What is Allergic Purpura?

Allergic purpura, also known as Henoch-Schönlein purpura, is a common vasculitic disease. Its main manifestations include skin purpura, joint pain, abdominal pain, and kidney damage. This disease most commonly affects children between the ages of 2 and 6. Its pathogenesis is associated with abnormal immune responses and may be triggered by infections, foods, medications, or other factors.

The disease can be classified into different types according to the affected areas: cutaneous, abdominal, arthritic, renal, and mixed types of allergic purpura. Typically, the rash first appears on both lower limbs and can also involve the buttocks and upper limbs. Joint pain mainly affects the knees, ankles, wrists, and elbows, manifesting as joint swelling, pain, and limited movement, but generally does not cause permanent joint damage.

In addition, abdominal pain often occurs, commonly accompanied by nausea and vomiting. In severe cases, gastrointestinal bleeding may develop. Approximately one-third of patients will experience kidney involvement during the course of the disease. Some male patients may also develop inflammation of the scrotum and testicles. In a few patients, the nervous system may be affected, leading to symptoms such as headache, seizures, and epilepsy.