What is the likely cause and recommended management for a persistent itchy axillary rash in a 50-year-old man?

Persistent Itchy Axillary Rash in a 50-Year-Old Male

This is most likely intertrigo (intertriginous dermatitis) with possible secondary candidal or bacterial infection, and you should start with topical antifungal therapy (clotrimazole or ketoconazole cream twice daily) combined with a low-potency topical corticosteroid (hydrocortisone 1% cream) for 2–4 weeks, while implementing aggressive moisture control and friction reduction measures. 1, 2, 3

Immediate Clinical Assessment

Look for these specific features to guide your diagnosis:

• Erythema with peripheral scaling in the axillary folds suggests classic intertrigo 1
• Satellite lesions (small pustules or papules surrounding the main rash) strongly indicate secondary candidal infection 1
• Crusting, weeping, or yellow discharge suggests bacterial superinfection with Staphylococcus aureus 4, 5, 1
• Grouped vesicles or punched-out erosions would indicate eczema herpeticum (medical emergency requiring immediate acyclovir) 5

First-Line Treatment Strategy

For uncomplicated intertrigo with suspected candidal involvement:

• Apply topical azole antifungal (clotrimazole 1% or ketoconazole 2% cream) twice daily to affected areas 1, 2
• Add hydrocortisone 1% cream twice daily for 2–4 weeks maximum to control inflammation and itching 4, 5
• The combination addresses both the fungal component and the inflammatory response simultaneously 1

If bacterial superinfection is present (crusting, weeping, pustules):

• Prescribe oral flucloxacillin as first-line systemic antibiotic for S. aureus 5, 1
• Continue topical corticosteroids during bacterial infection when appropriate systemic antibiotics are given concurrently—do not withhold steroids 5
• For penicillin allergy, use oral erythromycin 5, 1

Essential Moisture and Friction Control Measures

These non-pharmacologic interventions are the cornerstone of management and prevent recurrence:

• Keep the axillary area completely dry throughout the day—pat dry thoroughly after bathing, never rub 2, 3
• Use absorptive powders (cornstarch) or barrier creams to minimize moisture accumulation 2
• Wear light, loose-fitting cotton clothing; avoid wool and synthetic fibers that trap moisture 2
• Shower immediately after physical exercise and dry intertriginous areas meticulously 2
• Avoid all alcohol-containing preparations (deodorants, aftershaves) as they worsen dryness and trigger flares 6, 7

Skin Care Protocol

• Use mild, pH-neutral (pH 5) non-soap cleansers or dispersible creams as soap substitutes to preserve natural skin lipids 4, 6
• Bathe with lukewarm water only—hot water stimulates sweating and worsens the condition 7
• Do not apply heavy emollients, moisturizers, or occlusive products to active intertrigo, as these trap heat and promote secondary infection 7, 2

Managing Pruritus

• Sedating antihistamines (diphenhydramine, hydroxyzine) may help nighttime itching through sedation, not direct antipruritic effect 5, 7
• Non-sedating antihistamines have no value in intertrigo and should not be prescribed 5, 7
• Use short-term only as adjunct—they do not replace topical anti-inflammatory therapy 5

Treatment Duration and Follow-Up

• Continue topical antifungal for 2–4 weeks even after clinical improvement to prevent recurrence 1
• Limit topical corticosteroid to 2–4 weeks maximum to avoid skin atrophy, then implement "steroid holidays" 4, 5
• Re-evaluate at 48–72 hours if bacterial infection was suspected to assess antibiotic response 5

Common Pitfalls to Avoid

• Do not delay topical corticosteroids when infection is present—they remain primary treatment when appropriate systemic antibiotics are given 5
• Avoid applying greasy ointments or occlusive dressings to active intertrigo, as these worsen sweat duct obstruction and promote infection 7, 2
• Do not use potent or very potent corticosteroids in thin-skinned intertriginous areas where atrophy risk is higher 4, 5
• Avoid topical acne medications (retinoids) as they cause excessive drying and irritation 7

When to Escalate or Refer

• Failure to respond after 2–4 weeks of appropriate topical therapy 5
• Recurrent infections despite optimal treatment—consider underlying predisposing factors (diabetes, obesity, immunosuppression) 8, 3
• Suspected eczema herpeticum (grouped vesicles, punched-out erosions, fever)—this is a medical emergency requiring immediate oral or IV acyclovir 5
• Diagnostic uncertainty or atypical presentation 5, 6

Address Predisposing Factors for Long-Term Success

• Weight loss in obese patients significantly reduces recurrence 8, 3
• Screen for and manage diabetes mellitus—poor glycemic control facilitates candidal overgrowth 8
• Evaluate for immunosuppressive conditions in recurrent or treatment-resistant cases 8