What Is Henoch-Schönlein Purpura?

The primary manifestation of Henoch–Schönlein purpura (HSP) is cutaneous purpura. In cases involving skin involvement alone, patients may experience no subjective symptoms. However, when joints, the gastrointestinal tract, or kidneys are affected, distinct clinical symptoms may arise. So, what exactly is Henoch–Schönlein purpura?

Symptoms of Henoch–Schönlein Purpura

Henoch–Schönlein purpura is an allergic small-vessel vasculitis affecting capillaries and small arteries in the skin or other organs. It is the most common form of cutaneous vasculitis in children. Skin lesions predominantly occur on the extensor surfaces of the lower legs and present as palpable, non-blanching purpuric lesions. They typically appear symmetrically, with more severe involvement over pressure points. In severe cases, purpuric lesions may coalesce into large ecchymotic patches or even progress to vesicle formation. Lesions usually develop acutely and resolve spontaneously within approximately one week, often leaving residual hyperpigmentation. The disease course varies; some cases recur, while others—particularly severe ones—may present with abdominal pain, hematochezia, or other systemic manifestations.

Classic HSP predominantly affects children and adolescents, with a higher incidence in males than females. Lesions most commonly involve the lower extremities—especially the extensor surfaces of the calves—but in severe cases may extend to the upper limbs and trunk. The characteristic rash initially appears as discrete, pinpoint, bright-red petechiae, approximately the size of soybeans, which may coalesce into larger purpuric patches. Disease duration varies widely—ranging from weeks to months or even years—and recurrence is common.

Cutaneous manifestations are present in virtually all cases of HSP. When only the skin is involved, the condition is termed “simple” or “cutaneous-only” HSP. Additionally, 50%–75% of patients develop arthralgia or arthritis—termed “arthritic-type” HSP—with large joints most frequently affected. Joint symptoms are typically transient and self-limiting.