Allergic contact dermatitis is an immune response to an allergen that makes contact with the skin. The classic example is poison ivy. It can be severely itchy and cause blisters, oozing, redness, swelling and scaling.
The allergens that cause these reactions can be found in natural materials like plants and animals, but can also be found in products in your home environment or those used for skin care. Common allergens include fragrances, metals, dyes, latex, rubber, glues, plastics, preservatives and formaldehyde.
Patch Testing: Since there are so many potential causes of allergic contact dermatitis, a method called patch testing is used to identify the allergens that could be causing your skin’s reaction. Patch testing is a safe, reliable way to diagnose the cause of your allergic contact dermatitis.
Your provider will apply patches containing small amounts of around 80 of the most common allergens to the skin of your upper back. These patches are secured with hypoallergenic tape and typically after 48 hours, your patch test provider will remove the allergens and take note of your skin’s reaction (and lack thereof). Sometimes a second reading, a few days after the first, is required to verify results and provide a more accurate analysis as some allergens can take longer to create a skin reaction.
The results of your patch testing can be used to find skin care products that are free of those ingredients, so you can avoid exposure and prevent the allergic contact dermatitis.