A variety of skin tests may be performed to diagnose skinallergies, bacterial or fungal skin infections, and other problems affecting the skin. Skin tests are also performed to tell the difference between malignant (cancerous) cells and benign (noncancerous) growths.
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 on the back 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, Gillette blue blade, or a cylindrical punch biopsy tool. Stitches may be 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 (surface scrapings, biopsies, contents of pus bumps and blisters), hair, or nails may be cultured to detect bacteria, fungi, or viruses.
SOURCES: Bruce E. Strober, MD, PhD, associate director of Dermatopharmacology, Department of Dermatology, New York University School of Medicine; co-director of the Psoriasis and Psoriatic Arthritis Center; consultant for Amgen, Biogen, Genentech, Fujisawa, and 3-M. Jeffrey M. Weinberg, MD, director of the Clinical Research Center, St. Luke's-Roosevelt Hospital Center, New York City; assistant clinical professor of dermatology, Columbia University College of Physicians and Surgeons; consultant for Amgen and Genentech. National Institute of Arthritis and Musculoskeletal and Skin Diseases web site. American Academy of Dermatology web site. WebMD Medical Reference with Healthwise: "Psoriasis." American Academy of Dermatology, PsoriasisNet web site. National Psoriasis Foundation web site. Abel, E. "Dermatology III: Psoriaisis," ACP Medicine, April, 2005.