Definition: Acute infectious rhinosinusitis is defined as an acute infection of the mucous membranes of the nasal cavity and sinuses caused by pathogenic microorganisms such as viruses and bacteria, with symptoms persisting for no more than 12 weeks or pus accompanied by high fever (temperature ≥39°C) lasting for at least 3 d, provided that fever caused by other factors (especially lower respiratory tract infections) has been excluded. The prevalence of acute infectious rhinosinusitis is as high as 5% to 6% due to the prevalence of common colds in childhood and the influence of air pollution and other factors. Nasal-sinusitis is known to be associated with Kartagener’s syndrome, and severe infectious rhinosinusitis is also closely related to periorbital cellulitis and intracranial infections. More recent studies have shown that rhinosinusitis is associated with chronic cough in children, which used to be called postnasal drip syndrome (PNDS) and is now renamed as upper airway cough syndrome (UACS), one of the causes of which is rhinosinusitis. Clinical 1, the main symptoms: nasal congestion, mucus (pus) nasal discharge, facial pain or headache, severe cases are often accompanied by fever. Symptoms: the younger the more obvious systemic symptoms, viral rhinosinusitis, nasal infection symptoms generally within 10 d relief; bacterial symptoms usually last more than 10 d without improvement, and in the early stage of the disease more serious symptoms, including pus runny nose, high fever (temperature ≥ 39 ° C) and headache and so on. 2.Signs: congestion and swelling of the mucous membrane of the turbinate, mucous (pus) secretion in the nasal cavity and nasal passages, mucous (pus) secretion adhering to the posterior wall of the pharynx, and pressure and pain in the sinus area of the face. 3.Nasal endoscopy: it is an important means of diagnosis, applicable to children of any age. Microscopically, the mucous membrane of the inferior nasal cavity is congested and enlarged, and there are mucous or purulent secretions on the surface of the common nasal passage, the floor of the nose, the posterior nostrils and the inferior turbinate, which are mostly originated from the middle nasal passage or the olfactory fissure, and the adenoids can be seen to be enlarged in some of the patients. Sinus CT scan CT scan shows sinonasal complex or sinus mucosal lesions. CT scanning of the sinuses is not routinely recommended, especially in younger children (<6 years of age), but may be considered: (1) in patients with signs of complications such as intracranial, intraorbital, or soft-tissue abscesses; (2) in patients who do not respond well to a course of adequate antimicrobial medications; (3) in patients with recurrent episodes of disease; and (4) in patients suspected of having benign or malignant neoplastic organisms in the naso-sinus area. The gold standard for diagnosing acute bacterial sinusitis is the concentration of bacterial flora in sinus puncture fluid ≥10,000 units/mL, however, this microbial sample needs to be extracted by sinus puncture, which lacks operability in clinical practice and is not listed as a routine means of examination of children's rhinosinusitis, however, bacteriological examination is required for the following cases: (1) severe condition, even toxic symptoms; (2) no improvement in the treatment of antimicrobial drugs for 48～72 h; (3) suspected benign or malignant new organisms in the nose-sinus department. (2) those who do not improve after 48～72 h of antimicrobial treatment; (3) those who have immunodeficiency; (4) those who have intraorbital or intracranial complications. Treatment: Acute infectious rhinosinusitis in children is mainly treated conservatively with drugs and comprehensive treatment, according to its relative importance in the following order. 1, Antimicrobial drugs. Acute primary or secondary infectious rhinosinusitis due to bacteria, fungi, and atypical microorganisms has indications for the use of antimicrobial drugs. Common bacterial pathogens of rhinosinusitis include Streptococcus pneumoniae, Haemophilus influenzae, and Catamonas. According to domestic and international guidelines, literature reports and clinical practice experience, it is recommended to use oral amoxicillin-clavulanic acid 7:1 preparation, each dose (according to amoxicillin) 30-45 mg/kg, twice a day, the course of treatment for at least 10-14 d. Or choose macrolide antibiotics, such as oral azithromycin, azithromycin, each dose of 10 mg/kg, once a day, the course of treatment for 3-5 d. The total dose of treatment should not exceed 1500 mg/kg, and the total dose of treatment should not be more than 1500 mg/kg, and the total dose of treatment should not be more than 1500 mg/kg. Azithromycin has the advantages of high tissue concentration at the site of rhinosinus infection, short duration of treatment, long duration of action, good compliance, and it is also suitable for penicillin allergy. For those who are resistant to first-line drugs, 2nd or 3rd generation cephalosporins may be used. Effective and safe is the first principle of choosing antimicrobial drugs, nose - sinusitis with the use of antimicrobial drug indications should be given orally as the main route, do not emphasize the combined use of antimicrobial drugs. High fever, toxic symptoms, combined with intraorbital or local soft tissue abscess, vomiting caused by drug intake difficulties, etc. can choose the intravenous route to use the above antibacterial drugs. 2.Nasal glucocorticoid. Nasal glucocorticoid has anti-inflammatory, anti-edema effect, especially for the more serious symptoms of acute rhinosinusitis can relieve the symptoms, nasal glucocorticoid application in the morning spray is good, the course of treatment for 2 to 4 weeks. 3.Nasal rinsing. The use of saline or hypertonic saline or physiological seawater rinsing nasal cavity, can effectively relieve the acute stage of nasal mucosal edema, stimulate the activity of nasal mucosal cilia, increase the rate of clearance of nasal secretions, and can alleviate the clinical symptoms and improve the quality of life of children . Depending on the compliance of patients of different ages, rinsing, dripping or nebulization can be chosen. Its usage is 3 to 4 times a day for 2 weeks. 4, Antihistamines and leukotriene receptor antagonists. A considerable portion of children with acute infectious rhinosinusitis, there are clear allergic factors, especially with allergic rhinitis, can be systemic or nasal local use of the second generation of antihistamines, nasal antihistamines are preferred, but also oral leukotriene receptor antagonists, the course of treatment is generally not less than 2 weeks. For patients with asthma, oral leukotriene receptor antagonists are preferred. 5.Mucus promoting agent. Mucus promoter can dilute respiratory mucus and improve ciliary activity, mainly used in the chronic phase, but also effective in the acute phase, recommended for use, the course of treatment at least 4 weeks. 6, Nasal decongestant. For acute severe nasal obstruction, can be appropriate intermittent, short time (7 d or less) using low concentration of nasal mucosal decongestant, is conducive to lifting the obstruction of sinus drainage channels, improve nasal ventilation and drainage. Low concentrations of ephedrine (0.5%) or hydroxymetazoline hydrochloride are recommended, and the use of naphazoline hydrochloride (nasal drops) is prohibited. Assessment of efficacy The effectiveness of conservative drug treatment requires systematic evaluation and further management options, but children are limited by age and may have uncertainty in describing symptoms and feelings, so a comprehensive assessment should be made based on the complaints of the child and/or guardian, combined with the findings of the rhinoscopy. The efficacy assessment is formulated and selected with reference to domestic and international literature and the clinical practice experience of senior experts in China, and is assessed every 2 to 4 weeks for not less than 3 months. 1, subjective assessment. The quantitative assessment of children's symptoms is recommended to use visual analogue scale (VAS), which classifies their condition into mild, moderate, and severe subjective evaluation, and the Chinese translation of the specific condition classification table refers to the "Recommendations for the Diagnosis and Treatment of Children's Rhinosinusitis (2012, Kunming)". If the subjective judgment of VAS >5 points, the symptoms are more serious, indicating that the patient’s quality of life is affected, and the quality of life needs to be assessed. Table 1 is the quality of life assessment scale (suitable for children aged 4-18 years old), and in the assessment, the children’s ability to understand and express themselves needs to be combined with the parents’ opinions. 2. Objective assessment. Table 2 shows the “objective quantitative assessment of nasal endoscopy table” is the use of Lund-Kennedy scoring method and the combination of clinical experience of domestic experts for children’s acute rhinosinusitis to develop an objective scoring method; 1 to 3 for mild, 4 to 7 for moderate, 8 to 10 for severe. Scoring criteria: nasal congestion: 0=none, 1=mild, 2=severe; turbinate edema: 0=none, 1=mild, 2=severe; rhinorrhea pharyngeal: 0=none, 1=clear, thin rhinorrhea, 2=viscous, purulent rhinorrhea; middle passage accumulation of slugs: 0=none, 1=mild, 2=serious; slug crusts: 0=none, 1=mild, 2=serious. (0-10 per side, total score 0-20). Subjective and objective assessment of the child was carried out periodically according to the above quantitative scale, which allowed for uninterrupted fine-tuning of the treatment program with a view to early cure.