Increased Sensitivity to Thermal Pain and Reduced Subcutaneous Lidocaine Efficacy in Redheads

Abstract

Background: Anesthetic requirement in redheads is exaggerated, suggesting that redheads may be especially sensitive to pain. We therefore tested the hypotheses that women with natural red hair are more sensitive to pain, and that redheads are resistant to topical and subcutaneous lidocaine.

Red hair and anesthetic requirement

“…19 Redheads are also more sensitive to thermal pain and resistant to the analgesic effects of subcutaneous lidocaine. 20 Consistent with these experimental results, a subsequent cross-sectional study found that participants with MC1R gene variants reported significantly more dental care-related anxiety and fear of dental pain than participants with no MC1R gene variants. Subjects with the mutation were also more than twice as likely to avoid dental care as participants without MC1R gene variants, even after controlling for general trait anxiety and sex.…”

“…19 Les roux sont également plus sensibles à la douleur thermique et résistants aux effets analgésiques de la lidocaïne sous-cutanée. 20 Une étude transversale ultérieure a abouti à des conclusions compatibles avec ces résultats expérimentaux: les participants porteurs de variants du gène MC1R ont déclaré éprouver significativement plus d'anxiété envers les soins dentaires et de craintes de douleurs dentaires que les participants sans variant du gène MC1R. Les patients porteurs de la mutation étaient également deux fois plus susceptibles d'éviter les soins dentaires que les patients sans variants du gène MC1R, même après un ajustement pour le trait de personnalité anxieuse et le sexe.…”

A Common Variant in the MC1R Gene (p.V92M) is associated with Alzheimer’s Disease Risk

“…This receptor may have an important role in the anti-inflammatory brain response [16] and in female specific mediation mechanisms of analgesia [40]. MC1R is also expressed in melanocytes, a cell type with a common embryonic origin with brain cells [41], which determine hair and skin color [42], and certain variants increase the risk for skin cancer (melanoma and non-melanoma skin cancer) [18,19].…”

Thermal quantitative sensory testing to assess the sensory effects of three local anesthetic solutions in a randomized trial of interscalene blockade for shoulder surgery

“…27 Reaction-time exclusive methods, such as the method of levels, are even more time-consuming (extending the duration of testing up to 60-80 min per patient), excluding their application in clinical research projects. 27 As an alternative to thermal QST protocols, the Neurometer Ò , a current perception threshold (CPT Ò ) device, applies electric current perception thresholds to assess nerve function after LA administration; 28,29 however, this option exhibits less reliability and considerably more variability than thermal QST. Furthermore, patients detect thermal stimuli more easily than CPT stimuli.…”