**3.3 The disease**

In the pediatric population, CT is associated with several clinical conditions, these include conjunctivitis, nasopharyngitis, and pneumonia in young infants; and in the case of children and adolescents: genital tract infection, lymphogranuloma venereum, and trachoma.

Neonatal conjunctivitis is vertically transmitted, the neonate usually shows ocular congestion, edema, and discharge; these could last 1 to 2 weeks after birth. Pneumonia can be seen in young infants, normally occurs between 2 and 19 weeks after birth; could be afebrile and it is associated with hyperinflation of the lungs, nasal stuffiness, and otitis media; its presence could indicate immunosuppression.

Clinical manifestations in children and adolescents with genitourinary CT include vaginitis in prepubertal females and the post-pubertal females can present the Fitz-Hugh-Curtis syndrome (urethritis, cervicitis, endometritis, salpingitis, proctitis, and perihepatitis); also described for gonorrhea infections. In males, the most frequent manifestations are urethritis, epididymitis, and proctitis; also, Reiter syndrome can be seen (reactive arthritis, urethritis, and bilateral conjunctivitis) [20]. Lymphogranuloma venereum is another clinical manifestation of CT infection in adolescents; this is an invasion of the lymphatic nodes that generates an ulcerative lesion in the genital area plus inguinal or femoral or both lymphadenopathies, typically unilateral.

#### *Sexually Transmitted Infections in Pediatrics DOI: http://dx.doi.org/10.5772/intechopen.101674*

Young age is a strong predictor of CT infection, particularly prevalent in individuals younger than 25 years. CT infection is normally asymptomatic in both men and women (routine screening is essential for the detection); this situation increases the transmission between partners (rates are greater than 50%); also, it is important to highlight that transmission is more efficient from men to women. The incubation period ranges from 7 to 21 days after exposure. In the case of neonates, at least 60–70% acquire conjunctivitis when exposed to CT during passage through the birth canal [18]. The most common clinical presentations are described in **Figure 1**.

CT extra-genitourinary manifestations include rectal and oropharyngeal infections. Rectal infection is presented as proctitis; this can be acquired by sexual anal intercourse and due to autoinoculation in women. In the case of the oropharynx, the infection is usually asymptomatic, sometimes it can be presented as pharyngitis or cervical lymphadenopathy.

Finally, trachoma is a form of chronic keratoconjunctivitis, follicular with neovascularization of the cornea; blindness occurs in 1–15% of the affected population.

#### **3.4 Diagnosis**

Untreated CT infections can lead to complications like infertility (20%), lifethreatening tubal pregnancy (9%), and debilitating chronic pain (18%). Currently, the best method for CT infection detection is the Nucleic acid amplification tests (NAATs). NAATs offer greatly expanded sensitivities of detection, usually well above 90%, while maintaining very high specificity, usually ≥99%. Currently, NAATs are the approved tests by international regulatory organisms for the detection of genital tract infections caused by CT in men and women with and without symptoms. Acceptable samples for NAATs are vaginal swabs in women and first catch urine from men. The performance of NAATs for overall sensitivity, specificity, and ease of specimen transport is better than that of any of the other tests available for the diagnosis of chlamydial infections NAATs are cost-effective in preventing sequelae due to CT [21].

#### **Figure 1.** *Chlamydia trachomatis clinical manifestations and evolution.*

#### *3.4.1 Screening tests in the adolescent population*

#### *3.4.1.1 Genitourinary CT detection*

As mentioned above, for female screening, samples from vaginal swabs are the preferred ones; these areas are sensitive as cervical swabs with similar specificity; for clinical and research settings it is also important to know that self-collected vaginal swabs are equivalent in sensitivity and specificity to those collected by health care personnel. Cervical samples could be done as part of pelvic examinations but not as routine tests; in general, cervical samples should be avoided; vaginal swabs should be preferred in all cases [21].

Currently, there are no specific recommendations for CT screening in heterosexual men. Recommendations are recommended only in specific settings such as sexually active heterosexual men in clinical settings with a high prevalence of C. trachomatis (i.e., sexually transmitted diseases clinics, adolescent clinics, detention and prisons, persons entering the armed forces. Etc).

#### **3.5 Treatment**

Treatment can be classified depending on the type of clinical manifestations that are frequently associated with the group of age. In infants with conjunctivitis or pneumonia, the treatment is oral erythromycin base or ethylsuccinate (50 mg/kg/ day in 4 divided doses daily for 14 days) or with azithromycin (20 mg/kg, single daily dose for 3 days). When CT infection is detected in an infant, the mother and her sexual partner(s) must receive treatment. In the neonates, the presence of CT infection must alert the physician for also detecting Ng. Any infant younger than 6 weeks and treated with oral erythromycin or azithromycin must be monitored for any signs or symptoms of hypertrophic pyloric stenosis [20].

In adolescents with uncomplicated anogenital CT, the recommendation is doxycycline 100 mg, twice daily for 7 days; or azithromycin 1 g oral in a single dose. In affected children who weigh less than 45 kg the recommendation is oral erythromycin base or ethylsuccinate 50 mg/kg/day divided into 4 doses, daily for 14 days. For children younger than 8 years but weighing 45 kg or more, the recommendation is azithromycin 1 g orally in a single dose. In the case of 8 years and older children, the recommendation is azithromycin 1 g orally in a single dose; or doxycycline 100 mg orally 2 times a day for 7 days. Test of cure is not recommended; repeating the test 3 or 4 weeks after therapy to detect treatment failures can be done only if: adherence is in question, symptoms persist, or reinfection is suspected [17, 19, 20].

The treatment for lymphogranuloma venereum is with doxycycline 100 mg, orally twice daily for 21 days. Trachoma can be treated with oral azithromycin, a single dose of 20 mg/kg (maximum dose of 1 g) is recommended [20].

#### **4. Genital herpes**

#### **4.1 Epidemiology**

Genital herpes caused by HSV-2 and HSV-1 has been considered prevalent worldwide. The estimated global prevalence of these 2 pathogens is:


#### *Sexually Transmitted Infections in Pediatrics DOI: http://dx.doi.org/10.5772/intechopen.101674*

A comparison between the most important epidemiological features is presented in **Figure 2**.

In several developed settings (e.g., the USA, Western Europe, Australia, and New Zealand) there is evidence that the proportion of first-episode genital herpes that is due to HSV-1 has increased, particularly among young people [25, 26]. Characteristics related to the first episode, latency site, viral shedding, and subsequent recurrence are presented in **Figure 3**.

Complications in HSV-2 are rare besides genital herpes; in HSV-1, the most common identified complications are sporadic encephalitis and ophthalmic disease in children and adults. HSV-2 rarely causes neonatal herpes, but these types of infections have a much more severe neurologic outcome. HSV-1 in the neonate, even rare can cause a devastating illness with high morbidity and mortality; when mothers shed genital HSV at delivery, HSV-1 may be more likely to be transmitted to the neonate [26].
