Dermatophytosis and KOH microscopy

What it is

Dermatophytosis is the fungal infection also known as ringworm or tinea. It is limited to the stratum corneum, hair and nail, and it takes several distinct clinical entities depending on the anatomic site. Athlete's foot, which is tinea pedis, is usually caused by fungi in the genus Trichophyton.

How it presents

The type of ringworm depends upon the site of involvement, and the name follows the site:

• Tinea capitis: scalp.
• Tinea barbae: beard and moustache.
• Tinea faciei: face excluding beard and moustache.
• Tinea corporis: trunk and extremities.
• Tinea cruris: groin.
• Tinea pedis: soles or toes.
• Tinea manum: palm.
• Tinea unguim: nail.

On the feet the picture is typically scaling, flaking, and itching between the toes, and it can present as a whitish lesion between the toes.