Hypertrichosis is a symptom of sympathetic chain syndrome. Skin irritation, such as increased sweating and hypertrichosis, may occur. Sympathetic chain syndrome is a long-standing, insidious clinical syndrome with multiple etiologies. Typical symptoms appear when ganglion damage is severe and compensatory capacity is weakened, and are often delayed and discovered incidentally at autopsy. The clinical manifestations vary depending on the damaged sympathetic ganglion, but all have common clinical symptoms. Such as pain, sensory disturbance, and vascular dysfunction. The vegetative nerve function examination method for hyperreflexia of the standing hair: (1) eye-centered reflex Lie on your back with your eyes closed, use your fingers to lightly press both sides of one of the patient’s eyeballs, and after 3-4 seconds (with mild pain) start counting the pulse (count 15 seconds), record the number of pulses per minute, and compare it with the number of pulses before the examination. It may decrease by 4-7 beats/min after the examination in normal people. If the patient decreases by 12 beats/min or more, it is positive, indicating increased vagal tone; if it decreases by 18 to 24 beats/min or more, vagal tone is significantly increased. Such patients are particularly prone to syncope and have the possibility of cardiac arrest during treatment. In addition to a slowed heart rate, the pulse force is often reduced. Clinically, there may be blackness in front of the eyes, dizziness, nausea and even vomiting, which is usually called vagal tone. Conversely, if the pulse increases instead after pressure on the eyeball, it is called an inversion reaction, indicating that the patient has increased sympathetic tone. (2) White streak syndrome A white streak appears within 8 to 20 seconds when the skin is lightly and quickly scratched with a bamboo stick or nail (the lower limbs are more obvious) and lasts for 3 to 5 minutes. This is due to neurological reflexes that cause vasoconstriction, indicating increased sympathetic excitability. (3) Red streak syndrome Slight pressure with a bamboo stick across the skin, normal red streaks appear in 3 to 5 seconds, lasting 8 to 30 minutes. If the red stripe is wider and lasts longer, it may be related to increased parasympathetic excitability. In severe cases, it can appear only after 1 to 2 minutes of scratching the skin and lasts for 1 to 12 hours. The skin elevation and edema at the scratching area are caused by vasodilatation and blood exudation. Skin scratching can also occur in normal people, but only if it lasts too long, or if a reaction occurs regardless of light or heavy scratching, does it have clinical reference significance. (4) Prone and standing test: Have the patient lie down and count the pulse for 1 minute; then sit up and count the pulse for 1 minute. If the pulse increases by 10-20 beats/min from the prone to the standing position, the sympathetic excitability is increased; if the pulse decreases by 10-20 beats/min from the standing to the prone position, the parasympathetic excitability is increased. (5) Vertical hair reflex When an ice cube or other cold stimulus is placed on the skin of the back of the neck or axilla for a few seconds, the vertical hair muscle is seen to contract and the skin follicles are raised in a chicken skin-like appearance. This reflex is innervated by sympathetic nerve segments, and according to the response of different sites, sympathetic nerve dysfunction can be diagnosed locally. For example, C8-T3 innervates the head, face and neck, T4-7 innervates the upper extremities, T8-9 innervates the trunk, and T10-L2 innervates the lower extremities. (6) Microsweat determination method There is a correlation between skin humidity and the function of sweat glands. Warm sweating is mainly related to the ambient temperature and can regulate the body temperature. Neurogenic sweating is mainly controlled by the function of plant nerves. Sweat glands are innervated by the postganglionic fibers of cholinergic sympathetic nerves. By monitoring the neurogenic microsweat secretion of the skin, the sympathetic tension can be determined in time. (7) Micro nerve electrode method A silicon-carbon micro nerve electrode with a tip diameter of 0.1μ can be inserted into a single nerve cell and amplified by an electronic instrument in an environment shielded by a copper mesh to directly elicit the impulse issuance of sympathetic nerves. This is one of the most direct methods to determine sympathetic nerve function. (8) Diagnostic sympathetic block is the most commonly used method in clinical practice. Selective blockade of the sympathetic nerve innervating the lesion site, if the pain is rapidly relieved after the block, the diseased area changes from cold and moist to a comfortable warm feeling, the facial skin temperature increases and sweating decreases; it indicates that the occurrence of the pain is closely related to the sympathetic nerve. (9) Other ECG R2R interval method, determination of hormone concentration in blood, etc.