Why do your ears burn when you eat spicy food?

The chemicals in the chilli that makes your tongue thinking that the food is really hot also fools your bodys other temperature sensors.

Your body thinks that your temperature is getting too high and starts to try and cool you down.

The usual ways that the body tries to cool itself is through sweating and dilating the blood vessels on the surface of the skin so heat can be lost through the skin. This is why you start going red in the face and ears. The skin on your ears is very thin and when the blood vessels expand they can give off a lot of heat quickly that is why your ears feel hotter and also why you sweat if you eat too much spicy food.