Master the board step 3

Dermatology
Infections
Fungal Infections
These are the following:
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Tinea pedis
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Tinea cruris
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Tinea corporis
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Tinea versicolor
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Tinea capitis
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Onychomycosis
Diagnostic Testing
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Best initial test: Potassium hydroxide (KOH) test of the skin. The leading
edge of the lesion on the skin or nails is scraped with a scalpel to remove
some of the epithelial cells or some of the nail and hair. KOH has the ability
to dissolve the epithelial cells and collagen of the nail but not the fungus.
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Most accurate test: Culture the fungus. Molds that grow on the skin (dermatophytes)
take up to 6 weeks to grow, even on specialized fungal media.
A specific species usually does not need to be isolated in most cases, unless
the infection is of the hair or nails.
Treatment
For onychomycosis (nail infection) or hair infection (tinea capitis), the medications
with the greatest efficacy are oral terbinafine or itraconazole. These
medications are used for 6 weeks for fingernails and 12 weeks for toenails.
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Terbinafine is potentially hepatotoxic, and it is important to check liver
function tests periodically.
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Griseofulvin must be used for 6–12 months and has much less antifungal
efficacy than terbinafine.
All of the other fungal infections of the skin that don’t involve the hair or
nails may be treated with any of the following topical medications:
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Ketoconazole
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Clotrimazole
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Econazole
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Terbinafine
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Miconazole
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Sertaconazole
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Sulconazole
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Tolnaftate
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Naftifine
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