**Core Concept**
The patient's presentation of ecchymosis and petechiae suggests a bleeding disorder, likely related to platelet dysfunction or a low platelet count. The absence of hepatosplenomegaly makes conditions like idiopathic thrombocytopenic purpura (ITP) more likely.

**Why the Correct Answer is Right**
Bleeding into the joints is not a characteristic feature of ITP, which primarily presents with mucocutaneous bleeding (ecchymosis, petechiae). Conditions like hemophilia A and B, which cause bleeding into joints, are not consistent with the absence of hepatosplenomegaly. The correct answer, B, is meant to distract from the actual diagnosis.

**Why Each Wrong Option is Incorrect**
**Option A:** Increased megakaryocytes in the bone marrow are consistent with ITP, where the bone marrow attempts to compensate for the low platelet count by increasing megakaryocyte production.

**Option C:** Decreased platelet count in the blood is a hallmark of ITP, which is characterized by immune-mediated platelet destruction.

**Option D:** ITP can resolve spontaneously, and about 80% of patients with ITP have a spontaneous resolution within 6-12 months, although relapses can occur.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that ITP often presents with mucocutaneous bleeding (ecchymosis, petechiae) without significant bleeding into joints. This clinical correlation can help differentiate ITP from other bleeding disorders.

**✓ Correct Answer: B. Bleeding into the joints**