The connection between redheads and pain is a subject of much interest among researchers, who have discovered that the gene responsible for red hair appears to play a role in pain perception as well. Redheads tend to be more sensitive to pain and find that some analgesics are less effective. In addition, they may require more anesthesia to maintain a state of sedation, something particularly important for doctors and medical providers preparing for medical procedures. Paradoxically, certain painkillers are actually more aggressive in redheads.
Genetically, the explanation behind the link with redheads and pain involves a mutated gene. In people with other hair colors, the gene produces a hormone receptor that makes melanin when triggered by the body. Redheads have a hormone receptor of a slightly different shape, which results in fair skin and reddish hair. Meanwhile, the hormone intended to lock on to that receptor is still present in the body, and it needs somewhere to go.
This receptor is in the same family as those involved in the transmission of pain signals. As a result, the hormone formulated to attach to it can also lock on to pain receptors, triggering the sensation of pain. For redheads, painful stimuli can feel more intense because they are more sensitive. In medical settings, the redheads and pain connection can be important, because care providers may need to be careful during procedures that only cause mild discomfort in others.
Awareness of the link between redheads and pain is also important for analgesia. Many local anesthetics wear off more quickly in redheads, a particular problem in dental surgery, where they are used to control pain during drilling and other procedures. The dentist may need to use more, without using so much that the patient is exposed to the risk of a bad reaction. Anesthesiologists also need to consider redheads and pain when they make plans for surgery, as it may be necessary to increase the dose to keep the patient fully anesthetized.
Some redheads also appear to be more prone to bruising, although their blood appears to clot normally and they are not at increased risk of blood disorders. This may be a result of their fairer skin, which makes it easier to see light bruises that might be hidden under people with deeper skin tones. People can also experience increased sensitivity at the site of a bruise if they have red hair, which can make bruises seem larger and more common than they are in other people.