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Background: Palpable purpura (PP) is defined by the presence of elevated hemorrhagic plaques or papules, which can be triggered by various underlying conditions.
Objectives: To evaluate the clinical conditions leading to PP and identify the parameters that predict the differential diagnosis.
Methods: This retrospective observational study includes patients who were diagnosed with PP in a tertiary rheumatology outpatient clinic between January 2017 and July 2023. Patients with PP whose pathology results were compatible with leukocytoclastic vasculitis were classified according to the revised International Chapel Hill Consensus Conference. Patients’ files were assessed retrospectively for demographic, clinical, and laboratory data.
Results: There were 126 patients (66 Male/60 Female) with a median age of 50.5 (interquarter range 34.8). The mean follow-up period was 40.8±22.9 months. The leading diagnoses in patients with PP were Henoch-Schönlein purpura (HSP) in 83 (65.8%) patients, immune complex vasculitis (IgG/M) in 23 patients (18.2%), cutaneous leukocytoclastic vasculitis in 9 (7.1%) and hypocomplementemic urticarial vasculitis in 8 (6.3%) patients. Cutaneous polyarteritis nodosa (PAN), ANCA-associated vasculitis, and infection-related vasculitis were diagnosed in one patient each. The most common presumed etiological factors were infectious diseases in 47 (36.7%) patients and drug intake in 41 (32%) patients within the entire patient group. Abdominal pain, gastrointestinal bleeding, and arthritis were also frequently observed as part of the initial presentation in patients with HSP. In patients with HSP, the onset of complaints was more seasonal, with a frequent occurrence during the autumn season. BVAS scores and 24-hour urine protein levels were higher in patients with HSP vasculitis compared to those with other diagnoses of PP. In multivariate analyses, patients with only skin involvement, positive rheumatoid factor (RF), positive anti-nuclear antibody (ANA), elevated albumin levels, and decreased ferritin levels were identified as more predictive indicators for immune complex vasculitis and various types of leukocytoclastic vasculitis, excluding HSP (Table 1). Over the two-year follow-up of patients with PP, five were diagnosed with Familial Mediterranean Fever, three with primary Sjögren’s syndrome, two with multiple myeloma, and one each with rheumatoid arthritis, cutaneous polyarteritis nodosa, Behçet’s, and Crohn’s disease.
Conclusion: The presentation of patients with PP was predominantly associated with HSP. Although biopsy serves as a guide for classification at the time of diagnosis in patients presenting with PP, accompanying symptoms, laboratory tests, systemic involvements, and other rheumatological diseases introduce during the follow-up are important markers in guiding diagnosis and management.
Univariate and multivariate logistic regression analysis to compare other types of vasculitis with Henoch-Schönlein purpura
| Parameters | Univariate analysis | Multivariate analysis | ||||
|---|---|---|---|---|---|---|
| OR | 95% CI | p value | OR | 95% CI | p value | |
| Sex | 2.162 | 1.032-4.526 | 0.041 | |||
| Initial symptom-purpura | 2.162 | 1.032-4.526 | 0.041 | |||
| Seasonal pattern (Autumn) | 0.309 | 0.123-0.776 | 0.012 | |||
| Etiological Factor (idiopathic) | 2.501 | 1.093-5.723 | 0.030 | |||
| GI involvement | 0.225 | 0.063-0.805 | 0.022 | |||
| Renal involvement | 0.198 | 0.056-0.704 | 0.012 | |||
| Joint Involvement | 0.345 | 0.143-0.833 | 0.018 | |||
| Only skin involvement | 5.217 | 2.381-11.431 | <0.001 | 5.525 | 2.041-14.959 | 0.001 |
| BVAS score, at diagnosis | 0.872 | 0.789-0.967 | 0.009 | |||
| Low C4 | 0.969 | 0.942-0.997 | 0.029 | |||
| Positive RF | 26.529 | 3.295-213.587 | 0.002 | 65.813 | 4.515-959.223 | 0.002 |
| Positive ANA | 10.125 | 2.082-49.239 | 0.004 | 124.322 | 4.381-3527.821 | 0.005 |
| Proteinuria ≥1 g | 0.095 | 0.012-0.744 | 0.025 | |||
| Albumin | 3.645 | 1.625-8.176 | 0.002 | 9.814 | 2.455-39.287 | 0.001 |
| Ferritin | 0.993 | 0.987-0.999 | 0.021 | 0.990 | 0.981-0.999 | 0.022 |
C4: Complement 4, RF: rheumatoid factor, ANA: antinuclear antibody, BVAS: Birmingham Vasculitis Activity Score, GI: Gastrointestinal, OR: Odds Ratio CI: Confidence interval
REFERENCES: NIL.
Acknowledgements: NIL.
Disclosure of Interests: None declared.