Henoch-Schönlein Purpura (HSP): This condition is a form of vasculitis that affects blood vessels and is common in children and adolescents. It often presents with purpura (which could be mistaken for small hematomas), particularly on the lower extremities, but can also appear on the buttocks and elbows. The "petite eye" description could be indicative of periorbital edema, which is sometimes seen in HSP. The absence of trauma history and the presence of these symptoms make HSP a plausible diagnosis.

Allergic Purpura: This could be due to an allergic reaction causing blood vessels to leak, leading to purpura or small hematomas. The lack of trauma and the presence of these skin findings could suggest an allergic cause.
Infectious Diseases (e.g., Meningococcemia): Certain infections can cause petechiae or purpura, especially if they affect the blood vessels or lead to coagulopathy. Meningococcemia, for example, can cause a rash that might initially appear as small hematomas or petechiae.
Idiopathic Thrombocytopenic Purpura (ITP): This condition involves low platelet counts, which can lead to easy bruising and the formation of small hematomas. The absence of a clear trauma history could point towards a condition like ITP.

Child Abuse: Although the patient denies a history of trauma, it's crucial to consider non-accidental injury, especially if the pattern of injuries is suspicious or if there are inconsistencies in the history provided.
Malignancy (e.g., Leukemia): Certain types of cancer, such as leukemia, can cause easy bruising or bleeding due to bone marrow suppression or coagulopathy. It's essential to rule out malignancy, even though it might be less common.
Bleeding Disorders (e.g., Hemophilia): Conditions that affect coagulation can lead to easy bruising or hematoma formation without significant trauma.

Ehlers-Danlos Syndrome: A group of disorders that affect connective tissues supporting the skin, bones, blood vessels, and many other organs and tissues. Some types can lead to easy bruising or poor wound healing.
Vasculitis (other forms): Besides HSP, other forms of vasculitis (like granulomatosis with polyangiitis or microscopic polyangiitis) could potentially cause similar symptoms, though they are less common in adolescents.
Scurvy: Vitamin C deficiency can lead to poor collagen synthesis, resulting in bleeding gums, joint pain, and easy bruising. However, this would be rare in a well-nourished adolescent without a specific dietary deficiency.