite maintenance, this suggests inadequate hygiene technique or a need for more frequent antimicrobial maintenance (increase to 3-4 times weekly). 1

When to Seek Further Evaluation

Return to your dermatologist if:

• Folliculitis worsens or becomes pustular despite hydrocortisone—may need culture to rule out MRSA. 1
• Odor returns to baseline severity despite consistent maintenance therapy—may need bacterial culture to identify specific organisms. 1
• New symptoms develop: pain, swelling, fever, spreading redness—these suggest deeper infection requiring systemic antibiotics. 1

Why This Approach Works

Your case demonstrates bacterial dysbiosis, not infection. 1 The skin's normal flora has shifted toward odor-producing species, likely Corynebacterium (which produces the characteristic "cheesy" smell through lipid metabolism). 2, 4

• Clindamycin temporarily suppresses these bacteria. 5, 4
• Without ongoing antimicrobial pressure, they rapidly recolonize from adjacent skin or environmental sources. 1
• Maintenance therapy with non-antibiotic antimicrobials (benzoyl peroxide, bleach) prevents recolonization without promoting resistance. 1
• Addressing mechanical factors (urine exposure, moisture) removes the conditions that favor bacterial overgrowth. 1

This is a chronic management issue, not a curable infection—success requires consistent maintenance, not intermittent treatment courses. 1