How to Patch Test Skin
Understand the basics., Discuss your medications with your doctor., Be ready for what will happen., Ask about photo-patch testing., Don't be afraid if you think it will be painful., Keep the area dry., Wait two days., Wait another two days., Avoid...
Step-by-Step Guide
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Step 1: Understand the basics.
Patch tests are used to test how allergic you are when you come into contact with certain substances.
Patch tests are different from prick or scratch tests.A scratch test checks for reactions to common allergens that may give you symptoms from hives to a runny nose.
The nurse scratches or pricks the skin to get the allergen under the skin.A patch test checks for just the skin's reaction to the allergen.
A reaction to an allergen by the skin is known as contact dermatitis. -
Step 2: Discuss your medications with your doctor.
Certain medications can affect a patch test.
Antihistamines, for instance, are designed to suppress allergic reactions, which can change the outcome of your patch test.
Your doctor may want you to go off of these medications for a bit before your test, up to 10 days ahead of time.Other medications that may cause problems include tricyclic antidepressants, some medications for acid reflux (such as ranitidine), and omalizumab (an asthma medication)., During a patch test, the nurse or doctor will make up a series of small patches.
Each patch will contain a small amount of a different substance that has been known to cause reactions in some people.
For instance, some patch tests use everything from metals such as cobalt and nickel to lanolin and certain plant types.
The patches will be attached to your skin with medical tape.
Most of the time, the patches are applied to your back or arm., If you commonly have rashes on the back of your hands, your neck, or arms, you may react to a substance only when it comes into contact with sunlight.
A special test exists for this purpose; if you need a photo-patch test, your doctor will place two of each substance and expose one of them to light, while not exposing the other., In fact, unlike scratch tests, patch tests don't use needles at all.
Therefore, you won't experience any pain when the patches are being applied., While the patches are on, you should avoid getting the patches wet, which means avoiding extremes of heat and humidity and heavy sweating.
Do not swim, shower, take a bath, exercise or do anything that might cause the patch to get wet., Generally, the patches are left on you for two days.
You return to the doctor after the time period is up.
The nurse or doctor will remove your patches and look at your skin.
One of them will see which substances your skin shows a reaction to.Reactions on your skin may appear as a rash, possibly with small, raised areas that resemble pimples or fluid-filled sacs. , Sometimes, the doctor will have you return again, four days after the original test.
This step is to see if you had a delayed reaction to an allergen., Once you know what causes you trouble, you know what to avoid.
Your doctor can give you advice on avoiding your particular irritant.
On the other hand, if you don't react to anything, your doctor will look to other issues as the cause of any rashes you may have. -
Step 3: Be ready for what will happen.
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Step 4: Ask about photo-patch testing.
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Step 5: Don't be afraid if you think it will be painful.
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Step 6: Keep the area dry.
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Step 7: Wait two days.
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Step 8: Wait another two days.
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Step 9: Avoid the irritants.
Detailed Guide
Patch tests are used to test how allergic you are when you come into contact with certain substances.
Patch tests are different from prick or scratch tests.A scratch test checks for reactions to common allergens that may give you symptoms from hives to a runny nose.
The nurse scratches or pricks the skin to get the allergen under the skin.A patch test checks for just the skin's reaction to the allergen.
A reaction to an allergen by the skin is known as contact dermatitis.
Certain medications can affect a patch test.
Antihistamines, for instance, are designed to suppress allergic reactions, which can change the outcome of your patch test.
Your doctor may want you to go off of these medications for a bit before your test, up to 10 days ahead of time.Other medications that may cause problems include tricyclic antidepressants, some medications for acid reflux (such as ranitidine), and omalizumab (an asthma medication)., During a patch test, the nurse or doctor will make up a series of small patches.
Each patch will contain a small amount of a different substance that has been known to cause reactions in some people.
For instance, some patch tests use everything from metals such as cobalt and nickel to lanolin and certain plant types.
The patches will be attached to your skin with medical tape.
Most of the time, the patches are applied to your back or arm., If you commonly have rashes on the back of your hands, your neck, or arms, you may react to a substance only when it comes into contact with sunlight.
A special test exists for this purpose; if you need a photo-patch test, your doctor will place two of each substance and expose one of them to light, while not exposing the other., In fact, unlike scratch tests, patch tests don't use needles at all.
Therefore, you won't experience any pain when the patches are being applied., While the patches are on, you should avoid getting the patches wet, which means avoiding extremes of heat and humidity and heavy sweating.
Do not swim, shower, take a bath, exercise or do anything that might cause the patch to get wet., Generally, the patches are left on you for two days.
You return to the doctor after the time period is up.
The nurse or doctor will remove your patches and look at your skin.
One of them will see which substances your skin shows a reaction to.Reactions on your skin may appear as a rash, possibly with small, raised areas that resemble pimples or fluid-filled sacs. , Sometimes, the doctor will have you return again, four days after the original test.
This step is to see if you had a delayed reaction to an allergen., Once you know what causes you trouble, you know what to avoid.
Your doctor can give you advice on avoiding your particular irritant.
On the other hand, if you don't react to anything, your doctor will look to other issues as the cause of any rashes you may have.
About the Author
John Young
Experienced content creator specializing in practical skills guides and tutorials.
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