How to manage persistent left groin odor and new armpit odor, considering previous treatments with topical clindamycin (clindamycin) and BP (benzoyl peroxide) 2.5% wash, and potential contributing factors such as sedentary lifestyle?

Management of Persistent Groin and New Armpit Odor

Your current clindamycin burst for the groin is appropriate, but your sedentary lifestyle—particularly prolonged bed-sitting under covers—is almost certainly a major contributing factor to both your groin and armpit issues, and addressing this is as critical as any topical therapy. 1

Groin Management: Continue Your Current Plan

Your decision to restart topical clindamycin 1% for the left groin is sound given the pattern of complete suppression on-treatment and recurrence off-treatment. 2

Key points for this burst:

• Duration: 7–10 days is reasonable; the IDSA recommends 5–10 days for skin and soft tissue infections, individualized to clinical response. 3 Stop after 3 consecutive odor-free days or at day 10, whichever comes first. 1

• Application technique: Your thin-film, perimeter-only approach (avoiding deep crease/mucosa) minimizes irritation while targeting the hair-bearing bacterial reservoir. 4, 2

• Benzoyl peroxide alternating: Continue BP 2.5% on alternate days to the same perimeter. The combination of clindamycin plus benzoyl peroxide prevents bacterial resistance that develops with clindamycin monotherapy and provides superior efficacy. 4, 5, 6

• Post-burst maintenance: After this round, transition to BP 2.5% once weekly for 4–6 weeks as planned. This suppresses pathogenic bacterial overgrowth without disrupting normal flora recolonization. 1

Regarding your 60–70% residual odor before restarting clindamycin:

• This level of reduction represents substantial clinical improvement, not true recurrence. 1 After antibiotic therapy disrupts the skin microbiome, commensal bacteria gradually recolonize over 2–4 weeks, producing a mild, different-quality odor during this transition. 1

• The fact that Hibiclens provided minimal benefit suggests you were in the normal microbiome rebalancing phase, not active infection. Hibiclens (chlorhexidine) is appropriate for decolonization in recurrent SSTI but should be used intermittently (e.g., 5–14 days), not continuously, to avoid barrier disruption. 3, 1

Armpit Management: Avoid Repeating the Groin Pattern

Do not use clindamycin in your armpit. The intense odor that responded to Hibiclens suggests transient bacterial overgrowth, not the chronic, localized, topical-antibiotic-responsive pattern you have in the groin. 3

Your current approach is correct:

• Zinc-based antiperspirant: Continue this. It provides both odor control and mild antimicrobial activity without the risks of antibiotic resistance or barrier disruption. 1

• Hibiclens use: Your single application was appropriate for acute odor, but avoid repeated use. The IDSA recommends chlorhexidine body washes for 5–14 days only in the context of recurrent SSTI or household transmission, not for routine odor control. 3

• Character change in odor: The shift to a less severe, more "normal" armpit odor after Hibiclens indicates successful suppression of pathogenic bacteria with recolonization by normal flora—exactly what should happen. 1

If armpit odor worsens again:

• First-line: Benzoyl peroxide 2.5% wash 2–3 times weekly to the armpit (leave on 2–3 minutes, rinse well). This provides antimicrobial activity without antibiotic resistance risk. 4, 1

• Reserve clindamycin only if you develop the same chronic, localized, topical-responsive pattern as your groin (which is unlikely). 2

Lifestyle Modification: The Critical Missing Piece

Your sedentary lifestyle with prolonged bed-sitting under covers is creating a warm, moist, occlusive environment that promotes bacterial overgrowth in both the groin and axillae. 1

Why this matters:

• Moisture and occlusion are primary risk factors for bacterial skin infections. Your observation that "more active days coincide with better skin scent and health" is clinically accurate—activity promotes air circulation, reduces moisture accumulation, and improves skin barrier function. 3, 1

• Even without sweating (as you note), prolonged skin-to-skin contact in the groin fold and covered axillae creates the ideal environment for odor-causing bacteria. 1

Specific recommendations:

• Immediate changes: Even on bed-sitting days, get up every 2–3 hours for 10–15 minutes. Open covers periodically to allow air circulation. 1

• Groin-specific: Your current moisture control protocol (rinse-dry-blow dry after sweat/urine, brief midline positioning) is excellent—continue this rigorously. 1

• Gradual activity increase: You don't need intense exercise. Even 15–20 minutes of walking or standing activity 2–3 times daily will significantly improve skin health. 1

• Tight jeans for work: These are not the problem if you're not sweating. The issue is the prolonged sedentary positioning before/after work. 1

Safety Monitoring

C. difficile risk from topical clindamycin is extremely low—this is a localized, topical-responsive pattern, and oral antibiotics are not indicated. 3, 2

Escalate urgently if you develop:

• Fishy/amine odor persisting despite washing for ≥3 days (suggests erythrasma or bacterial vaginosis-like flora) 1
• Beefy redness, sharp borders, fissures, satellite bumps (suggests candidiasis or dermatitis) 1
• Pain, fever, or spreading rash (suggests deeper infection requiring systemic therapy) 3

Common Pitfalls to Avoid

• Overuse of antiseptics: Hibiclens and other harsh cleansers delay barrier recovery when used continuously. Reserve for acute flares only. 3, 1

• Expecting zero odor: A 70–90% reduction is excellent control. Complete elimination may not be achievable given your anatomic/lifestyle factors. 1

• Neglecting the mechanical factor: All the topical therapy in the world won't overcome prolonged occlusion and moisture. Address the lifestyle component. 1