The common cold is the most common acute respiratory tract infection. However, common cold is not “common”. According to domestic and international data, common cold can cause serious social and economic burdens, as well as serious complications, and even threaten patients’ lives and kill them. According to a survey on the current status and awareness of the common cold organized by the China Asthma Alliance and the China Center for Evidence-Based Medicine in 2010, there is a gap in clinicians’ awareness of the common cold, as well as duplication of medications, inappropriate combinations of medications, and misuse of antimicrobial and antiviral drugs in clinical practice. In order to further enhance clinicians’ correct understanding of the common cold, avoid the harm caused by improper treatment, and further improve the clinical diagnosis and treatment of the common cold in China, the Respiratory Physicians Branch of the Chinese Medical Doctors Association (CMPA) and the Emergency Physicians Branch of the Chinese Medical Doctors Association (CMPA) jointly organized relevant experts to conduct serious discussions, and with reference to domestic and international consensus and guidelines on the diagnosis and treatment of the common cold and relevant literature, drafted this consensus to standardize the diagnosis and treatment of the common cold. The consensus is to standardize the diagnosis and treatment of the common cold and to guide the correct and rational use of medication, so as to improve the diagnosis and treatment of the common cold and to reduce medical costs. Epidemiology and Disease Burden The average number of times a person suffers from the common cold is 2-6 times per year, and the average number of times a child suffers from the common cold is 6-8 times per year. The common cold can cause a great economic burden, according to the United States data show that 30% of the missed school days, 40% of the missed work is caused by the common cold, the common cold each year led to 2.3 billion days of missed school days, 2.5 billion days of missed work, each year due to the common cold 2.7 billion visits to the doctor, each year for the relief of the symptoms of the common cold cough and other over-the-counter medicines cost nearly 2 billion U.S. dollars, and antibacterial drugs cost 2.27 billion U.S. dollars. billion dollars. In addition, the treatment of complications and the worsening of the original disease cause a significant increase in health care costs and aggravate the burden of disease. Etiology and Pathophysiology (1) Etiology 1. Etiology: Most common colds are caused by viruses. Rhinovirus is the most common pathogen causing common colds, and other viruses include coronaviruses, parainfluenza viruses, respiratory syncytial viruses, etc. The most common cause of common colds is rhinovirus. 2. Risk factors: Risk factors for colds include seasonal changes, crowded environments, sedentary lifestyles, age, smoking, malnutrition, stress, excessive fatigue, insomnia, and low immunity. (ii) Pathophysiology When the virus reaches the glandular region of the pharynx, the virus binds specifically to the airway epithelial cells. The virus replicates in the epithelial cells and local lymphoid tissues of the respiratory tract, causing cytopathic and inflammatory reactions. Inflammatory mediators released after viral infection, including kinins, leukotrienes, IL-1, IL-6, IL-8, and TNF, lead to an increase in vascular permeability, which leads to plasma infiltration into the nasal mucosa, an increase in secretion by nasal glands, and respiratory symptoms such as clear runny nose and nasal congestion, as well as systemic symptoms, such as fever and generalized pain. Symptoms tend to appear within 16 h after the virus infects the organism and peak at 24-48 h. The peak of virus excretion is reached within 2-3 d. The virus can also be directly infected in the lower respiratory tract. The virus can also directly infect the lower respiratory tract, leading to related inflammatory reactions, inducing airway hyperresponsiveness and up-regulating the expression of adhesion molecules on the surface of bronchial epithelial cells, resulting in lower respiratory tract dysfunction. Clinical manifestations, often in the alternation of seasons and the onset of winter and spring, the onset of the disease is more acute, early symptoms mainly in the nose, mainly kata symptoms, there may be sneezing, nasal congestion, watery nasal discharge, there may be pharyngeal discomfort or dry throat, pharyngeal itching or burning sensation. 2-3 d after the thick snot, there may be pharyngolaryngolaryngolaryngolaryngolaryngolaryngitis or hissing, and sometimes due to the pharyngolaryngeal inflammation can appear hearing loss, but also can appear tearing, dull sense of taste, breathing, cough, cough and a small amount of sputum and other symptoms. Sometimes there may be hearing loss due to pharyngitis. Generally, there is no fever and systemic symptoms, or only low-grade fever. In severe cases, in addition to fever, there may be malaise, chills, aches and pains in the limbs, headache, loss of appetite and other systemic symptoms. The common cold without complications can be cured in 5-7 d. The elderly and children are susceptible to complications. Elderly people and children are prone to cold complications. If accompanied by underlying diseases, the clinical symptoms of the common cold are more severe and prolonged, and complications are likely to occur, prolonging the course of the disease. Physical examination reveals nasal mucosal congestion, edema, and secretions, mild pharyngeal congestion, and no abnormalities in the chest. Those with underlying diseases or complications can be detected with corresponding signs. Laboratory examination 1, peripheral blood picture: the total number of leukocytes is not high or low, the proportion of lymphocytes is relatively increased, and the total number of leukocytes and lymphocytes can be decreased in patients with severe diseases. 2.Virology examination: the virology examination of common cold is generally not carried out in clinic, and it is mainly used for epidemiological research. (1) Virus-specific antigen and its gene detection: take respiratory specimens from patients and use immunofluorescence or enzyme immunoassay to detect virus-specific nucleoprotein or matrix protein. RT-PCR can also be used to detect specific gene fragments encoding the cold virus. RT-PCR or real-time quantitative PCR is an early and sensitive diagnostic method, and the results can be obtained within 4-6 h. The results of RT-PCR or real-time quantitative PCR can be obtained in the early stage of diagnosis. (2) Virus isolation: isolate the virus from the patient’s respiratory specimens such as nasopharyngeal secretions, oral gargles, tracheal aspirates or lung specimens. Virus isolation is time-consuming and requires high laboratory skills, but it is a method of pathogenetic confirmation. (3) Serologic examination: 7d after the onset of the acute phase and 2-3 weeks after the recovery period to collect double serum for viral antibody determination, the latter antibody titer compared with the former 4 times or more than 4 times higher. V. Diagnosis and differential diagnosis (a) Diagnosis based on the common cold is mainly based on the typical clinical symptoms of diagnosis, and in the exclusion of other diseases under the premise of diagnosis. (B) Differential diagnosis 1, influenza (hereinafter referred to as influenza): the onset of acute, highly contagious, with systemic symptoms of intoxication, respiratory symptoms are mild. Elderly people and people with chronic respiratory diseases and heart disease are prone to complications of pneumonia. 2, acute bacterial sinusitis: the causative organisms are mostly Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus, Escherichia coli and Escherichia coli, etc., and mixed infections are mostly seen in the clinic. Symptoms are often aggravated after viral upper respiratory tract infections. The main symptoms are nasal congestion, increased purulent nasal discharge, decreased sense of smell and headache. Acute sinusitis patients may be accompanied by fever and generalized symptoms. 3, allergic rhinitis: seasonal and perennial, mostly in contact with allergens (such as pollen, etc.) symptoms, the main symptoms of paroxysmal sneezing, watery nasal discharge, after the attack, such as healthy people. Only nasal symptoms or fatigue, generally no fever and other systemic symptoms, and the course of the disease is long, perennial recurrence or seasonal aggravation. 4, streptococcal pharyngitis: the main causative organism is A-type beta-hemolytic streptococcus. Its symptoms are similar to viral pharyngitis, fever can last 3-5 d, all symptoms will be relieved in 1 week. It occurs in winter and spring seasons; it is dominated by pharyngeal inflammation, which may be accompanied by pharyngeal discomfort, itching, burning sensation, sore throat, etc. It may be accompanied by fever and malaise, etc.; on examination, there is obvious pharyngeal congestion and edema, and the submandibular lymph nodes are enlarged and have tenderness. The diagnosis of streptococcal pharyngitis mainly relies on the culture of pharyngeal swab or rapid antigen detection. 5, herpes pharyngitis: the onset of the season in the summer, common in children, occasionally seen in adults; sore throat degree is heavier, more accompanied by fever, the duration of the disease is about 1 week; there is pharyngeal congestion, soft palate, palatine, pharyngeal and tonsillar surfaces of grayish-white herpes and superficial ulceration, circumferentially with the encircling red halo; the virus isolation is mostly Coxsackie Virus A. Sixth, the treatment (a) the principle of treatment Due to colds at present there is no effective antiviral drugs. Therefore, symptomatic treatment and relief of cold symptoms should be the main focus, and attention should be paid to rest, proper supplementation of water, maintaining indoor air circulation, and avoiding secondary bacterial infections. (Appropriate rest, bed rest for patients with fever, severe condition or old and weak patients, smoking cessation, drinking plenty of water, light diet, maintaining nasal, pharyngeal and oral hygiene. Oral medication should be preferred for the treatment of cold and flu patients, and blind intravenous rehydration should be avoided. Intravenous rehydration is only applicable to the following situations: (1) the patient’s existing underlying diseases are aggravated due to the cold, or complications arise, requiring intravenous drug administration; (2) the patient needs to replenish water and electrolytes due to dehydration and electrolyte disorders caused by severe diarrhea or high fever; (3) the patient is unable to eat due to gastrointestinal discomfort and vomiting, and needs rehydration to maintain the body’s basal metabolism. (C) Drug treatment The drug treatment of common cold should be based on symptomatic drugs. The types of drugs commonly used in clinical practice are as follows: 1. Decongestants: these drugs can make the swollen nasal mucosa and sinuses of cold patients vasoconstriction, which can help to alleviate cold-induced nasal congestion, runny nose and sneezing and other symptoms. Pseudoephedrine selectively constricts blood vessels in the upper respiratory tract and has less effect on blood pressure, making it the most commonly used decongestant in patients with the common cold. Other vasoconstrictor drugs such as ephedrine, if used in excess, can lead to increased blood pressure, etc., and special attention should be paid. In addition to oral administration, these drugs can also be used directly as nasal drops or nasal spray, but generally should not be used continuously for more than 7d. 2. Antihistamines: these drugs have an anti-allergic effect, inhibit the dilatation of small blood vessels by blocking the histamine receptor to reduce vascular permeability, which can help to eliminate or alleviate the symptoms of sneezing and sneezing of patients with common colds. However, common adverse reactions to this class of drugs include drowsiness, fatigue, etc., and should be used with caution by workers in industries such as car and boat driving, ascent work or operation of precision instruments. First-generation antihistamines, such as chlorpheniramine maleate and diphenhydramine, have the ability to cross the blood-brain barrier, penetrate human central nerve cells and bind to histamine receptors. Because they have a certain degree of anticholinergic effect, they can help to reduce secretions and alleviate the symptoms of coughing, and are therefore recommended as the first choice of medicine for the common cold. Second-generation antihistamines, despite their non-drowsy, non-sedating virtues, do not suppress cough because of their lack of anticholinergic effect. Antihistamine nasal sprays have stronger local effects and fewer systemic adverse effects. 3, cough suppressant: commonly used cough suppressant according to its pharmacological role is divided into two categories: (1) central cough suppressant: morphine alkaloids and their derivatives. This kind of drug directly inhibits the medulla oblongata cough center and produces cough suppressant effect. According to whether it is addictive and anesthesia can be divided into two categories: dependent and non-dependent. Dependent cough suppressants: codeine, for example, can directly inhibit the medullary center, cough suppressant effect is strong and rapid, and has analgesic and sedative effects. Because of the addictive properties, only in the other treatment is ineffective for a short period of time to use. ② non-dependent cough suppressants: mostly synthetic cough suppressants. Such as dextromethorphan, is currently the most widely used clinical cough suppressant, the effect is similar to codeine, but no analgesic and sedative effect, the therapeutic dose of the respiratory center has no inhibitory effect, there is no addiction. A variety of non-prescription compound cough suppressants contain this product. (2) peripheral cough suppressant: through the inhibition of the cough reflex arc in the receptors, afferent nerves and effectors in a link and play a role in cough suppression. These drugs include local anesthetics and mucosal protective agents. ①Narcotics: isoquinoline alkaloids contained in opioids, with effects comparable to those of codeine, no dependence, and no inhibitory effect on the respiratory center. It is suitable for coughs caused by different reasons. ② phenylpropylpiperine: non-narcotic cough suppressant, can inhibit the peripheral afferent nerve, can also inhibit the cough center. 4, expectorant drugs: expectorant therapy can improve the clearance rate of airway secretion cough. The mechanism of expectorant drugs include: increase the amount of secretion discharge, reduce the viscosity of secretion, increase the clearance function of cilia. Commonly used expectorants include guaiacol glyceryl ether, ambroxol, bromoacetin, acetylcysteine, carbocysteine, etc. Among them, guaiacol glyceryl ether is a commonly used ingredient of compound cold medicines, which can stimulate the gastric mucosa, reflexively cause the increase of airway secretion, reduce the degree of mucus, and have a certain diastolic bronchial effect, to achieve the effect of increasing mucus discharge. Often used in conjunction with antihistamines, cough suppressants, decongestants. 5, antipyretic and analgesic drugs: mainly for common cold patients with fever, sore throat and generalized pain and other symptoms. This kind of drugs such as acetaminophen, ibuprofen, etc., through the reduction of prostaglandin synthesis, so that the thermoregulatory center produces peripheral vasodilatation, sweating and dissipation of heat to play the role of antipyretic, through the blockade of the impulse of the nociceptive nerve endings and produce analgesic effect. Acetaminophen is one of the more commonly used drugs, but it should be noted that acetaminophen overdose may cause liver injury or even liver necrosis. Ibuprofen has been reported to increase the severity of infection. Most of the cold and flu medicines currently available in the market are compound preparations containing two or more ingredients from each of the above types of medicines or from other medicines, as shown in Table l (see Annex). Although there are many varieties of drugs for treating cold and flu, with different names, the ingredients of their formulations are the same or similar, and the effects of the drugs are very similar, so the compound anti-cold and flu medicines should be selected only one of them, such as taking more than two kinds of medicines at the same time, which can lead to repeated use of medicines, overdosage, and increase the incidence of the adverse reactions of the above medicines. Some research data show that the early only nasal symptoms of cold and flu patients, taking pseudoephedrine hydrochloride and paracetamol on the first day, nasal congestion, runny nose, sneezing, tearing symptoms have improved, after 4d of the above symptomatic improvement have reached about 90%, indicating that this combination can rapidly improve or eliminate nasal symptoms. Therefore, pseudoephedrine and paracetamol are recommended as a classic combination for the treatment of early colds with only nasal symptoms. When symptoms such as cough, body aches and fever are present on top of nasal symptoms, it is recommended to take cold medicines containing cough suppressants and antipyretic ingredients.