Skin Conditions: Diagnosing Skin Problems

A variety of skin tests may be performed to diagnose skin allergies, bacterial or fungal skin infections, and other diseases affecting the skin. Skin tests are also performed to tell the difference between malignant (cancerous) cells and benign (non-cancerous) growths.

The most common skin tests include:

• Patch testing: Patch tests are used to help diagnose skin allergies. Identified allergens (substances that a person may be allergic to) are applied to the skin with adhesive patches and left for a period of time. The skin is then examined for any reaction.
• Skin biopsy: Skin biopsies are performed to diagnose skin cancer or benign skin disorders. During a skin biopsy, skin is removed (after a local anesthetic is applied) and is taken to a laboratory for analysis. Skin may be removed with a scalpel or a cylindrical punch. Sutures are often used to close the wound.
• Culture: A culture is a test that is done to identify the microorganism (bacteria, fungus, or virus) that is causing an infection. Skin, hair, or nails may be cultured to detect bacteria, fungi, or viruses.

Reviewed by doctors at The Cleveland Clinic Department of Dermatology.