The blushing brain: neural substrates of cheek temperature increase in response to self-observation.

Darwin proposed that blushing-the reddening of the face owing to heightened self-awareness-is 'the most human of all expressions'. Yet, relatively little is known about the underlying mechanisms of blushing. Theories diverge on whether it is a rapid, spontaneous emotional response that does not involve reflection upon the self or whether it results from higher-order socio-cognitive processes. Investigating the neural substrates of blushing can shed light on the mental processes underlying blushing and the mechanisms involved in self-awareness. To reveal neural activity associated with blushing, 16-20 year-old participants (n = 40) watched pre-recorded videos of themselves (versus other people as a control condition) singing karaoke in a magnetic resonance imaging scanner. We measured participants' cheek temperature increase-an indicator of blushing-and their brain activity. The results showed that blushing is higher when watching oneself versus others sing. Those who blushed more while watching themselves sing had, on average, higher activation in the cerebellum (lobule V) and the left paracentral lobe and exhibited more time-locked processing of the videos in early visual cortices. These findings show that blushing is associated with the activation of brain areas involved in emotional arousal, suggesting that it may occur independently of higher-order socio-cognitive processes. Our results provide new avenues for future research on self-awareness in infants and non-human animals.

The unique contribution of blushing to the development of social anxiety disorder symptoms: results from a longitudinal study.

BACKGROUND: Self-conscious emotional reactivity and its physiological marker - blushing has been proposed to be an etiological mechanism of social anxiety disorder (SAD), but so far, untested in longitudinal designs. This study tested, for the first time, whether self-conscious emotional reactivity (indexed as physiological blushing) contributes to the development of SAD symptoms over and above social behavioral inhibition (BI), which has been identified as the strongest predictor of SAD development in early childhood. METHODS: One hundred fifteen children (45% boys) and their mothers and fathers participated at ages 2.5, 4.5, and 7.5 years. Social BI was observed at all time points in a stranger approach task, and physiological blushing (blood volume, blood pulse amplitude, and temperature increases) was measured during a public performance (singing) and watching back the performance at ages 4.5 and 7.5. Child early social anxiety was reported by both parents at 4.5 years, and SAD symptoms were diagnosed by clinicians and reported by both parents at 7.5 years. RESULTS: Higher social BI at 2.5 and 4.5 years predicted greater social anxiety at 4.5 years, which, in turn, predicted SAD symptoms at 7.5 years. Blushing (temperature increase) at 4.5 years predicted SAD symptoms at 7.5 years over and above the influence of social BI and early social anxiety. CONCLUSIONS: That blushing uniquely contributes to the development of SAD symptoms over and above social BI suggests two pathways to childhood SAD: one that entails early high social BI and an early onset of social anxiety symptoms, and the other that consists of heightened self-conscious emotional reactivity (i.e. blushing) in early childhood.

Treatment Options for Fear of Blushing.

PURPOSE OF REVIEW: To review mechanisms of blushing and fear of blushing from physiological, neuropharmacological and psychological viewpoints, and to evaluate current forms of treatment for blushing-related fear. RECENT FINDINGS: Blushing appears to be driven primarily by sympathetic adrenomedullary and neural vasodilator discharge, possibly in association with secondary neurovascular inflammation. Psychological risk factors for fear of blushing include social anxiety, coupled with heightened self-focused attention and inflated beliefs about the likelihood and social costs of blushing. In addition, schemas of emotional inhibition, social isolation and alienation may underlie blushing-related fears. Established psychological treatments for fear of blushing include task concentration training, exposure, cognitive therapy, social skills training, psychoeducation and applied relaxation. More novel approaches include mindfulness and mindful self-compassion, video feedback and imagery rescripting. There are no established pharmacological treatments specifically for fear of blushing. However, selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors are effective treatments for social anxiety disorder and may thus help some patients manage their fear of blushing. A reactive sympathetic nervous system may interact with psychological predispositions to intensify fear of blushing. These physiological and psychological risk factors could be promising targets for treatment.

Facial blushing influences perceived embarrassment and related social functional evaluations.

Facial blushing involves a reddening of the face elicited in situations involving unwanted social attention. Such situations include being caught committing a social transgression, which is typically considered embarrassing. While recent research has demonstrated that facial redness can influence social evaluations, including emotional states such as perceived anger, the influence of blushing on social perceptions related to embarrassment or social transgression has yet to be investigated. Across three experiments, we manipulated the redness of neutral faces (Exp. 1) and faces displaying different emotional expressions (Exps. 2 and 3), and had participants evaluate perceived embarrassment, apology sincerity, and likeliness to forgive a transgression for each set of stimuli. Results indicated that redder (relative to baseline) faces influenced perceived embarrassment, apology sincerity, and likeliness to forgive a transgression. We discuss the implications in the context of a social functional account of facial colour in emotion expression and perception.

Etiologies and management of cutaneous flushing: Nonmalignant causes.

The flushing phenomenon may represent a physiologic or a pathologic reaction. Although flushing is usually benign, it is prudent that the physician remains aware of potentially life-threatening conditions associated with cutaneous flushing. A thorough investigation should be performed if the flushing is atypical or not clearly associated with a benign underlying process. The diagnosis often relies on a pertinent history, review of systems, physical examination, and various laboratory and imaging modalities, all of which are discussed in the 2 articles in this continuing medical education series. This article reviews flushing associated with fever, hyperthermia, emotions, menopause, medications, alcohol, food, hypersensitivity reactions, rosacea, hyperthyroidism, dumping syndrome, superior vena cava syndrome, and neurologic etiologies.

Autonomic arousal in children of parents with and without social anxiety disorder: a high-risk study.

OBJECTIVE: Autonomic hyperarousal in social situations is considered a genetic vulnerability factor for social anxiety disorder (SAD), but so far it is unstudied in children at risk for developing SAD. We examined autonomic activity during socially stressful tasks in children of mothers and fathers with and without lifetime SAD to reveal possible biological mechanisms of intergenerational transmission of SAD. METHODS: One hundred ten children aged 4.5 years were asked to sing a song in front of an audience and watch back their performance in the presence of that audience. Heart rate (HR), heart rate variability (HRV), electrodermal activity (EDA), and blushing (cheek blood flow and temperature) were measured in anticipation of, during, and after the tasks. Both parents' lifetime SAD status was assessed, and both parents reported about their own and their child's social anxiety symptoms. RESULTS: Children of parents with lifetime SAD blushed more during the socially challenging tasks than children of parents without SAD. Moreover, children of parents with more social anxiety symptoms showed increased EDA throughout the tasks. Finally, more blushing, increased EDA, and reduced HRV were associated with greater child social anxiety. CONCLUSIONS: This study adds to the current knowledge on the intergenerational transmission of SAD by providing evidence that children at risk for SAD are characterized by excessive blushing in socially challenging situations. The findings also demonstrate that heightened autonomic activity is a characteristic of social anxiety already during early childhood. Hence, autonomic hyperarousal, and blushing in particular, is likely to play an etiological role in the development of SAD.

Judgmental Biases of Individuals with a Fear of Blushing: The Role of Relatively Strict Social Norms.

Blushing-fearful individuals often expect that others will judge them negatively. In two studies, we tested if this could be explained by having relatively strict beliefs about what is appropriate social behaviour. Study 1 used a student sample (n = 74), whereas study 2 compared a clinical treatment-seeking sample of blushing-fearful individuals (n = 33) with a non-anxious control group (n = 31). In both studies, participants were asked to read descriptions of common behaviours that could be considered as breaching the prevailing social norms but not necessarily so. Participants indicated (i) to what extent they considered these behaviours as violating the prevailing norm and (ii) their expectation of observers' judgments. Study 1 showed that strict norms were indeed related to fear of blushing and that the tendency of fearful participants to expect negative judgments could at least partly explain this relationship. Study 2 showed that high-fearful and low-fearful individuals do indeed differ in the strictness of their norms and that especially the norms that individuals apply to themselves might be relevant. These findings may provide fresh clues for improving available treatment options. KEY PRACTITIONER MESSAGES: Blushing-fearful individuals attribute relatively strict social norms to other people about which behaviours are appropriate and which are not and have stricter personal norms as well. Blushing-fearful individuals' tendency to expect overly negative judgments in ambivalent social situations can partly be explained by their relatively strict social norms. Having relatively strict social norms may (also) explain why blushing-fearful individuals report to blush often and intensely. It may be worthwhile to address strict social norms in therapy for fear of blushing.

Cognitive Therapy and Task Concentration Training Applied as Intensified Group Therapies for Social Anxiety Disorder with Fear of Blushing-A Randomized Controlled Trial.

The current study examines the efficacy of intensified group therapy for social anxiety disorder with fear of blushing. Task concentration training (TCT) and cognitive therapy (CT) were applied during one weekend and compared with a waiting list condition in a randomized controlled trial including 82 patients. On a second weekend, another intervention was added (resulting in TCT-CT and CT-TCT sequences) to examine order effects. Task concentration training and CT were both superior to the waiting list and equally effective after the first therapy weekend. Also, no differences were found between the sequences TCT-CT and CT-TCT at post-assessment. At 6- and 12-month follow-up, effects remained stable or further improved. At the 6-month follow-up, remission rates in completers, established by diagnostic status, were between 69% and 73%. Intensified group therapy is highly effective in treating social anxiety disorder with fear of blushing. Group formats for patients sharing a common primary concern may contribute to the dissemination of cognitive-behavioural therapy. Copyright © 2015 John Wiley & Sons, Ltd. Key Practitioner Message: This study focuses on blushing from fearful individuals within the SAD spectrum to improve evidence for treatment efficacy in those whose social fears are centred around observable bodily sensations. This study integrates task concentration training into the SAD model of Clark and Wells to combine two evidence-based treatments for SAD under one treatment model. This study uses an innovative format of brief, intensified group therapy, conducted on two full-day weekend group sessions delivered over two weekends, with strong observed effect sizes.

Sympathicotomy for isolated facial blushing: long-term follow-up of a randomized trial.

OBJECTIVES: Thoracoscopic sympathicotomy may be an effective treatment for disabling facial blushing in selected patients. Short- and mid-term results are good but very long-term results are scarce in the medical literature and there is no knowledge which extent of sympathicotomy is better long-term for isolated facial blushing. METHODS: We previously randomized 100 patients between a rib-oriented R2 or R2-R3 sympathicotomy for isolated facial blushing, and reported local effects, side effects and quality of life after 12 months. In the present study, we sent identical questionnaires to all patients after a median of 16 years (interquartile range 15-17 years). RESULTS: The response rate was 66%. Overall, 82% reported excellent or satisfactory results on facial blushing, with significant better local effect after R2 sympathicotomy compared with R2-R3 sympathicotomy. Patients who underwent R2 sympathicotomy were also significantly more satisfied with the operation. We found no significant difference between R2 and R2-R3 sympathicotomy in quality of life or rates of compensatory sweating (77%) and recurrence of blushing (41%) which was milder than preoperatively in most patients. CONCLUSIONS: R2 sympathicotomy should be the preferred approach for isolated facial blushing because of better local effect and higher satisfaction rates. Although this was a very long-term follow-up of the only randomized trial of its kind the response rate was limited leaving a risk of undetected bias.

Changes in electrodermal activity following sympathicotomy in hyperhidrosis patients.

Objectives: The aim of this study was to assess the potential of electrodermal activity (EDA) as a diagnostic tool for preoperative evaluation in hyperhidrosis patients. EDA levels and patterns in different skin areas were investigated before and after endoscopic thoracic sympathicotomy (ETS) and was compared to healthy subjects. Methods: Thirty-seven patients underwent two days of measurements before and after the operation. Twenty-five (67.5%) of the patients also had a third measurement after six months. Non-invasive EDA measurements, involving skin conductance, were sampled from five different skin areas while patients were at rest in supine and sitting positions or when subjected to stimuli such as deep inspirations, mental challenge, and exposure to a sudden loud sound. Results: Prior to the operation, hyperhidrosis patients showed higher spontaneous palm EDA variations at rest and stronger responses to stimuli compared to healthy subjects. Patients with facial blushing/hyperhidrosis or combined facial/palmar hyperhidrosis showed minimal spontaneous activity or responses, particularly during mental challenge and sound stimulus. Notably, palm EDA response was abolished shortly following sympathicotomy, although a minor response was observed after six months. Minimal EDA responses were also observed in the back and abdomen postoperatively. Conclusion: Hyperhidrosis patients showed stronger EDA response to stimuli compared to healthy subjects. Sympathicotomy resulted in the complete elimination of palm EDA responses, gradually returning to a limited extent after six months. These findings suggest that EDA recordings could be utilized in preoperative assessment of hyperhidrosis patients.

Neural cell-types and circuits linking thermoregulation and social behavior.

Understanding how social and affective behavioral states are controlled by neural circuits is a fundamental challenge in neurobiology. Despite increasing understanding of central circuits governing prosocial and agonistic interactions, how bodily autonomic processes regulate these behaviors is less resolved. Thermoregulation is vital for maintaining homeostasis, but also associated with cognitive, physical, affective, and behavioral states. Here, we posit that adjusting body temperature may be integral to the appropriate expression of social behavior and argue that understanding neural links between behavior and thermoregulation is timely. First, changes in behavioral states-including social interaction-often accompany changes in body temperature. Second, recent work has uncovered neural populations controlling both thermoregulatory and social behavioral pathways. We identify additional neural populations that, in separate studies, control social behavior and thermoregulation, and highlight their relevance to human and animal studies. Third, dysregulation of body temperature is linked to human neuropsychiatric disorders. Although body temperature is a "hidden state" in many neurobiological studies, it likely plays an underappreciated role in regulating social and affective states.

Development of a novel nomogram to predict the risk of severe compensatory sweating following endoscopic thoracic sympathectomy.

BACKGROUNDS: Endoscopic thoracic sympathectomy (ETS) is a permanent and effective treatment for primary hyperhidrosis and facial blushing; however, severe compensatory sweating (SCS) remains a devastating complication. We aimed to (i) construct a nomogram to predict the risk of SCS, and (ii) investigate factors associated with the level of satisfaction. METHODS: From Jan 2014 to Mar 2020, 347 patients underwent ETS by a single surgeon. These patients were asked to complete an online questionnaire regarding primary symptom resolution, level of satisfaction, and development of compensatory sweating. Multivariable analysis was conducted via logistic regression and ordinal regression to predict SCS and satisfaction level respectively. Nomogram was developed based on significant predictors. RESULTS: In total, 298 (85.9%) patients responded to the questionnaire with a mean follow up of 4.9 ± 1.8 years. Significant factors associated with SCS in the nomogram included older age (OR 1.05, 95% CI 1.02-1.09, P = 0.001), primary indication other than palmar hyperhidrosis (OR 2.30, 95% CI 1.03-5.12, P = 0.04), and current smoking (OR 5.91, 95% CI 2.46-14.20, P < 0.001). The area under receiver operating characteristic curve was 0.713. Multivariable analysis revealed that longer follow up (ß = -0.201 ± 0.078, P = 0.01), gustatory hyperhidrosis (ß = -0.781 ± 0.267, P = 0.003), primary indication other than palmar hyperhidrosis (ß = -1.524 ± 0.292, P < 0.001), and SCS (ß = -3.061 ± 0.404, P < 0.001) were independently associated with a lower degree of patient satisfaction. CONCLUSION: The novel nomogram can provide a personalized numerical risk estimate to assist both the clinician and patient weigh the pros and cons as part of the decision-making process, mitigating the chance of patient dissatisfaction.

Reactivity of observers' facial skin blood flow depending on others' facial expressions and blushing.

Facial skin blood flow (SkBF) has attracted attention as an autonomic indicator because it influences facial colour, which informs others of emotional states, and facial temperature related to social anxiety. Previous studies have examined the facial SkBF in people experiencing emotions; however, facial SkBF changes in the observers of emotions are poorly understood. Our study clarified facial SkBF changes related to observing others' emotions by comparing the changes with other physiological indices. Thirty healthy participants (24 females; mean age: 22.17) observed six types of facial expressions (neutral, angry, and embarrassed expressions with and without facial blushing) and rated the emotional intensity of the other person. We measured their facial SkBF, finger SkBF, and cardiac RR interval as they made their observations. Facial SkBF generally decreased in relation to observing emotional faces (angry and embarrassed faces) and significantly decreased for angry expressions with blushing. None of the participants noticed blushing of facial stimuli. For the RR interval and finger SkBF, there was no variation depending on the observed facial expressions, although there was a general increase related to observation. These results indicated that facial SkBF is sensitive and reactive to emotional faces-especially angry faces with blushing- compared with other autonomic indices. The facial SkBF changes were not related to either RR interval changes or the intensity rating, suggesting that facial SkBF changes may be caused by vasoconstriction and have potential functions for our emotions. The decrease in facial SkBF may have a role in calming observers by preventing them from adopting the same emotional state as a person with intense anger. These findings clarify daily facial SkBF fluctuations and their relationship with our emotional processing in interpersonal situations.

Staged single-port thoracoscopic R2 sympathicotomy as a reproducible, safe and effective treatment option for debilitating severe facial blushing.

OBJECTIVES: Our goal was to investigate the safety, feasibility, success rate, complication rate and side effects of staged single-port thoracoscopic R2 sympathicotomy in the treatment of severe facial blushing. Facial blushing is considered a benign condition; however, severe facial blushing can have a major impact on quality of life. When nonsurgical options such as medication and psychological treatments offer no or insufficient relief, surgical treatment with thoracoscopic sympathicotomy should be considered. METHODS: All patients who underwent a staged thoracoscopic sympathicotomy at level R2 for severe facial blushing between January 2016 and September 2021 were included. Clinical and surgical data were prospectively collected and analysed. RESULTS: A total of 16 patients with low operative risk (American Society of Anesthesiologists class 1) were treated. No major perioperative complications were encountered. One patient experienced postoperative unilateral Horner's syndrome that resolved completely after 1 week. Two patients experienced compensatory hyperhidrosis. The success rate was 100%. One patient experienced a slight recurrence of blushing symptoms after 3 years that did not interfere with their quality of life. All patients were satisfied with the results and had no regrets of having undergone the procedure. CONCLUSIONS: Staged single-port thoracoscopic R2 sympathicotomy is a reproducible, safe and highly effective surgical treatment option with low compensatory hyperhidrosis rates and the potential to significantly improve quality of life in carefully selected patients suffering from severe facial blushing. We would like to increase awareness among healthcare professionals for debilitating facial blushing and suggest timely referral for surgical treatment.

Do your troubles today seem further away than yesterday? On sleep's role in mitigating the blushing response to a reactivated embarrassing episode.

The "sleep to forget and sleep to remember hypothesis" proposes that sleep weakens the emotional tone of an experience while preserving or even enhancing its content. Prior experimental research however shows contradictory findings on how emotional reactivity changes after a period of sleep, likely explained by methodological variations. By addressing these inconsistencies, we investigated the mitigating effect of overnight sleep on emotional reactivity triggered by memory reactivation. Using a karaoke paradigm, we recorded participants' singing of two songs, followed by exposing them to one of the recordings (rec1) to induce an embarrassing episode. After a 12-hr period of either day-time wakefulness (N = 20) or including nighttime sleep (N = 20), we assessed emotional reactivity to the previously exposed recording (rec1) and the newly exposed recording (rec2). Emotional reactivity was assessed with a physiological measure of facial blushing as the main outcome and subjective ratings of embarrassment and valence. Sleep and wake were monitored with diaries and actigraphy. The embarrassing episode was successfully induced as indicated by objective and subjective measures. After controlling for an order effect in stimulus presentation, we found a reduction in blushing response to the reactivated recording (rec1) from pre- to post-sleep compared to wakefulness. However, emotional reactivity to the reactivated recording (rec1) and the new recording (rec2) did not differ after sleep and wakefulness. This study shows that facial blushing was reduced following overnight sleep, while subjective ratings were unaffected. Whether the beneficial effect of sleep is due to changes in memory representation or rather emotion regulation remains elusive.

Minimally Invasive Sympathicotomy for Palmar Hyperhidrosis and Facial Blushing: Current Status and the Hyperhidrosis Expert Center Approach.

Hyperhidrosis, the medical term for excessive sweating beyond physiological need, is a condition with serious emotional and social consequences for affected patients. Symptoms usually appear in focal areas such as the feet, hands, axillae and face. Non-surgical treatment options such as topical antiperspirants or systemic medications are usually offered as a first step of treatment, although these therapies are often ineffective, especially in severe and intolerable cases of hyperhidrosis. In the treatment algorithm for patients suffering from hyperhidrosis, surgical thoracoscopic sympathicotomy offers a permanent solution, which is particularly effective in the treatment of palmar hyperhidrosis and facial blushing. In this review, we describe the current status of thoracoscopic sympathicotomy for palmar hyperhidrosis and facial blushing. In addition, we share the specific treatment approach, technique and results of our Hyperhidrosis Expert Center. Last, we share recommendations to ensure an effective, reproducible and safe application of single-port thoracoscopic sympathicotomy for palmar hyperhidrosis and facial blushing, based on our extensive experience.

What's in a blush? Physiological blushing reveals narcissistic children's social-evaluative concerns.

Physiological responses can reveal emotional states that individuals are unwilling to admit to others. Here, we studied what blushing reveals about the emotional states of narcissistic children. Narcissistic children (i.e., those high on the personality trait of narcissism) have a pervasive sense of grandiosity. We theorized that narcissistic children are so invested in their sense of grandiosity that even modest praise can make them feel depreciated. Because narcissistic children may not admit this feeling to others, we measured their physiological blushing: an involuntary reddening of the face that occurs when individuals anticipate being depreciated. Unlike other emotional expressions, blushing cannot be faked. Children (N = 105, ages 7-12) completed the Childhood Narcissism Scale and were then invited to sing a song on stage. They were randomly assigned to receive inflated praise (e.g., "You sang incredibly well!"), modest praise ("You sang well!"), or no praise for their performance. Blushing was recorded using photoplethysmography and temperature sensing. Afterward, children were asked how much they thought they had blushed. As predicted, narcissistic children-unlike nonnarcissistic children-blushed when they received modest praise, not when they received inflated praise. Specifically, they showed increased blood volume pulse (i.e., fast changes in blood volume with each heartbeat). Strikingly, when asked, narcissistic children denied blushing, perhaps to hide their vulnerabilities. Thus, blushing revealed social-evaluative concerns that narcissistic children wished to keep private.

When gushing leads to blushing: Inflated praise leads socially anxious children to blush.

Blushing is an involuntary reddening of the face that typically occurs when people are concerned about making negative impressions on others. Although people typically blush for their mishaps or misdeeds, Darwin observed that some people, and especially children, also blush when they are lavished with praise. We theorize that socially anxious children blush when praised in inflated ways because they believe they do not match the inflated image others hold of them. Such praise-induced blushing might be particularly common in late childhood, when children's worries about their social image escalate. In this randomized experiment, 105 children (ages 8-12, 85% Caucasian) sang in front of an audience. Afterwards, children received inflated praise ("You sang incredibly well!"), noninflated praise ("You sang well!"), or no praise. Children's physiological blushing was assessed through photoplethysmography and a temperature sensor. As predicted, inflated praise-but not non-inflated praise-increased blushing in socially anxious children. This emerged for blood pulse amplitude changes (AC reactivity) and self-reported blushing, not for blood volume (DC reactivity) and temperature changes. Socially anxious children may blush to "apologize" in advance for not being as incredible as others think they are. Thus, blushing may be elicited in situations that seem benign but actually evoke the fear of being evaluated negatively.

Sympathetic ganglionectomy for facial blushing using application of laser speckle flow graph.

OBJECTIVE: Endoscopic thoracic sympathectomy at the second rib level is considered effective as a therapeutic treatment for facial blushing. However, 10% to 15% of patients do not benefit from this intervention. No additional procedure has been developed for this disorder. Recently, ganglionectomy using application of laser speckle flow graph has been evaluated for the treatment of compensatory sweating. We report our results of ganglionectomy for facial blushing as a redo surgery. METHODS: Between August 2012 and April 2017, 8 patients with facial blushing who underwent an initial sympathectomy reported symptom recurrence. Seven patients had undergone transection of the sympathetic trunk at the second rib and 1 patient had undergone transection of the sympathetic trunk at the second and third ribs. These patients were treated using ganglionectomy guided by application of laser speckle flow graph. After temporary decreases in facial skin blood perfusion were confirmed by stimulating the sympathetic ganglions, ganglionectomy was performed. RESULTS: All patients' symptoms improved. There were no side effects, including deterioration of compensatory sweating, worsening of gustatory sweating, or Horner syndrome. There were no cases of mortality or conversion to open surgery. CONCLUSIONS: This study shows the effectiveness of ganglionectomy for the treatment of facial blushing, representing a new treatment option for this condition. Considering the mechanism of facial blushing, it is important to recognize that ganglionectomy is effective after the interception of the sympathetic trunk on the cranial side.

Loratadine augments emotional blushing.

The aim of this study was to determine whether loratadine, a selective inverse agonist of peripheral histamine H1 receptors, would reduce emotional blushing. Loratadine (10 mg) or placebo was administered orally one hour before 31 healthy participants sang a children's nursery rhyme to evoke embarrassment and blushing. Skin blood flow was monitored via a laser Doppler probe attached to the cheek. Increases in facial blood flow while participants sang were greater in the loratadine than the placebo group (mean increase ±â€¯standard deviation 71 ±â€¯52% in the loratadine group versus 35 ±â€¯37%, p = .036). However, perceptions of blushing were similar in both groups. These findings suggest that loratadine augmented blushing rather than inhibiting it. Thus, histamine released during blushing may inhibit acute increases in facial blood flow by evoking H1 receptor-mediated vasoconstriction.