Why do the outer rims of my ears feel warm to touch and have red itchy small bumps ?

Red itchy rash ears: Often ears are first to be affected if there is an allergic reaction to hair dye. Ears are swollen, red & itchy with small vesicles. Ingredient in hair color that does it is paraphenalinediamine, component of hair dye that gives it black color, present in all hair dyes except bleached blond. If this happened after dying your hair, please see derm as reactions can be severe & worse w/each exposure.