KOH Staining, Nail

 KOH (Potassium hydroxide) staining is a simple, non-invasive test that helps diagnose fungal infections of the nails. Cells are collected from the affected area and examined for signs of fungal infections under a microscope.

A KOH test is recommended for individuals with the following symptoms of fungal infections:

• A localized rash
• Red patches which are ring-shaped with scaly edges
• Rashes that did not respond to or worsened with corticosteroid medications or those that persist for months

A KOH test does not explicitly identify the type of fungus; it only shows that fungus is present. In most cases, knowing precisely the fungus causing the rash may not be necessary. The doctor can make an informed judgment and prescribe treatment.