How do you diagnose candidal intertrigo in an adult patient with no significant medical history presenting with erythematous rashes in the axilla, neck, inguinal area, umbilical area, and flank area, and can a KOH (potassium hydroxide) skin scraping be used?

Diagnosis of Candidal Intertrigo

Yes, KOH skin scrapings are an appropriate and recommended diagnostic test for candidal intertrigo, particularly when clinical diagnosis needs confirmation or in treatment-resistant cases. 1, 2

Clinical Diagnosis

Candidal intertrigo is primarily diagnosed based on clinical appearance, which is often sufficient to initiate treatment 3, 2:

• Look for erythematous patches in skin folds (axilla, neck, inguinal area, umbilical area, flank) with peripheral scaling 2, 4
• The hallmark feature is satellite lesions (small pustules or papules surrounding the main area of erythema) that strongly suggest candidal infection 2
• The affected areas typically show moisture, maceration, and opposing skin surfaces in friction 3, 4

Laboratory Confirmation with KOH Preparation

When laboratory confirmation is needed, KOH preparation of skin scrapings is the recommended first-line diagnostic test 1, 2:

How to Perform KOH Preparation:

• Scrape the affected skin at the periphery of the lesion or from satellite lesions 2
• Apply potassium hydroxide (KOH) solution to the specimen 1
• Examine microscopically for characteristic pseudohyphal yeast forms that confirm Candida infection 1, 2

When to Use KOH Testing:

• Treatment-resistant cases where initial therapy has failed 3
• Recurrent infections requiring species identification 3
• When clinical diagnosis is uncertain and you need to distinguish from other causes of intertrigo 2
• To avoid unnecessary exposure to inappropriate treatments when self-diagnosis may be unreliable 1

Additional Diagnostic Options

Culture confirmation is rarely required for initial diagnosis but becomes valuable in specific situations 1, 3:

• Recurrent or resistant cases where species identification and antifungal susceptibility testing may guide therapy 1, 3
• When non-albicans Candida species (such as C. glabrata or C. krusei) with reduced azole susceptibility are suspected 1
• Use fungal selective media to avoid bacterial overgrowth 1

Diagnostic Algorithm

For your patient with erythematous rashes in multiple skin folds:

1. First, examine for satellite lesions - if present, this clinically confirms candidal intertrigo and you can start treatment 2

2. If satellite lesions are absent or diagnosis is uncertain, perform KOH preparation of skin scrapings to look for pseudohyphae 1, 2

3. If KOH is positive, initiate topical antifungal therapy 2

4. If treatment fails after 2 weeks, obtain fungal culture with species identification and susceptibility testing 1, 3

Important Caveats

• Do not delay treatment while awaiting laboratory confirmation if clinical features are characteristic - empiric therapy is appropriate 3, 2
• Address predisposing factors (obesity, diabetes, immunosuppression) as these facilitate both occurrence and recurrence 3, 4
• Bacterial superinfection can coexist with candidal intertrigo; if bacterial infection is suspected, consider bacterial culture or Wood lamp examination 2, 4