II. Indication
- Suspected fungal infection (KOH Preparation negative)
- Sensitivity to Antifungal Medications
III. Approach: General
- Submit large amounts of debris
- Break up large pieces
- Collect in sterile urine cup or similar container
IV. Technique: Specimen collection
- Scaly Rash
- Collect scale as done in KOH Preparation
- Implant resulting scales on medium
- Non-Scaling Rash
- Wet cotton swab rubbed vigorously over lesion border
- Collect resulting debris into medium
- Nails
- See Onychomycosis
- Clip nails back to yellowish, crumbly portion
- Clip a sliver of crumbly portion and place on medium
- Gently scrape debris from under free edge of nail
- Scalp
- See Tinea Capitis
- Gently scrub area with sterile ToothBrush
- Tap ToothBrush bristles on medium
- Scrape a few scales off scalp for culture
- Gently pluck short stumps of hair and place on medium
V. Preparations: Culture Medium
- Medium: Sabouraud's Peptone-Glucose Agar (most common)
- Additives: Dermatophyte test medium (DTM)
- Phenol indicator turns red when alkaline
- Poor sensitivity and Specificity
VI. Technique: Culture Identification
- Dermatophyte growth and identification takes 4-6 weeks
- Minimum culture time to call negative: 21 days
- Keep culture bottle at room Temperature
- Do not tightly cap bottles (loose enough to rattle)
- Dermatophytes are aerobes