Do redheads feel more pain?

A hernia repair is about the simplest surgery out there, but that information didn't lessen the waiting room panic of two parents waiting for our six-month old to wake up from surgery. As soon as the receptionist opened the doors to the recovery ward, we knew our son was fine. Well, maybe not fine, but very much alive, because he was screaming at a volume we'd never heard before. The nurses assured me that my son just needed to breastfeed after overnight fasting. After a fruitless attempt, he was still screaming and both of us were crying, so the nurses relented and gave him fentanyl. We took home a groggy but comfortable child an hour later.

When he needed a second repair two years later, we were prepared. We discussed our son's previous pain management problem, and were reassured things would go more smoothly this time. One of the surgical fellows had gone to medical school with my husband, and our friend and neighbor, a pediatric anesthesiologist, spoke with my son's anesthesiology team. But the end result was nearly identical, except this time there was a two and a half year old capable of throwing himself off a bed and further injuring himself. 

My own experience with pain management has mirrored my son's. I've woken up when I was supposed to be sedated. When I was in labor my first epidural didn't take. When I needed a root canal, it took four rounds of anesthesia to avoid white-hot pain.

In all of these cases, the doctors failed to account for my son's and my red hair. 

That's the claim made by dentists, surgeons, anesthesiologists, and my mother (also a redhead). The redhead anesthesia connection is so well known within the redheaded community that it is an unsourced claim in Jacky Colliss Harvey's otherwise densely-sourced book Red: A History of the Redhead:

Redheads feel more pain than do blonds or brunettes. Or rather, we feel the same amount of pain much more acutely, and thus require much more anesthesia to knock us out--20 percent more being the rule of thumb among anesthetists and surgeons I have spoken to. There is as you might imagine much discussion as to why this should be, how much it varies from redhead to redhead, whether some forms of pain (thermal, for example) are better or worse tolerated by redheads, and which and what anesthetic drugs are thus contraindicated.

Harvey's claims appear to stem from research in the early 2000s into redheads' tolerance for pain and/or resistance to anesthesia. In 2004, researchers conducted a pair of studies drawing a link between the MC1R gene (which is responsible for red hair) and increased sensitivity to pain and/or decreased sensitivity to anesthesia. The first study tested sensitivity to general anesthesia, and concluded that redheaded women required more desflurane than dark-haired women. The second study tested sensitivity to local anesthesia, and found that after receiving lidocaine, redheaded women experienced more thermal pain than dark-haired women. In 2009, the same research group found increased dental-care anxiety in redheads, which they hypothesized was related to either pain tolerance or lowered susceptibility to anesthesia. 

The overall conclusion underlying these studies is that redheads' mutated MC1R gene (which supplies the red hair) also leads to increased sensitivity to pain and decreased sensitivity to anesthetics. These studies led to stories with headlines such as "The Pain of Being a Redhead" and "Why Surgeons Dread Redheads," the comments section of which were loaded with thankful responses from redheads who saw their pain being acknowledged. Our pain's not in our heads. It's in our genetics. 

Except that it might not be.

In 2012, researchers testing different types of anesthesia cast doubt on the original conclusions about redheads, the MC1R gene, and anesthesia requirement. One group confirmed that redheads and non-redheads with MC1R mutations both experienced higher levels of dental anxiety, but found no difference in inferior alveolar nerve block efficacy. In that same year, a different group of researchers found no link between mutations in the MC1R gene and pain tolerance

What might account for such different conclusions about the link between red hair and anesthesia response? It might be just the mention of red hair. 

As Harvey's book makes clear, redheads stick out. Throughout history, redheads have been ascribed with attributes (tempestuous, passionate, etc.), and those stereotypes have endured to our modern time. Those attributes have become a sort of self-fulfilling prophecy. Listen to someone call you impulsive or fiery or short-fused often enough and perhaps that's how you'll react. 

If you are an anesthesiologist recalling your most difficult cases, it would be unsurprising if some of your brightest-haired patients were more memorable than others. There is already a long historical precedent for stereotyping redheads as "other," and it is possible that surgeons' and anesthesiologists' initial conjectures about redheads and anesthesia were just one more form of that stereotyping. Redheads stuck out to anesthesiologists and surgeons as patients who needed more anesthesia, which prompted initial studies looking for a reason redheads needed more anesthesia. 

Those studies also drew attention to red hair, which may have created a confounding variable. The authors of the 2005 study of redheads and lidocaine identified a possible limitation of their work: neither the researchers nor the subjects were blind to hair color. As a result, the researchers could not exclude "bias on the part of the investigators or evaluate the extent to which our bias may have influenced participants' responses." If their hair had been a subject of lore and constant public comment since birth, might the participants already be likely to "know" they were supposed to feel pain differently than others? Could that cultural knowledge have impacted their pain responses? It's possible that redheads are not genetically predisposed to feel more pain, but that they feel more pain because they have been assumed to have more pain. 

The most recent research into hair color and pain tolerance may be more definitive than previous work because, unlike the volunteers in previous studies who knew they were being tested for pain and/or anesthesia response, its subjects were already visiting the hospital for another purpose. Because the subjects were patients already scheduled for surgery, it's less likely that any single question--about use of chemical hair dye, for example--would alert enrollees to the aim of the study. 

There are many ways to explain my son's and my anesthesia responses. Perhaps my son just experiences more pain than typical pediatric surgery patients. The effects of anesthesia might wear off more quickly for him. It's possible his pain had nothing to do with him at all, and is more likely a result of the drug protocol at the hospital where he had his surgeries. Perhaps my son just received a low dose of pain medication because that particular surgical team or that particular hospital is cautious with pain management, preferring the pain to other riskier side effects of anesthesia. There are probably a dozen other explanations, any of them at least as plausible than his hair color. 

The same goes for me. It's possible that my dentist was just dismissing my pain. He was, after all, calling me "dear" and telling me I should feel fine, which suggests my pain may have been less about my hair than his practice. I hope it was my hair causing that explanation, because otherwise I'm seeing red (there's that fiery temper for you).