Henoch-Schonlein purpura exhibits four primary symptoms, including rash, sore joints, gastrointestinal maladies and kidney problems, according to Mayo Clinic. Not all who contract the disease exhibit all four symptoms.
The rash from Henoch-Schonlein purpura shows up as reddish-purple spots usually appearing on the buttocks, legs and feet, but the rash may appear in other areas, explains Mayo Clinic. The rash is the most distinctive of the symptoms. It is best to see a doctor as soon as the rash appears.
Henoch-Schonlein purpura also causes joints to become painful and swollen, notes Mayo Clinic. Commonly, it impacts the knees and ankles. These symptoms do not leave lasting effects after the disease passes. People with Henoch-Schonlein purpura may experience gastrointestinal problems, such as vomiting, nausea, general abdominal pain and bloody stools. The disease may affect the kidneys, signaled by the presence of protein or blood in the urine.
Doctors believe Henoch-Schonlein purpura is due to the immune system acting improperly. This causes small blood vessels to become inflamed, and bleeding within the skin may occur. About half of the people who contract the disease develop it after having a cold or other upper-respiratory infection. Other leading factors that precede the condition include chickenpox, strep throat, or the effects of medication, food, or insect bites.