Endometriosis in Adolescents: A Closer Look at the Pain Characteristics and Atypical Symptoms: A Prospective Cohort Study

Background/Objectives: Endometriosis affects up to 10% of women of reproductive age and about 47% of adolescents with pelvic pain. Symptoms include dysmenorrhea, dyspareunia, and chronic pelvic pain (CPP). Adolescents often present atypical symptoms that can make endometriosis more difficult to diagnose. This study aimed to compare characteristics of pain, atypical symptoms, and the effects of hormonal treatments between adolescents and adults with endometriosis. Methods: A total of 238 women with endometriosis were included: 92 aged 12–18 (group A) and 146 over 18 (group B). Data on menarches, cycle length, comorbidities, dysmenorrhea, dyspareunia, CPP, analgesic use, pain characteristics, atypical symptoms, and endometrioma size were recorded. The efficacy, compliance, and side effects of hormonal treatments were also assessed. Quality of life (QoL) was measured using the SF-12 questionnaire at baseline and after six months of therapy. Results: Adolescents had earlier menarche (p < 0.001), longer menstrual periods (p < 0.001), and higher analgesic use (p = 0.001) compared to adults. Dysmenorrhea was more frequent (p = 0.01), lasted longer (p < 0.001), and was associated with higher pain scores (p < 0.001) in adolescents. CPP was more common in adolescents (p < 0.001), often described as “confined” (p = 0.04) and “oppressive” (p = 0.038), while adults reported it as “widespread” (p = 0.007). Headaches (p < 0.001) and nausea (p = 0.001) were also more frequent in adolescents. Both groups showed significant improvement in QoL with hormonal treatment (p < 0.001) and reported minimal side effects. Conclusions: Adolescents with endometriosis often present with earlier menarche, longer menstrual periods, more severe dysmenorrhea, and atypical symptoms. Hormonal contraceptives and dienogest are effective and safe treatments that improve pain and QoL.