Trichotemnomania (TT) is characterized as the cutting or shaving of hair, which is an obsessive– compulsive habit. TT takes its name from a fusion of Greek words: thrix (hair), temnein (to cut), and mania (madness). TT is a very rare disease with only five case studies reported in the literature and to the best of our knowledge; no data are available on adolescents. This study focuses on three cases of adolescents with TT. All patients have been evaluated by a dermatologist and two child and adolescent psychiatrists. Dermatological examinations included medical history, physical examination, dermoscopy assessment, and laboratory investigations. Detailed psychiatric assessments consisted of socio-demographic data, clinical history, semi-structured interviews, and psychometric tests. Three cases with TT were both diagnosed with obsessive–compulsive disorder. Two of them diagnosed comorbid social anxiety disorder (in cases 1 and 2), and one case diagnosed with comorbid general anxiety disorder (in case 3) and agoraphobia (in case 3). Cases 1 and 2 were prescribed 50 mg/day of sertraline; however, case 3 refused the treatment. In conclusion, TT may be confused with trichotillomania or other disorders presented with alopecia. Differential diagnoses may be due to histopathological changes or dermoscopic assessment. Dermatologists should consider TT when a supposed alopecia areata looks somewhat unusual and should refer these patients for psychiatric evaluation.