Final answer:
The symptoms suggest Henoch-Schönlein purpura (HSP), a common vasculitis in children, which typically resolves on its own with symptom management as the primary treatment. Severe cases might require corticosteroids or other immunosuppressants.
Step-by-step explanation:
The symptoms described - purpura, abdominal pain, and arthritis - in a child less than 10 years old are suggestive of Henoch-Schönlein purpura (HSP). HSP is characterized by these specific symptoms due to inflammation of small blood vessels, and it's among the most common vasculitis disorders in children.
Treatment for HSP primarily involves symptom management, since the condition often resolves on its own. Severe cases may require medications like corticosteroids to reduce inflammation or other immunosuppressive drugs. Ensuring proper hydration and pain relief with over-the-counter analgesics like acetaminophen or ibuprofen is also essential. It's critical for the child to have rest and to monitor for symptom progression, as some may develop kidney involvement, which is a more serious complication of the disease.