Contact Hypersensitivity Usually maximal at 48 hours Predominantly an epidermal reaction Langerhans cells are the antigen presenting cells a dendritic antigen presenting cell carry antigen to lymph nodes draining skin Associated with hapten-induced eczema nickel salts in jewellry picryl chloride acrylates p-Phenylene diamine in hair dyes ■chromates ·chemicals in rubber ▣poison ivy(urushiol) Contact Hypersensitivity ◼ Usually maximal at 48 hours ◼ Predominantly an epidermal reaction ◼ Langerhans cells are the antigen presenting cells ◼ a dendritic antigen presenting cell ◼ carry antigen to lymph nodes draining skin ◼ Associated with hapten-induced eczema ◼ nickel salts in jewellry ◼ picryl chloride ◼ acrylates ◼ p-Phenylene diamine in hair dyes ◼ chromates ◼ chemicals in rubber ◼ poison ivy (urushiol)