- Hemophilia is characterized by spontaneous bleeding into joints and muscles, often without preceding trauma, due to deficiency of clotting factors VIII (Hemophilia A) or IX (Hemophilia B).
- This leads to a defective intrinsic coagulation pathway, causing prolonged bleeding episodes.
- Unlike other disorders, hemophilia bleeding tends to be deep and internal rather than mucocutaneous.
- Spontaneous hemarthroses and muscle hematomas are hallmark features.
- Von Willebrand disease primarily causes mucosal bleeding, Vitamin K deficiency affects multiple factors but rarely causes spontaneous severe bleeding, and Idiopathic thrombocytopenic purpura involves low platelet counts with petechiae rather than deep spontaneous bleeds.

Reference: Davidson’s Principles and Practice of Medicine, 24th Edition, Chapter: Disorders of Haemostasis and Thrombosis, Page 883.