A patch test is a method used to determine if a specific substance causes inflammation of the skin. It is often used to test for allergens. Inflammation is the first response of the immune system to infection or irritation and may be referred to as the innate cascade. ... In zootomy and dermatology, skin is an organ of the integumentary system made up of multiple layers of epithelial tissues that guard underlying muscles and organs. ... An allergen is any substance (antigen), most often eaten or inhaled, that is recognized by the immune system and causes an allergic reaction. ...

The suspected irritant is applied to the skin and held in place with an adhesive patch. Another patch with nothing is also applied as a control. After 24 to 48 hours, the patch is removed. If the skin under the suspect patch is red and swollen, the result is positive and the person is probably allergic to that substance. An allergy can refer to several kinds of immune reactions including Type I hypersensitivity in which a persons body is hypersensitised and develops IgE type antibodies to typical proteins. ...