You are being patch tested to determine if your skin condition is caused by an allergic reaction. You are being tested to allergens in personal products such as fragrances and preservatives, sunscreens and metals.
Before the initial visit: Do not take antihistamines 3 days prior to testing (i.e. Benadryl, Claritin, Zytrec, Atarax, etc.) or during the testing procedure. Do not take oral steroids (i.e. Prednisone) one week prior to testing or during the testing period unless it was discussed with the physician.
1st visit: Adhesive patches are placed on your back.
Between the 1st and 2nd visit: The area must be kept dry. Avoid heavy physical activity. If you notice any loosening of the patches, have someone apply additional tape to the edges of the chamber units.
2nd visit: This is done two days later. The patches are removed and positive reactions are noted. Bring in your products or a printout of your product's ingredients! If you have a positive reaction, the doctor can look through the ingredients to see if the offending allergen is in your products. Note that detergent does not list the ingredients on the bottle, so you will have to look online for this and print it out.
Between the 2nd and 3rd visit: There will be ink markings on your back. They should be remarked with a marker twice a day.
3rd visit: This takes place two to four days later. Once again, bring in your products or a printout of their ingredients. The final reading will be done. Handouts will be given on all positive allergens. In addition, a personalized "safe list" of personal care products that can be used will be emailed to you. (Check your junk mail!)
Allergic Contact Dermatitis: Frequently Asked Questions
1. What does it look like?
It is a rash that is typically red, itchy, and scaly that resembles eczema. It can also cause swelling when it affects eyelids.
2. What causes it?
Preservatives and fragrances found in personal care products such as shampoos, conditioners, body washes, soaps, facial cleansers and detergent are among the most common causes. Other culprits include sunscreens, metals, cortisones, hair dyes and nail polish.
3. When will it go away?
This will vary. After the offending agent is stopped, it usually takes two to eight weeks for the rash to subside. But often it can take up to three to six months for the rash to completely dissipate.
4. How can I just suddenly develop an allergy? I have not been using any new products. I have been using the same product for years.
Allergic contact dermatitis develops after "chronic sensation." This means that after repeated long term exposure to the allergen, the body suddenly develops an allergy. It often occurs after may years of being exposed to the allergen.
5. I only flare up with the rash once a month, but I use my shampoo that you say I am allergic to every day. How could this be?
Contact dermatitis typically has flare ups and then quiet periods of remissions, even if the offending agent is being used.
6. I used my shampoo five days ago but the rash only started last night - how could this be?
Contact dermatitis is a "delayed hypersensitivity reaction." Often it can take up to one week for the rash to come out after the offending agent is used.