Blushing is generally distinguished, despite a close physiological relation, from flushing, which is more intensive and extends over more of the body, and seldom has a mental source. If redness persists for abnormal amounts of time after blushing, then it may be considered an early sign of rosacea. Idiopathic craniofacial erythema is a medical condition where a person blushes strongly with little or no provocation. Just about any situation can bring on intense blushing and it may take one or two minutes for the blush to disappear. Severe blushing can make it difficult for the person to feel comfortable in either social or professional situations. People who have social phobia are particularly prone to idiopathic craniofacial erythema. Psychological treatments and medication can help control blushing.

Some people are very sensitive to emotional stress. Given a stimulus such as embarrassment, the person's sympathetic nervous system will cause blood vessels to open wide, flooding the skin with blood and resulting in reddening of the face. In some people, the ears, neck and upper chest may also blush. As well as causing redness, blushing can sometimes make the affected area feel hot.

"Erythrophobia" is the fear of blushing, from and literally "fear of redness".

There is evidence that the blushing region is anatomically different in structure. The facial skin, for example, has more capillary loops per unit area and generally more vessels per unit volume than other skin areas. In addition, blood vessels of the cheek are wider in diameter, are nearer the surface, and visibility is less diminished by tissue fluid. These specific characteristics of the architecture of the facial vessels led Wilkin in an overview of possible causes of facial flushing to the following conclusion: "[...] increased capacity and greater visibility can account for the limited distribution of flushing".

Evidence for special vasodilation mechanisms was reported by Mellander and his colleagues (Mellander, Andersson, Afzelius, & Hellstrand. 1982). They studied buccal segments of the human facial veins in vitro. Unlike veins from other areas of the skin, facial veins responded with an active myogenic contraction to passive stretch and were therefore able to develop an intrinsic basal tone. Additionally Mellander et al. showed that the veins in this specific area were also supplied with beta-adrenoceptors in addition to the common alpha-adrenoceptors. These beta-adrenoceptors could exert a dilator mechanism on the above-described basal tone of the facial cutaneous venous plexus. Mellander and his colleagues propose that this mechanism is involved in emotional blushing. Drummond has partially confirmed this effect by pharmacological blocking experiments (Drummond. 1997). In a number of trials, he blocked both alpha-adrenergic receptors (with phentolamine) and beta-adrenergic receptors (with propranolol introduced

transcutaneously by iontophoresis). Blushing was measured at the forehead using a dual channel laser Doppler flowmeter. Subjects were undergraduate students divided into frequent and infrequent blushers according to self-report. Their mean age was 22.9 years, which is especially favorable for assessing blushing, since young subjects are more likely to blush and blush more intensively. The subjects underwent several procedures, one of which was designed to produce blushing. Alpha-adrenergic blockade with phentolamine had no influence on the amount of blushing in frequent or in infrequent blushers, indicating that release of sympathetic vasoconstrictor tone does not substantially influence blushing. This result was expected since vasoconstrictor tone in the facial area is known to be generally low (van der Meer. 1985). Beta-adrenergic blockade with propranolol on the other hand decreased blushing in both frequent and infrequent blushers. However, despite complete blockade, blood flow still increased

substantially during the embarrassment and blushing inducing procedure. Additional vasodilator mechanisms must therefore be involved.

When someone starts to feel the sensation of being scared or nervous they start to experience anxiety. According to a Harvard Mental Health Letter, "Anxiety usually has physical symptoms that may include a racing heart, a dry mouth, a shaky voice, blushing, trembling, sweating, lightheadedness, and nausea". It triggers the body to activate its sympathetic nervous system. This process takes place when the body releases adrenaline into the blood stream causing a chain of reactions to occur. This bodily response is known as the "fight or flight" syndrome, a naturally occurring process in the body done to protect itself from harm. "The neck muscles contract, bringing the head down and shoulders up, while the back muscles draw the spine into a curve. This, in turn, pushes the pelvis forward and pulls the genitals up, slumping the body into a classic fetal position".

In trying to resist this position, the body will begin to shake in places such as the legs and hands. Several other things happen besides this. Muscles in the body contract, causing them to be tense and ready to attack. Second, "blood vessels in the extremities constrict". This can leave a person with the feeling of cold fingers, toes, nose, and ears. Constricted blood vessels also gives the body extra blood flow to the vital organs.

In addition, those experiencing stage fright will have an increase in blood pressure, which supplies the body with more nutrients and oxygen in response to the "fight or flight" instincts. This, in return, causes the body to overheat and sweat. Breathing will increase so that the body can obtain the desired amount of oxygen for the muscles and organs. Pupils will dilate giving someone the inability to view any notes they have in close proximity; however, long range vision is improved making the speaker more aware of their audience's facial expressions and nonverbal cues in response to the speaker's performance. Lastly, the digestive system shuts down to prepare for producing energy for an immediate emergency response. This can leave the body with the effects of dry mouth, nausea, or butterflies.

Though scopophobia is a solitary disorder, many individuals with scopophobia also commonly experience other anxiety disorders. Scopophobia has been related to many other irrational fears and phobias. Specific phobias and syndromes that are similar to scopophobia include erythrophobia, the fear of blushing (which is found especially in young people), and an epileptic's fear that being looked which may itself precipitate such an attack. Scopophobia is also commonly associated with schizophrenia and other psychiatric disorders. It is not considered indicative of other disorders, but is rather considered as a psychological problem that may be treated independently.

Sociologist Erving Goffman suggested that shying away from casual glances in the street remained one of the characteristic symptoms of psychosis in public. Many scopophobia patients develop habits of voyeurism or exhibitionism. Another related, yet very different syndrome, scopophilia, is the excessive enjoyment of looking at erotic items.

Stage fright may be observed in people of all experiences and backgrounds, from those who are completely new to being in front of an audience to those who have done so for years. It is commonly known among everyday people and may, for example, affect their confidence in job interviews. It also affects actors, comedians, musicians, and politicians. Many people with no other problems in communication can experience stage fright, but some people with chronic stage fright also have social anxiety or social phobia which are chronic feelings of high anxiety in any social situation. Stage fright can also be seen in school situations, like stand up projects and class speeches.

At a low level, anxiety is not a bad thing. In fact, the hormonal response to anxiety has evolved as a benefit, as it helps humans react to dangers. Researchers in evolutionary medicine believe this adaptation allows humans to realize there is a potential threat and to act accordingly in order to ensure greatest possibility of protection. It has actually been shown that those with low levels of anxiety have a greater risk of death than those with average levels. This is because the absence of fear can lead to injury or death. Additionally, patients with both anxiety and depression were found to have lower morbidity than those with depression alone. The functional significance of the symptoms associated with anxiety includes: greater alertness, quicker preparation for action, and reduced probability of missing threats. In the wild, vulnerable individuals, for example those who are hurt or pregnant, have a lower threshold for anxiety response, making them more alert. This demonstrates a lengthy evolutionary history of the anxiety response.

GAD runs in families and is six times more common in the children of someone with the condition.

While anxiety arose as an adaptation, in modern times it is almost always thought of negatively in the context of anxiety disorders. People with these disorders have highly sensitive systems; hence, their systems tend to overreact to seemingly harmless stimuli. Sometimes anxiety disorders occur in those who have had traumatic youths, demonstrating an increased prevalence of anxiety when it appears a child will have a difficult future. In these cases, the disorder arises as a way to predict that the individual’s environment will continue to pose threats.

Scopophobia is unique among phobias in that the fear of being looked at is considered both a social phobia and a specific phobia, because it is a specific occurrence which takes place in a social setting. Most phobias typically fall in either one category or the other but scopophobia can be placed in both. On the other hand, as with most phobias, scopophobia generally arises from a traumatic event in the person's life. With scopophobia, it is likely that the person was subjected to public ridicule as a child. Additionally, a person suffering from scopophobia may often be the subject to public staring, possibly due to a deformity or physical ailment.

According to the Social Phobia/Social Anxiety Association, U.S. government data for 2012 suggests that social anxiety affects over 7% of the population at any given time. Stretched over a lifetime, the percentage increases to 13%.

A number of treatments are available. The most successful non-invasive procedure is cognitive behavioural therapy (CBT), which attempts to alleviate the anxiety felt by sufferers.

In extreme cases a surgical procedure known as endoscopic transthoracic sympathicotomy (ETS) is available. Pioneered by surgeons in Sweden, this procedure has recently become increasingly controversial due to its many potential adverse effects. Patients who have undergone the procedure frequently complain of compensatory sweating and fatigue, with around 5% reconsidering getting the treatment. ETS is now normally only considered in extreme cases where other treatments have been ineffective.

Typically, this disease is presaged by a childhood history of social inhibition and shyness. It is possible that it could result from a humiliating traumatic experience, or it could emerge from a lifelong onset of the illness that only comes to the surface after time.

Clinical data indicates that more males have the condition than females, despite the fact that females scored higher on a social phobia scale than men, and report higher scores on proclivity towards feelings of embarrassment. This differs from Western society where the prevalence of females with social phobias is to some extent greater than that of males. The lifetime prevalence of the disorder falls anywhere between 3% and 13% with changes in severity occurring throughout one's lifetime. It is estimated that about 17% of individuals with taijin kyofusho have fears of releasing foul body odor.

Social anxiety disorder is known to appear at an early age in most cases. Fifty percent of those who develop this disorder have developed it by the age of 11, and 80% have developed it by age 20. This early age of onset may lead to people with social anxiety disorder being particularly vulnerable to depressive illnesses, drug abuse and other psychological conflicts.

When prevalence estimates were based on the examination of psychiatric clinic samples, social anxiety disorder was thought to be a relatively rare disorder. The opposite was found to be true; social anxiety was common, but many were afraid to seek psychiatric help, leading to an underrecognition of the problem.

The National Comorbidity Survey of over 8,000 American correspondents in 1994 revealed 12-month and lifetime prevalence rates of 7.9 percent and 13.3 percent, respectively; this makes it the third most prevalent psychiatric disorder after depression and alcohol dependence, and the most common of the anxiety disorders. According to U.S. epidemiological data from the National Institute of Mental Health, social phobia affects 15 million adult Americans in any given year. Estimates vary within 2 percent and 7 percent of the U.S. adult population.

The mean onset of social phobia is 10 to 13 years. Onset after age 25 is rare and is typically preceded by panic disorder or major depression. Social anxiety disorder occurs more often in females than males. The prevalence of social phobia appears to be increasing among white, married, and well-educated individuals. As a group, those with generalized social phobia are less likely to graduate from high school and are more likely to rely on government financial assistance or have poverty-level salaries. Surveys carried out in 2002 show the youth of England, Scotland, and Wales have a prevalence rate of 0.4 percent, 1.8 percent, and 0.6 percent, respectively. In Canada, the prevalence of self-reported social anxiety for Nova Scotians older than 14 years was 4.2 percent in June 2004 with women (4.6 percent) reporting more than men (3.8 percent). In Australia, social phobia is the 8th and 5th leading disease or illness for males and females between 15–24 years of age as of 2003. Because of the difficulty in separating social phobia from poor social skills or shyness, some studies have a large range of prevalence. The table also shows higher prevalence in Sweden.

It has been shown that there is a two to threefold greater risk of having social phobia if a first-degree relative also has the disorder. This could be due to genetics and/or due to children acquiring social fears and avoidance through processes of observational learning or parental psychosocial education. Studies of identical twins brought up (via adoption) in different families have indicated that, if one twin developed social anxiety disorder, then the other was between 30 percent and 50 percent more likely than average to also develop the disorder. To some extent this 'heritability' may not be specific – for example, studies have found that if a parent has any kind of anxiety disorder or clinical depression, then a child is somewhat more likely to develop an anxiety disorder or social phobia. Studies suggest that parents of those with social anxiety disorder tend to be more socially isolated themselves (Bruch and Heimberg, 1994; Caster et al., 1999), and shyness in adoptive parents is significantly correlated with shyness in adopted children (Daniels and Plomin, 1985).

Growing up with overprotective and hypercritical parents has also been associated with social anxiety disorder. Adolescents who were rated as having an insecure (anxious-ambivalent) attachment with their mother as infants were twice as likely to develop anxiety disorders by late adolescence, including social phobia.

A related line of research has investigated 'behavioural inhibition' in infants – early signs of an inhibited and introspective or fearful nature. Studies have shown that around 10–15 percent of individuals show this early temperament, which appears to be partly due to genetics. Some continue to show this trait into adolescence and adulthood, and appear to be more likely to develop social anxiety disorder.

Idiopathic craniofacial erythema is a medical condition characterised by severe, uncontrollable, and frequently unprovoked, facial blushing.

Blushing can occur at any time and is frequently triggered by even mundane events, such as, talking to friends, paying for goods in a shop, asking for directions or even simply making eye contact with another person.

For many years, the cause of the condition was thought to be an anxiety problem, caused by a mental health disorder. However, in recent years experts in the field of the disorder believe it to be caused by an overactive sympathetic nervous system, an automatic response which sufferers have no mental control over. It is related to focal hyperhidrosis, more commonly known as excessive sweating, as it is caused by the same overactive nerves which cause excessive sweating. Sufferers of severe facial blushing commonly experience focal hyperhidrosis. Studies have also shown that patients with severe facial blushing or focal hyperhidrosis commonly have family members with one or both of the related disorders.

Taijin kyofusho (対人恐怖症 taijin kyōfushō, TKS, for "taijin kyofusho symptoms") is a Japanese culture-specific syndrome. The term taijin kyofusho translates into the disorder (sho) of fear (kyofu) of interpersonal relations (taijin). Those who have taijin kyofusho are likely to be extremely embarrassed of themselves or fearful of displeasing others when it comes to the functions of their bodies or their appearances. These bodily functions and appearances include their faces, odor, actions, or even looks. They do not want to embarrass other people with their presence. This culture-bound syndrome is a social phobia based on fear and anxiety.

The symptoms of this disorder include avoiding social outings and activities, rapid heartbeat, shortness of breath, panic attacks, trembling, and feelings of dread and panic when around people. The causes of this disorder are mainly from emotional trauma or psychological defense mechanism. It is more common in men than women. Lifetime prevalence is estimated at 3–13%.

In 2009, a study investigated the impact of anthropophobia in specific cultures. 50 patients diagnosed with anthropophobia, 50 patients diagnosed with neurasthenia, and 50 control subjects were recruited from hospitals in Beijing, China. Measures of anthropophobic and anxiety symptoms were administered to the subjects. The patients with anthropophobia could not even make eye contact with others and were afraid of being watched. The conclusion drawn was that anthropophobics, like neurasthenics, experience anxiety and depression, but "more cognitively and less somatically".

Anthropophobia or Anthrophobia (literally "fear of humans", from , "ánthropos", "human" and , "phóbos", "fear"), also called interpersonal relation phobia or social phobia, is pathological fear of people or human company.

Anthropophobia is an extreme, pathological form of shyness and timidity. Being a form of social phobia, it may manifest as fears of blushing or meeting others' gaze, awkwardness and uneasiness when appearing in society, etc. A specific Japanese cultural form is known as taijin kyofusho.

Anthropophobia can be best defined as the fear of people in crowded situations, but can also go beyond and leave the person uncomfortable when being around just one person. Conditions vary depending on the person. Some cases are mild and can be handled while more serious cases can lead to complete social withdrawal and the exclusive use of written and electronic communication.

For a person to flush is to become markedly red in the face and often other areas of the skin, from various physiological conditions. Flushing is generally distinguished, despite a close physiological relation between them, from blushing, which is milder, generally restricted to the face, cheeks or ears, and generally assumed to reflect emotional stress, such as embarrassment, anger, or romantic stimulation. Flushing is also a cardinal symptom of carcinoid syndrome—the syndrome that results from hormones (often serotonin or histamine) being secreted into systemic circulation.

Commonly referred to as the sex flush, vasocongestion (increased blood flow) of the skin can occur during all four phases of the human sexual response cycle. Studies show that the sex flush occurs in approximately 50–75% of females and 25% of males, yet not consistently. The sex flush tends to occur more often under warmer conditions and may not appear at all under lower temperatures.

During the female sex flush, pinkish spots develop under the breasts, then spread to the breasts, torso, face, hands, soles of the feet, and possibly over the entire body. Vasocongestion is also responsible for the darkening of the clitoris and the walls of the vagina during sexual arousal. During the male sex flush, the coloration of the skin develops less consistently than in the female, but typically starts with the epigastrium (upper abdomen), spreads across the chest, then continues to the neck, face, forehead, back, and sometimes, shoulders and forearms.

The sex flush typically disappears soon after reaching orgasm, but in other cases it may take up to two hours or so, and sometimes intense sweating occurs simultaneously.

Gelotophobia is a fear of being laughed at, a type of social phobia. While most people do not like being laughed at, there is a sub-group of people that exceedingly fear being laughed at. Without obvious reasons, they relate laughter they hear to be directed at themselves. Since 2008, this phenomenon has attracted attention from scholars in psychology, sociology, and psychiatry, and has been studied intensively.

In his clinical observations, found that some of his patients seemed to be primarily worried about being laughed at. They tended to scan their environment for signs of laughter and ridicule. Furthermore, they reported that they had the impression of being ridiculous themselves. Additionally, Titze observed a specific movement pattern among them when they thought they were being laughed at—awkward, wooden movements that resembled those of wooden puppets. He described this state as “Pinocchio-syndrome”.

Two other behaviours related to laughter are gelotophilia - "the joy of being laughed at" and katagelasticism - "the joy of laughing at others".

Women, especially those who are menopausal, are more likely than men to develop rosacea.

About 65% of persons with CH are, or have been, tobacco smokers. Stopping smoking does not lead to improvement of the condition and CH also occurs in those who have never smoked (e.g. children); it is thought unlikely that smoking is a cause. People with CH may be predisposed to certain traits, including smoking or other lifestyle habits.

Cluster headache may, but rarely, run in some families in an autosomal dominant inheritance pattern. People with a first degree relative with the condition are about 14–48 times more likely to develop it themselves, and between 1.9 and 20% of persons with CH have a positive family history. Possible genetic factors warrant further research, current evidence for genetic inheritance is limited.

Of people that have a sympathectomy, it is impossible to predict who will end up with a more severe version of this disorder, as there is no link to gender, age or weight. There is no test or screening process that would enable doctors to predict who is more susceptible.

From the clinical observations a model of the causes and consequences of gelotophobia was drawn up so that the condition could be studied scientifically. The model claims that gelotophobia can be caused by any one of three things at different stages of development:

The putative causes of gelotophobia:

- In infancy: development of primary shame failure to develop an interpersonal bridge (e.g. unsupportive infant–caregiver interactions).

- In childhood & youth: repeated traumatic experiences of not being taken seriously or being laughed at/ridiculed (e.g. bullying).

- In adulthood: intense traumatic experience of being laughed at or ridiculed (e.g. ).

The consequences of gelotophobia:

- Social withdrawal to avoid being ridiculed.

- Appearing ‘cold as ice’/humourless.

- Psychosomatic disturbances, e.g. blushing, tension headache, trembling, dizziness, sleep disturbances.

- Demonstrating ‘Pinocchio Syndrome:’ clumsy, ‘agelotic’ face, ‘wooden puppet' appearance.

- Lack of liveliness, spontaneity, joy.

- Inability to experience humour/laughter as relaxing and joyful social experiences.

- Anger when being laughed at by other people (in some cases this results in violent attacks on the people who were laughing).

Later this model was revised and expanded.

In 2007, Richard Gallo and colleagues noticed that patients with rosacea had high levels of the antimicrobial peptide cathelicidin and elevated levels of stratum corneum tryptic enzymes (SCTEs). Antibiotics have been used in the past to treat rosacea, but they may only work because they inhibit some SCTEs.