**Question:** True about Henoch-Schonlein purpura is following except:

A. It is a hereditary disease.
B. It is a cutaneous manifestation of systemic vasculitis.
C. It is caused by a viral infection.
D. Its symptoms resolve completely within a week.

**Correct Answer:** C. It is caused by a viral infection.

**Core Concept:** Henoch-Schonlein purpura (HSP) is a systemic small-vessel vasculitis, primarily affecting children, characterized by purpura (non-thrombocytopenic), abdominal pain, joint pain, and renal involvement. It is typically triggered by a viral infection, typically preceding or coinciding with the onset of symptoms. The pathophysiology involves immune complex deposition in blood vessels, causing inflammation, pain, and organ dysfunction.

**Why the Correct Answer is Right:** Henoch-Schonlein purpura (HSP) is primarily a disease of childhood, with an estimated incidence of 2-15 cases per 100,000 children per year. The condition is characterized by small vessel vasculitis involving the skin, gastrointestinal tract, joints, and kidneys. The clinical presentation includes non-thrombocytopenic purpura, abdominal pain, joint pain, and renal involvement. The disease is typically triggered by a viral infection, usually preceding or coinciding with the onset of symptoms. The immune response to the infection leads to the production of immune complexes, which deposit in small blood vessels, causing inflammation and damage to the affected organs.

**Why Each Wrong Option is Incorrect:**

A. Henoch-Schonlein purpura is not a hereditary disease. It primarily affects children and is triggered by a viral infection, not caused by genetic factors.

B. Although HSP can cause skin involvement, it is not limited to the skin. The disease involves multiple organ systems like the gastrointestinal tract, joints, and kidneys.

C. Viral infections are not the primary cause of Henoch-Schonlein purpura. The disease is triggered by a viral infection, leading to immune complex deposition in small blood vessels and inflammation. A viral infection itself does not cause the disease.

D. HSP typically resolves within 2-3 weeks, not within a day. Symptoms usually last for several days to a few weeks and can lead to complications, including renal involvement and hypertension.

**Clinical Pearls:**

1. Henoch-Schonlein purpura is a clinical diagnosis based on the patient's history and physical examination findings. Confirmatory tests like renal biopsies are usually needed to establish the diagnosis.
2. The disease should be differentiated from other causes of petechiae and purpura, such as thrombocytopenia, hemolytic anemia, or immune thrombocytopenic purpura (ITP).
3. Treatment primarily focuses on supportive care, managing complications, and treating symptoms like pain and hypertension. Antiviral therapy is not typically used, as viral infections are not the primary cause of HSP.
4. Prognosis is generally good, with the majority of patients experiencing