*H&P: Can have a clear border (allergic, type IV hypersensitivity, e.g '''nickel''', poison ivy) or not (irritant, e.g. nickel, makeup, detergents). | *H&P: Can have a clear border (allergic, type IV hypersensitivity, e.g '''nickel''', poison ivy) or not (irritant, e.g. nickel, makeup, detergents). |