The holidays are upon us, and it's time to shower our loved ones with gifts, and receive some in return. But sometimes those clothes, shoes, jewelry, and beauty products can leave an unwanted present: itching and redness.
It's called an allergic contact dermatitis, and can result from different allergens coming into contact with the skin. Cortisone creams often alleviate symptoms, but unless the trigger is identified, the rash can reoccur. The location of
the rash often gives some clues. For example, eyelid rashes are commonly caused by nail polish (especially
containing formaldehyde) and acrylic nails (the glue contains ethyl
methacrylate or methyl methacrylate). When the trigger is not obvious, patch testing is a useful tool.
Dermatologists perform patch testing in the office to reveal allergens. Scratch testing (with needles) is typically done by an Allergist and is used to identify foods or inhlaed allergens (think dust, plants). Patch testing, in contrast, is used to identify allergens that come into contact with the skin.
Patches to the most common allergens (in our office we test 65!) are placed on the back and covered. Two days later, they are uncovered and the skin is inspected to see if any area reacted to the allergen. A final reading is done two days after that. Once the trigger is identified, they can then be avoided in the future.
Common allergens tested include:
preservatives like methylchloroisothiazinolone and imidazolidinyl urea in cosmetics
thimerosal in contact solution
nickel in metals/jewelry
latex/rubber in gloves
formaldehyde in cleaning agents
chromates in leather
mercaptobenzothiazole in rubber (shoes)
para-phenylenediamine in hair dyes
Keep skin looking healthy, merry and bright! Happy holidays!
