**Question:** Which of the following is/are not the features of Henoch-Schonlein purpura (HSP) -

A. Purpura (intracapillary immune complex deposition)
B. Nephritis (glomerular immune complex deposition)
C. Arthritis (joint pain and swelling)
D. Vasculitis (inflammation of blood vessels)

**Correct Answer:**

Henoch-Schonlein purpura (HSP) is a small vessel vasculitis characterized by immune complex deposition in small blood vessels, leading to characteristic clinical features. The correct answer is:

**Option C: Arthritis**

Arthritis is not a specific feature of Henoch-Schonlein purpura. Although joint pain and swelling can be present in some patients, it is not a universal symptom in HSP. The condition primarily involves the skin, gastrointestinal tract, kidneys, and occasionally the joints.

**Option D: Nephritis**

Nephritis, characterized by glomerular immune complex deposition, is a significant feature of Henoch-Schonlein purpura. It is present in approximately 50-75% of cases and can lead to renal dysfunction or even kidney failure if not properly managed.

**Option B: Vasculitis**

Vasculitis refers to inflammation of the blood vessels, which is a primary feature of Henoch-Schonlein purpura. Vasculitis in HSP is typically a small vessel vasculitis involving the dermal and subcutaneous tissues, leading to the characteristic purpuric rash.

**Option A: Purpura**

Purpura is the presence of petechiae or purpura (small hemorrhages) on the skin, and it is a specific and characteristic feature of Henoch-Schonlein purpura. It is a result of intravascular immune complex deposition in the skin, which causes microvascular damage and bleeding.

In summary, Henoch-Schonlein purpura is characterized by vasculitis, purpura, nephritis, and joint involvement. While arthritis can be present in some cases, it is not a defining feature of the condition. Nephritis and vasculitis are the key features that distinguish HSP from other conditions with similar symptoms like Henoch-Schönlein purpura and IgA Nephropathy.