The sympathetic nervous system kicks in on its own and causes our bodies to release adrenalin and noradrenalin. Noradrenalin relaxes the smooth muscle in the walls of the blood vessels. When this happens the diameter of the vessel increases and more blood passes through the vessel. This is called vasodilation. The ears will feel warm and red.
This usually happens when a person feels nervous, anxiety or stressed and this is referred to part of the "fight or flight" mechanism even tho there may be no threat, may be social. Some people have inherited genes causing the nervous system to be overactive.
We do not consciously control the sympathetic nervous system, it will kick in without our decision to be "embarassed" or whatever.
Our nervous system is part of the autonomic nervous system, the part that controls internal organs functioning. We have no conscious control or sensation. The nerves report back to the brain stem and keeps functioning when our conscious mind is not working.
Uncontrollable blushing is also called Idiopathic Craniofacial Erythema. Many times we have no clue why we are blushing on our ears, neck, arms, face, etc.
I have had this problem for years. Apparently my son inherited the problem and his face, neck ears turn red off and on for unknown reasons.
