Pediatric genital tract infections include vulvovaginitis and internal genital inflammation, mainly vulvovaginitis, which can be caused by a variety of reasons, such as trauma, pathogenic infection or physicochemical factors, etc. It accounts for about 40% to 50% of pediatric gynecological outpatient cases and is the most common disease in pediatric gynecology. Inflammation of the internal genitalia is extremely rare, mainly seen in adolescents with a history of sexual intercourse, and is associated with untimely diagnosis and treatment of vulvovaginitis. Yang Dan et al [found that 25.0% of genital tract infections can form pelvic masses. 1. Susceptibility factors of vulvovaginitis in pediatric patients 1.1 Susceptibility factors of prepubertal vulvovaginitis: (1) Anatomical features: vulva lacks fat pad and pubic hair, vulvovaginal epithelial tissue is thin and easily damaged and stimulated by various external pathogens or chemical substances, labia are small and thin and provide little protection to the vestibule, hymen opening is small and not conducive to drainage. (2) Due to the lack of estrogen influence, vaginal pH is neutral or alkaline (6.0~8.0), lactobacillus is not the dominant bacterium, but favorable for the growth of pathogenic microorganisms, but pseudofilamentous yeast (Candida) infection is less. (3) The distance between the anus and vagina is close, the hygiene of children is poor, urine and feces are easy to contaminate the local area, and the vulva is in contact with the ground or dirty hands when playing. (4) In addition to the above anatomical, physiological and behavioral characteristics, it may also be related to obesity, systemic diseases, other vulvar skin diseases and suppressed immune function. 1.2 Susceptibility factors of vulvovaginitis during puberty: Hormonal secretion during puberty changes the vaginal flora and vaginal pH decreases to 4.0~4.5, which is suitable for the growth of acid-producing Corynebacterium, Enterobacteriaceae, Bacteroides fragilis, Pseudomonas albicans and various anaerobic bacteria; some patients have sexual activity during puberty and unprotected sexual intercourse changes the vaginal pH and dysbiosis. Therefore vulvovaginitis in adolescence is different from vulvovaginitis in young girls and to some extent similar to adult women. In addition, over-obesity, tight clothing and uncleanliness of the vulva can lead to vulvovaginitis in young girls. 2. Clinical features of pediatric vulvovaginitis 2.1 Infantile vulvovaginitis: It is mostly seen in children under 5 years of age. The most common pathogens are Staphylococcus pyogenes, Streptococcus, Escherichia coli, Corynebacterium diphtheriae, and Trichomonas, gonococcus, and pinworms. The pathogens are often transmitted indirectly through the hands, clothing, towels, and bath tubs of the child’s mother and caregiver. The clinical manifestations of vulvovaginitis in young girls are varied, such as unexplained crying, irritability, scratching of the pubic area, discomfort with urination, and even difficulty in urination. On examination, the vulva and vaginal opening are flushed and there is discharge from the underwear, sometimes with blood. There may also be no discharge and no obvious signs of infection. Since the history cannot be obtained directly from the child’s mouth and must rely on the attention and observation of the parents or guardians, its diagnosis is somewhat difficult. The consultation attitude should be cordial, pay attention to the duration, amount, viscosity and color of the discharge, fishy smell or unpleasant discharge is mostly anaerobic bacterial infection. Pay attention to the presence of other causative factors: e.g. fever, moist pubic area, friction or bacterial contamination, poor hygiene habits, etc. Find out if there is any history of diabetes, contact dermatitis, eczema, etc. in the family. 2.2 Vulvovaginitis in adolescence: usually increased vaginal discharge with color and odor changes, accompanied by vulvar itching. The clinical presentation varies slightly depending on the infecting microorganism. Gynecological examination is important for both infants and adolescents. The examination includes the labia majora and minora, vaginal opening, hymen, clitoris, urethra, anus and vagina, paying attention to keep the hymen intact. For adolescents who have not yet had sex, the secretions are obtained in the same way as for young girls, and attention is paid to protecting the integrity of the hymen. For those who are sexually active, use a speculum to observe the vagina and cervix, and also examine the pelvic cavity. The smear examination of secretions and bacteriological examination, especially the examination of pathogens that can cause sexually transmitted diseases (STD) such as gonococcus and chlamydia, and the screening of human papillomavirus (HPV) and cervical cytology are emphasized. Since adolescence is a psychologically sensitive period, medical history involving sexual life should be kept confidential. 3. Classification and treatment of pediatric vulvovaginitis According to the different pathogens, pediatric vulvovaginitis can be divided into the following 3 categories. 3.1 Non-specific vulvovaginitis: Pediatric vulvovaginitis is mainly a non-specific infection. 3.1.1 Diaper dermatitis: It is a common skin disease in infants and young children (especially those within a few months). It starts as erythema, and in severe cases blisters can occur on the erythema, or shallow ulcers can appear, which can be secondary to bacterial or pseudofilamentous yeast infection. Treatment: Improve hygiene, avoid irritation, keep dry, gently wipe locally with saline or vegetable oil, and use corticosteroids if necessary. 3.1.2 Bacterial vulvovaginitis: associated with low hormone levels and dysbiosis of the vaginal flora, including Staphylococcus, group B hemolytic streptococcus, Enterococcus, Gardnerella, Shigella, etc., extremely similar to senile vaginitis. When E. coli infection is predominant, the discharge is thin and smelly; when Staphylococcus infection is present, the discharge is yellow and purulent; when Streptococcus infection is present, the discharge is plasma and bloody; when Gardnerella infection is present, the leucorrhoea is grayish white and smells fishy. In the acute stage, the vulva is red and discharge is abundant, and pain is the main cause. In the subacute stage, itching is the main cause, and some children have ulcers on the skin or difficulty in urination. In the chronic stage, although the above symptoms are mild, there is congestion of vulva, vestibule and vaginal mucosa. Treatment: Keep the vulva clean and select the appropriate antibiotics for systemic and local application mainly according to the type of pathogen and drug sensitivity test. If treatment is ineffective for 2 weeks, vaginal examination should be considered to further search for the source of infection, except for vaginal foreign bodies, tumors or rare urethral or rectovaginal fistulas. 3.2 Atopic vulvovaginitis 3.2.1 Fungal inflammation: mainly caused by Pseudomonas albicans infection. Infections in infants and young children are mostly maternally transmitted, as the vaginal secretions are acidic within 1-2 weeks after birth and Pseudomonas is prone to growth. If there are recurrent fungal infections, diseases such as diabetes mellitus and immunocompromise should be excluded. After puberty, fungal inflammation is common, and the manifestation is similar to that of adult women, with vulvar itching, flushed skin, satellite lesions around the distribution, and discharge in the form of milk clots. The diagnosis can be confirmed by finding pseudomycorrhizae and spores in the secretions. Treatment: 2-4% sodium bicarbonate solution scrubbing vulva vaginal after local application of miconazole ointment, 2-3 times daily, for 2 weeks orally. Mycoplasma 100,000 units, 4 times a day for 3 d, or Itraconazole 200 mg, 2 times a day for 1 d. Repeat treatment for 2~3 courses. Those who are negative by 3 fungal tests after treatment are cured. For those who have fungal vaginitis during pregnancy must be cured before delivery to reduce the possibility of transmission to the newborn. All newborns born vaginally to affected mothers are given a mycoplasma suspension oral spray or prophylactic application in milk. 3.2.2 Vaginal foreign body: It is common for children aged 3-6 years to put foreign bodies such as hand paper, pencil tips, erasers and toys into the vagina out of curiosity or in an attempt to relieve vulvovaginal itching, resulting in secondary infection and increased vaginal discharge, which is purulent or bloody and has a foul odor, and even forms ulcers and granulation tissue. If bloody or purulent leucorrhea persists for a long time, the possibility of a foreign body in the vagina should be considered. Diagnosis can be assisted by probing, anal examination, ultrasound, X-ray fluoroscopy and examination of the vagina with nasal or hysteroscopy. In principle, vaginal foreign bodies should be removed under anesthesia, by anal nudge method or under nasoscope or small speculum, with special care not to damage the rectum during surgery. For foreign bodies in deeper locations, they can be removed hysteroscopically by taking the cystotomy position, selecting a hysteroscope with a caliber of 0.40-0.64 cm and placing it into the vagina, clamping the left thumb and index finger to the center of the labia majora on both sides, using saline or glucose as the medium for dilatation, and removing the foreign body with biopsy forceps [8]. Vaginal inflammation mostly subsides on its own after foreign body removal, and antibiotic ointment is applied if necessary, and systemic antibiotics are usually not needed. 3.2.3 Chemical or allergic inflammation: inflammation can be caused by stimulation of vulvar skin by urine or due to obesity, fluid exudation from vulvar skin and skin between thighs rubbing against each other, or allergy to bathing lotion, perfume, sanitary napkins, or talcum powder. Removal of allergens, local use of cortisone ointment or oral anti-allergy drugs can generally be cured. 3.3 Sexually transmitted diseases (STD) The pathogens include trichomonas, gonococcus, Chlamydia trachomatis, syphilis, herpes virus, HPV and human immunodeficiency virus (HIV). Gonorrhea and Chlamydia trachomatis vulvovaginal infections have been reported in young girls and adolescents in China. STD in adolescents is extremely dangerous and should be taken seriously by obstetricians and gynecologists. STD in infants and children is rare and is often transmitted by non-sexual routes, such as vertical transmission from mother to mother, or infection caused by incidental exposure to contaminants. 3.3.1 Trichomonas vaginalis: The appropriate vaginal pH for Trichomonas vaginalis to grow is 5.1~5.4. It does not grow below pH 5.0 or above 7.5. Before children are 12 years old, due to low estrogen levels and lack of glycogen in the vaginal epithelium, the pH in the vagina is high, which is not favorable for Trichomonas growth. After menarche, the pH in the vagina decreases and its incidence increases linearly. Clinical manifestations are the same as in adults. Treatment: external washing with acidic solution (1% lactic acid or 0.5% acetic acid) and metronidazole 50-100mg 3 times a day for 7d, or vaginal douching with metronidazole solution (small catheter inserted into the vagina) twice a day for 5-7d, repeated for 2-3 courses of treatment. Trichomonas examination was performed after each menstrual period and 3 consecutive negative tests were considered as cure. 3.3.2 Gonococcal vaginitis: It mainly occurs in adolescents and is rare in young girls. Symptoms usually appear within 1 week after contact with the infection and are characterized by flushing of the vulva, purulent discharge, swelling and pain of the vulva in some children. Since gonorrhea often causes multi-site infections, multiple sites should be sampled. In addition to the vulva and vagina, smear examination or culture of rectal and oropharyngeal secretions can help confirm the diagnosis. Even if there is no purulent discharge, bacterial smear and culture should be routinely performed for those who have suffered sexual aggression. Treatment: Ceftazidime 125mg, single intramuscular injection. Once gonococcal infection is present it means that infection to other STDs is at high risk and therefore screening for other pathogens should be done at the same time. Because of its high prevalence, the epidemiology of gonorrhea has been used as an indicator to assess the incidence of STD among adolescents. 3.3.3 Chlamydia trachomatis infection: The prevalence is 2-13% in sexually assaulted children. The most common symptoms are discharge of yellow purulent discharge from the cervical canal, migration of columnar epithelium from the cervical canal to the cervicovaginal surface, hypertrophy and ectropion of the cervix due to congestion and edema, and contact bleeding. The urethra is a common site of mycoplasma infection and may be accompanied by symptoms such as painful urination. Most of them can be clearly diagnosed based on clinical symptoms and exposure to high-risk factors of infection combined with mycoplasma culture and enzyme-linked immunosorbent assay. Treatment: for weight <45kg, erythromycin 50mg/(kg.d) orally in 4 doses for 10~14d; for weight ≥45kg, give as adult dose. 3.3.4 Genital herpes virus infection: Infected patients have fever, vulvar blisters, ulcers and pain in the acute phase, enlarged inguinal lymph nodes, and related symptoms may occur when the bladder is involved. The initial diagnosis can be made on the basis of clinical manifestations and contact history, and viral isolation tests are of great value in confirming the diagnosis. Treatment: acyclic guanosine 200mg can be given orally once every 8h for 5d. 3.3.5 HPV infection: Most of the HPV subtypes infected in children are the same as those in adults. Since the incubation period after HPV infection is several months to several years, the infection in children under 2 years old is mostly not considered as a possibility of sexual transmission. The clinical presentation is a small, single, scattered papillary lesion around the labia, clitoris and anus, which may spread to form a cauliflower-like, pinkish-red color. The diagnosis can be made on the basis of the typical clinical manifestations, and the diagnosis can be assisted by the white acetate test, and the biopsy can reveal excavated cells. Treatment: Local cautery with 75%-85% trichloroacetic acid, fluorouracil ointment, microwave, laser, etc. as appropriate, while immune function should be enhanced. 4. Pediatric internal genital inflammatory disease Pelvic inflammatory disease (PID) is highly prevalent in fertile women, and in adolescents most manifest as acute pelvic inflammatory disease or asymptomatic. The pathogens include gonococci, chlamydia or E. coli, staphylococci, streptococci, and anaerobic bacteria. The gonococcus, chlamydia and staphylococcus first invade the mucosa of the lower genital tract and travel up through the cervix, endometrium and fallopian tubes to the ovaries and pelvis, which is the main route of PID in adolescents. The diagnosis is based on history, symptoms and signs. The risk of PID in pediatric patients is much greater than in adult women, and the key to treatment is the selection of effective antibiotics based on clinical features and drug sensitivity testing. Because pediatric patients are a special group in gynecology clinics, the attitude of the medical staff must be cordial in order to gain the trust of the children, especially for those who have been sexually abused, physical and psychological harm should be avoided, and the examination must be gentle, and the examination of secretions should be emphasized as in adult women, but attention should be paid to non-invasive. The level of diagnosis and treatment of pediatric genital tract infections, especially vulvovaginitis, has improved greatly in recent years, with systemic treatment being the mainstay.