Contact Dermatitis

What is Contact Dermatitis?

Contact dermatitis is an inflammatory condition of the skin. Contact dermatitis manifests as a rash or irritation of the skin caused by contact with a foreign substance. Unlike seasonal allergies which are mediated by IgE, contact dermatitis is mediated by T-cells and requires specialized testing (patch testing) that differs from traditonal skin prick testing.

Your initial exposure does not always cause rash, however, it sensitizes your skin so that you will react to the next exposure. Common substances that can cause allergic reactions, include: hair dyes, metals (ex. nickel), which is found in jewelry, latex rubber and fragrances in soaps, shampoos, lotions, perfumes, and cosmetics.

Patch Testing

Your skin condition may be caused by an allergic response to chemicals you come in contact with. The method to obtain proof of a possible contact dermatitis is to apply patch tests. Sticky patches will be applied to your back that contains different common chemicals found in household end work environments. A positive test reaction will look like a red patch and is sometimes itchy.

Patch Test Procedures

Patch Testing requires 3 office visits in one week. Test allergens will be taped to your back on (1st visit). The patches will be removed in 48 hours (2nd visit) and you will need to return the next day for the doctor to do the final reading (3rd visit). It may be necessary to have an additional read at day 7.

Final Visit: If you have positive reactions, we will prepare information handouts on the chemicals you are sensitive to.

Patch Test Instructions

  1. The test will be applied to the upper back area
  2. Please notify us if you are pregnant
  3. To prevent excessive sweating please refrain from exercising, performing hard work, taking a shower or hot bath. You may take a tepid bath. Do not get the patch test area wet.
  4. Do not take any cortisone medicine during the test. Call if you have any questions about your medications. You must be off oral cortisone (prednisone) for at least 2 weeks prior to this test.
  5. Avoid exposure of the back to the sun.
  6. Do not remove the patch.
  7. Do not rub or scratch the application zone. Itching is an indication of a positive response and scratching might alter the test result.

Food Patch Testing

Food allergy affects between 5% and 7.5% of children and between 1% and 2% of adults. Diagnosing food allergy can be challenging and often requires a trained medical specialist to find the cause. Food allergic patients classically have IgE mediated disease which can be diagnosed with skin prick testing, although there is a subset of patients that will be missed if non-IgE mechanisms are not investigated. Recent studies have examined the use of food patch tests for patients with atopic dermatitis (eczema), eosinophilic esophagitis and other atypical food reactions. Food patch testing is a useful test in evaluating patients and can help identify reactions that are not IgE mediated.

Please bring the following items to your first patch food test

Jarred Baby foods:

  • Chicken
  • Turkey
  • Lamb
  • Ham
  • Beef
  • Sweet Potato
  • Green Beans
  • Banana
  • Apple
  • Squash
  • Carrot
  • Peaches

If you have any questions contact our office at 212-686-6321.

Monday (Patches applied) Wednesday (Patches removed 48 hr reading) Thursday-Friday (72 hour reading by doctor results discussed) Day 7 may be required for reactions which are equivocal at 72-96 hours