**Core Concept**
Henoch-Schonlein purpura (HSP) is a form of vasculitis that affects small vessels, characterized by IgA deposition and inflammation. It typically presents with palpable purpura, abdominal pain, and sometimes renal involvement.

**Why the Correct Answer is Right**
The presence of non-blanching purpura and recurrent abdominal pain, along with IgA deposition, is consistent with Henoch-Schonlein purpura. The deposition of IgA immune complexes in the skin and other tissues leads to inflammation and damage to small vessels. The renal involvement can range from mild hematuria to severe kidney failure.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the presence of IgA deposition, which is a hallmark of Henoch-Schonlein purpura. Other conditions, such as idiopathic thrombocytopenia purpura (ITP), can also present with purpura but lack IgA deposition.

**Option B:** This option is incorrect because it does not account for the specific symptoms of Henoch-Schonlein purpura, such as abdominal pain and renal involvement. Other forms of vasculitis, such as granulomatosis with polyangiitis (GPA), can present with similar symptoms but have different underlying pathologies.

**Option C:** This option is incorrect because it does not specify the age group and presentation of Henoch-Schonlein purpura. Kawasaki disease is a condition that primarily affects children under the age of 5 and presents with fever, rash, and lymphadenopathy.

**Option D:** This option is incorrect because it does not account for the specific symptoms of Henoch-Schonlein purpura, such as abdominal pain and renal involvement. Other forms of vasculitis, such as polyarteritis nodosa (PAN), can present with similar symptoms but have different underlying pathologies.

**Clinical Pearl / High-Yield Fact**
Henoch-Schonlein purpura is a classic example of a vasculitis that affects small vessels and is characterized by IgA deposition. Remember the "tetrad" of symptoms: palpable purpura, abdominal pain, renal involvement, and arthritis.

**Correct Answer:** C.