Medical Terminology: Skin Tests

1. What are Skin Tests?
Skin is the largest and most visible organ in the body and is susceptible to wrinkles, blemishes, growths (including both nonmelanoma and melanoma), and infection. Health care providers perform an assortment of tests and procedures to diagnose and treat skin conditions.
Lesions, warts, and blemishes that make skin unsightly and unhealthy can be removed by performing one of a number of procedures. For example, undesired tissue can be frozen with cryosurgery and removed, or layers of skin can be peeled away using chemicals or micrographic surgery. Layers can also be removed using curettage, electrosurgery, or the dermabrasion procedure in which a rotating burr scrapes scars and aging skin to encourage new skin growth.
Melanoma and nonmelanoma skin cancer affects many patients. The health care provider can cure or minimize the discomfort of this condition by performing a skin excision where the tumor is surgically removed.
Infected skin can be treated once the microorganism that causes the infection is identified. The health care provider is able to identify the microorganism by performing a wound culture in which a sample of the infected tissue is placed in an environment that is favorable for the growth of microorganism (culture) and then identified. Once the lab determines which medication will fight the microorganism, the medication is administered to the microorganism.
Skin is also a perfect site for testing for allergic reactions. There are several tests that health care providers administer to the skin to identify allergens that cause the patient to develop an allergic reaction. The skin is also the site of the Mantoux skin test to determine if the patient has ever been exposed to Mycobacterium tuberculosis.

2. Chemical Peel
A chemical peel is performed to cosmetically improve the patient’s skin.

Understanding the Chemical Peel
A chemical peel is a procedure that exfoliates injured or dead skin, enabling new skin to replace it. There are three types of chemical peels:
. Superficial: This procedure removes the surface layer of the skin for a smoother, brighter appearance, and uses glycolic acid or dry ice for the peel.
. Medium: This procedure is commonly used to smooth fine wrinkles, remove blemishes, and treat pigment problems. It uses trichloroacetic acid (TCA) for the peel.
. Deep: This procedure is commonly used to correct coarse wrinkles and blotches on the face only and uses phenol for the peel. New skin might be lighter in tone because the skin loses some ability the produce pigment.
A chemical peel might change the patient’s skin tone and result in scarring and cold sores. It might cause flaking and dryness.

3. Allergy Skin Test
An allergy skin test is performed to identify the source of a patient’s allergic reaction.

Understanding the Allergy Skin Test
An allergen is a substance that causes an immune reaction. Allergy skin testing is performed to identify allergens. There are three types of skin testing for allergens:
. Skin Patch Test: This test is used to identify allergens that cause contact dermatitis and requires the placement of a pad that contains an allergen solution on the skin for 72. hours. An allergic reaction occurs if the patient is allergic to the allergen.
. Skin Prick Test: This test requires that a drop of an allergen solution be placed on the patient’s skin. The skin is scratched, allowing the allergen solution to penetrate the skin. A wheal occurs if the patient is allergic to the allergen.
. Intradermal Test: This test requires that a small amount of an allergen solution be injected into the dermal layer of the skin. A wheal occurs if the patient is allergic to the allergen.

4. Dermabrasion
Dermabrasion is performed to remove scars or growths from the upper layer of the skin and to remove wrinkles.

Understanding Dermabrasion
Dermabrasion is a procedure that removes the upper layers of damaged skin caused by scars and aging to encourage new skin growth. The procedure is performed by using a rotating burr to remove damaged tissue.

5. Mantoux Skin Test
The Mantoux skin test is performed to identify if the patient is or was ever exposed to Mycobacterium tuberculosis.

Understanding the Mantoux Skin Test
The Mantoux skin test determines if the patient has ever been exposed to M. tuberculosis. The health care provider injects the purified protein derivative (PPD), which is the M. tuberculosis, into the patient’s forearm. If the patient develops a wheal within 48. hours, indicating a positive immune response, then the patient either is or had been infected with M. tuberculosis. However, a positive Mantoux skin test doesn’t always indicate that the patient has or had tuberculosis. Some patients may have received a tuberculosis vaccination that causes a positive result. A chest X-ray is taken to diagnose a current infection of M. tuberculosis should there be a positive immune response to the test.

6. Wound Culture
A wound culture is ordered to assess the existence and type of microorganism that is causing a skin infection. It is also used to assess which medication to use to treat the skin infection.

Understanding the Wound Culture Test
A wound culture is ordered when the patient is suspected of having a skin infection. A tissue sample of the infected area is taken and placed in an environment conducive to the growth of microorganisms for 3. days. The tissue sample is then examined to identify the presence and type of microorganism. Once the microorganism is identified, a sensitivity test is usually performed to determine the medication that kills the microorganism.

Basic Questions
Skin Tests

1. Why might a chemical peel be ordered?
A chemical peel is performed to cosmetically improve the patient’s skin.

2. How does a chemical peel work?
A chemical peel is a procedure that exfoliates injured or dead skin, enabling new skin to replace it.

3. What is a superficial chemical peel?
This procedure removes the surface layer of the skin for a smoother, brighter appearance, and uses glycolic acid or dry ice for the peel.

4. What is a medium chemical peel?
This procedure is commonly used to smooth fine wrinkles, remove blemishes, and treat pigment problems.

5. What is a deep chemical peel?
This procedure is commonly used to correct coarse wrinkles and blotches on the face only.

6. Why might a health care provider use glycolic acid?
Glycolic acid is used for a superficial chemical peel.

7. When would a health care provider use phenol?
Phenol is used for a deep chemical peel.

8. What is a risk of performing a chemical peel?
A chemical peel might change the patient’s skin tone and result in scarring and cold sores. It might cause flaking and dryness.

9. Why might a patient’s new skin following a deep chemical peel have a lighter tone than the patient’s normal skin?
New skin might be lighter in tone because the skin loses some ability to produce pigment.

10. Why might the health care provider use trichloroacetic acid (TCA)?
TCA is used for a medium chemical peel.

11. Why might a health care provider order an allergy skin test?
An allergy skin test is performed to identify the source of a patient’s allergic reaction.

12. What is an allergen?
An allergen is a substance that causes an immune reaction.

13. What is a skin patch test?
This test is used to identify allergens that cause contact dermatitis and requires the placement of a pad that contains an allergen solution on the skin for 72. hours. An allergic reaction occurs if the patient is allergic to the allergen.

14. What is a skin prick test?
This test requires that a drop of an allergen solution be placed on the patient’s skin. The skin is scratched, allowing the allergen solution to penetrate the skin.

15. How do you know if the skin prick test is positive?
A wheal occurs if the patient is allergic to the allergen.

16. What is an intradermal test?
This test requires that a small amount of an allergen solution be injected into the dermal layer of the skin.

17. Why is dermabrasion performed?
Dermabrasion is performed to remove scars and growths from the upper layer of the skin and to remove wrinkles.

18. How is dermabrasion performed?
The procedure is performed by using a rotating burr to remove damaged tissue.

19. Why is the Mantoux skin test ordered?
The Mantoux skin test is used to determine if the patient has or was exposed to Mycobacterium tuberculosis.

20. What is the purified protein derivative (PPD)?
The PPD is the M. tuberculosis antigen.

21. Where is the PPD injected?
The PPD is injected into the patient’s forearm.

22. How do you determine if the Mantoux skin test is positive?
If the patient develops a wheal within 48. hours, indicating a positive immune response, then the patient either is or had been infected with M. tuberculosis.

23. Does a positive Mantoux skin test mean that the patient has or had tuberculosis?
No. Some patients may have received a tuberculosis vaccination that causes a positive result.

24. What might the health care provider do if the patient has a positive Mantoux skin test?
A chest X-ray is taken to diagnose a current infection of M. tuberculosis should there be a positive immune response to the test.

25. Why is a wound culture ordered?
A wound culture is ordered to assess the existence and type of a microorganism that is causing a skin infection. It is also used to assess which medication to use to treat the skin infection.