Navigate Up

Men's Center - A-Z Index

#
Q
Y
Z

Print This Page

Wood's lamp examination

A Wood's lamp examination is a test that uses ultraviolet (UV) light to look at the skin closely.

Alternative Names

Black light test; Ultraviolet light test

How the test is performed

You will sit in a dark room for this test. The test usually takes place in a dermatologist's office. The health care provider will turn on the Wood's lamp and hold it 4 - 5 inches from the skin to look for color changes. 

How to prepare for the test

You do not need to take any special steps before this test. Ask your doctor if you avoid putting creams or medicines on the area of the skin being studies before the test. 

How the test will feel

You will feel nothing during this test.

Why the test is performed

Your health care provider may do this to look for skin problems including: 

  • Bacterial infections
  • Fungal infections
  • Porphyria
  • Skin coloring changes such as vitiligo

Normal Values

Normally your skin will not shine under the ultraviolet light.

What abnormal results mean

A Wood's lamp exam may help your doctor confirm a fungal infection or bacterial infection. Your doctor may also be able to learn what is causing any light- or dark-colored spots on your skin.

What the risks are

There are no risks. Avoid looking directly into the ultraviolet light.

Special considerations

The following things can change the results of the test:

  • Washing your skin before the test (may cause a false-negative result)
  • A room that is not dark enough
  • Other materials that glow under the light, such as some deodorants, make-ups, soaps, and sometimes lint

Not all types of bacteria and fungi show up under the light.

References

Harrison S, Piliang M, Bergfeld W. Hair disorders. In: Carey WD, ed. Cleveland Clinic: Current Clinical Medicine 2010. 2nd ed. Philadelphia, Pa: Saunders Elsevier; 2010.

Morelli JG. Evaluation of the patient. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 637.



 

Updated: 11/20/2012

Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.


©  UPMC | Affiliated with the University of Pittsburgh Schools of the Health Sciences
Supplemental content provided by A.D.A.M. Health Solutions. All rights reserved.

For help in finding a doctor or health service that suits your needs, call the UPMC Referral Service at 412-647-UPMC (8762) or 1-800-533-UPMC (8762). Select option 1.

UPMC is an equal opportunity employer. UPMC policy prohibits discrimination or harassment on the basis of race, color, religion, ancestry, national origin, age, sex, genetics, sexual orientation, marital status, familial status, disability, veteran status, or any other legally protected group status. Further, UPMC will continue to support and promote equal employment opportunity, human dignity, and racial, ethnic, and cultural diversity. This policy applies to admissions, employment, and access to and treatment in UPMC programs and activities. This commitment is made by UPMC in accordance with federal, state, and/or local laws and regulations.

Medical information made available on UPMC.com is not intended to be used as a substitute for professional medical advice, diagnosis, or treatment. You should not rely entirely on this information for your health care needs. Ask your own doctor or health care provider any specific medical questions that you have. Further, UPMC.com is not a tool to be used in the case of an emergency. If an emergency arises, you should seek appropriate emergency medical services.

For UPMC Mercy Patients: As a Catholic hospital, UPMC Mercy abides by the Ethical and Religious Directives for Catholic Health Care Services, as determined by the United States Conference of Catholic Bishops. As such, UPMC Mercy neither endorses nor provides medical practices and/or procedures that contradict the moral teachings of the Roman Catholic Church.

© UPMC
Pittsburgh, PA, USA UPMC.com