Ringworm of the Skin

Exams and Tests

Doctors often can easily recognize ringworm by its ring-shaped rashClick here to see an illustration.. Your doctor will probably also look at a skin sample (KOH preparation) under a microscope to confirm that fungus is present.

Tests for ringworm of the skin include:

  • A KOH (potassium hydroxide) preparation. This test can help your doctor find out whether a fungus is causing your rash. The doctor will take a sample of your skin by lightly scraping the infected area. The sample is placed on a slide with potassium hydroxide (KOH) solution and gently heated. If fungus cells are present, the doctor can then see them with a microscope.
  • A fungal culture (skin culture). This test can identify the type of fungus that is causing your infection. Usually a culture is only done if the diagnosis is difficult or the skin condition is not responding to treatment. This test may take up to 4 weeks, because it takes time for the fungus to grow.

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Author: Maria G. Essig, MS, ELSLast Updated: April 19, 2007
Medical Review: Kathleen Romito, MD - Family Medicine
Randall D. Burr, MD - Dermatology

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Topic Contents
 Topic Overview
 Cause
 Symptoms
 What Happens
 What Increases Your Risk
 When To Call a Doctor
Arrow PointerExams and Tests
 Treatment Overview
 Prevention
 Home Treatment
 Medications
 Surgery
 Other Treatment
 Other Places To Get Help
 Related Information
 References
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