Which condition is characterized by deposits of immunoglobulins in small blood vessels?

Henoch-Schönlein purpura (HSP) is a small-vessel vasculitis characterized by deposits of immunoglobulins, particularly IgA, in the small blood vessels. HSP typically presents with a classic tetrad of symptoms: skin rash (purpura), joint pain, abdominal pain, and renal involvement, primarily seen as IgA nephropathy. The immunoglobulin deposits can trigger inflammation and damage the vessel walls, leading to the various manifestations associated with this condition.

Understanding the pathophysiology of HSP helps clarify why it is specifically recognized for these immunoglobulin deposits. The presence of the IgA complexes in the skin, joints, intestines, and kidneys is integral to the development of the associated symptoms. This triggered immune response results in small-vessel vasculitis, which is the hallmark of Henoch-Schönlein purpura.