**Core Concept**
IgA deposits in the dermis are a hallmark of immune complex-mediated vasculitis, particularly in small vessel inflammation. In Henoch-Schönlein purpura (HSP), IgA immune complexes deposit in blood vessel walls, leading to purpuric rash, joint pain, abdominal pain, and renal involvement.

**Why the Correct Answer is Right**
In Henoch-Schönlein purpura, IgA immune complexes form in response to infection (often viral or bacterial), deposit in the walls of small vessels, and trigger complement activation and inflammation. Skin biopsy shows IgA deposits primarily in the dermal papillae, with perivascular or subepidermal deposition. This pattern is pathognomonic for HSP and distinguishes it from other vasculitides. The presence of IgA deposits is a key diagnostic feature.

**Why Each Wrong Option is Incorrect**
Option B: Giant cell arteritis primarily affects large arteries (e.g., temporal artery), presents with headache and jaw claudication, and shows no IgA deposits; it is a large vessel vasculitis, not associated with skin IgA deposits.
Option C: Microscopic polyangitis involves immune complex deposition, but predominantly with **IgG and C3**, not IgA, and shows end-organ damage like glomerulonephritis.
Option D: Wegener's granulomatosis (now GPA) shows **IgG and C3** deposits in small vessels, with granulomatous inflammation and necrotizing vasculitis, not IgA-specific deposition.

**Clinical Pearl / High-Yield Fact**
Remember: **IgA deposits = Henoch-Schönlein purpura**. This is a classic association that appears frequently in dermatology and rheumatology exams. Always consider HSP in children with purpuric rash and abdominal pain.

✓ Correct Answer: A. Henoch Schouleiln puspura