This tool helps assess if someone meets the European League Against Rheumatism (EULAR), Pediatric Rheumatology International Trials Organization (PRINTO), and Pediatric Rheumatology European Society (PRES) criteria for Henoch-Schönlein purpura (HSP), a condition characterized by a small-vessel vasculitis. To determine this, you consider specific clinical signs and symptoms:

Inputs entail selecting from these criteria:

- Purpura or petechiae predominantly on the lower limbs, which is not linked to thrombocytopenia
- Sudden onset of severe abdominal pain, possibly with intussusception or gastrointestinal bleeding
- Biopsy indicating leucocytoclastic vasculitis or glomerulonephritis with IgA dominance
- Sudden onset arthritis, where there is joint swelling or pain limiting motion
- Sudden onset arthralgia, where there is joint pain but no swelling or motion restriction
- Proteinuria surpassing 0.3 g/24 hours or a specified albumin/creatinine ratio in a morning urine spot test
- Hematuria or red blood cell casts identified through urinary analysis 

The computation follows this logic:

- Confirm if purpura or petechiae with lower limb predominance is present.
- Check for at least one additional symptom or finding from the other criteria indications.

To meet the criteria for HSP, the individual must have purpura or petechiae primarily on the lower limbs and at least one other clinical sign from the list. If both are present, it concludes with "Meets criteria for Henoch-Schönlein purpura." Otherwise, it suggests "Criteria not met."

This evaluation is crucial for healthcare professionals to decide on further investigations and make management decisions for patients suspected of having HSP.

The EULAR/PRINTO/PRES criteria for Henoch-Schönlein purpura (HSP) is a diagnostic tool developed by the European League Against Rheumatism (EULAR), the Paediatric Rheumatology International Trials Organisation (PRINTO), and the Paediatric Rheumatology European Society (PRES). This calculator is specifically designed for the pediatric population, as HSP is primarily a disease of childhood.

The EULAR/PRINTO/PRES criteria for HSP is used to establish a diagnosis of HSP, a type of vasculitis that affects small blood vessels, typically presenting with palpable purpura, arthritis or arthralgia, abdominal pain, and renal involvement. The criteria include mandatory and additional criteria, and a diagnosis of HSP is made when the mandatory criterion (palpable purpura or petechiae, not related to thrombocytopenia) is present along with at least one of the additional criteria.

The clinical utility of this calculator is to aid in the diagnosis of HSP, which can help guide appropriate treatment and management strategies. It can also help differentiate HSP from other conditions that may present with similar symptoms.

There are no specific exclusion criteria for the use of the EULAR/

EULAR/PRINTO/PRES criteria for Henoch-Schönlein purpura

EULAR / PRINTO / PRES criteria for Henoch-Schönlein purpura, childhood polyarteritis nodosa, childhood Wegener granulomatosis and childhood Takayasu arteritis: Ankara 2008. Part II: Final classification criteria.