This is used to evaluate a patient who presents with a dermatitis that may be allergic in nature. Patch tests used at Sand Lake Dermatology Center were developed by the North American Contact Dermatitis Society and include the most common allergens (triggers) that we see including fragrance, metals, and preservatives. The patches are usually applied on Friday and interpreted the following Monday and Wednesday. If an allergen is identified, then avoidance of the trigger can be undertaken. Patch testing does not check for food allergies, molds or pollen.