Duke University researchers have found that sensory neurons in the face and head are directly connected to one of the big emotional signalling hubs in the brain.
This explains why pain from your eyes, ears, and teeth can feel that much worse. Sensory neurons in other body parts are indirectly linked to this hub, according to the study.
The researchers found that irritating a mouse's face led to more activity in the parabrachial nucleus, a part of the brain directly connected to the areas responsible for instinct and emotion, compared to irritating its paw.
This knowledge could lead to more effective ways to treat head and facial pain.
"Usually doctors focus on treating the sensation of pain, but this shows we really need to treat the emotional aspects of pain as well," said senior author Fan Wang in a press release.
Some of the most debilitating head pain comes from migraines. According to Statistics Canada, women are twice as likely to experience them than men.
Earlier this year, migraine sufferers on Twitter started to spread the hashtag #notjustaheadache. They aimed to debunk the idea that the pain stems from women not being able to cope with stress.
Study co-author Wolfgang Liedtke said this is the first biological explanation for why headaches feel so terrible.
"This will open the door toward not only a more profound understanding of chronic head and face pain, but also toward translating this insight into treatments that will benefit people," he said.
More from HuffPost Canada: