Children often present to emergency departments (EDs) with uncontrollable nose bleeding. Although usually due to benign etiologies, epistaxis may be the presenting symptom of an inherited bleeding disorder. Whereas most bleeding disorders are detected through standard hematologic assessments, diagnosing rare platelet function disorders may be challenging. Here we present two case reports and review diagnostic and management challenges of platelet function disorders with a focus on Glanzmann's thrombasthenia (GT). Patient 1 was a 4-year-old boy with uncontrolled epistaxis. His medical history included frequent and easy bruising. Previous laboratory evaluation revealed only mild microcytic anemia. An otolaryngologist stopped the bleeding, and referral to a pediatric hematologist led to the definitive diagnosis of GT. Patient 2 was a 2.5-year-old girl with severe epistaxis and a history of milder recurrent epistaxis. She had a bruise on her abdomen with a palpable hematoma and many scattered petechiae. Previous assessments revealed no demonstrable hemostatic anomalies. Platelet aggregation studies were performed following referral to a pediatric hematologist, leading to the diagnosis of GT. As evidenced by these cases, the ED physician may often be the first to evaluate severe or recurrent epistaxis and should recognize indications for coagulation testing and hematology consultation/referral for advanced hematologic assessments.