Acrylic Allergy, Cosmetic Allergy, Fragrance Allergy, Nickel & Metal Allergy, Industrial Chemical Allergy

Eczema, contact dermatitis, dermatitis, nickel allergy, allergy to poison ivy, and chemical allergy (such as cosmetics, fragrances, acrylics etc.) are T cell mediated. This is called DELAYED HYPERSENSITIVITY. The reaction starts many hours after the contact and has much longer duration. It takes up to a few weeks to wear off, and often becomes chronic on repeated or persistent exposure. This type of allergy can occur to metals, glues, and cements used in surgical implants. Evaluation prior to hip and knee joint replacements (details here) or implantation of other devices may be indicated depending on a patient’s history. If you are interested in being evaluated for contact dermatitis, please call us at (650) 368-8807.

Contact dermatitis means inflammation of the skin caused by contact with a chemical substance. This can happen if the substance is an irritant such as acid or bleach. Given long enough exposure at high enough concentration, everyone will get inflammation. This is called IRRITANT CONTACT DERMATITIS.

In contrast, ALLERGIC CONTACT DERMATITIS occurs only if a person develops a T cell mediated allergy to the chemical. Since it is a delayed onset chronic reaction, it is often not obvious as to what is causing the rash.

PATCH TESTS are performed to identify the chemicals your T cells have become sensitized to. This identifies and allows one to avoid contact with products that may contain those chemicals.

Food allergies, when they are responsible for atopic dermatitis, eczema, eosinophilic esophagitis, irritable bowel syndrome (IBS), and eosinophilic gastrointestinal disease (EGID), can affect patients through both above mentioned mechanisms. Food allergy patients may need both prick and patch tests for the suspected foods.

How Is Contact Dermatitis Patch Testing Performed?

Patch tests are performed using the standard antigen list prepared and recommended per current guidelines.The list contains 80 of the most common antigens North Americans are likely to be exposed to.

Visit 1: During the initial visit, the patch test panels will be placed on the back. These panels consist of suspect chemicals in a neutral base, filled in small plastic chambers. The panels are taped to the skin. These panels must remain in contact with the skin for 48 hours, unless there is pain or severe itching. This requires that they do not get wet or shift location on the back. So bathing and working out is not allowed until after your second visit!

Visit 2: 48 – 72 hours after patch placement. The panels are removed, first readings are recorded. After this visit you can have a shower but do not soap the back and be very gentle with the towel so you do not rub off the ink markings. They are required for reading on the third visit. Visit 3: 5 – 7 days after patch placement, the tests are read again and the results are reviewed.

There are standard panels as well as customized panels for orthopedic and dental procedures. We can also customize patch test for specific implants and chemicals.