Table.

DADA2 with vasculitic phenotype mimickers in the rheumatological setting.

MimickersSimilar FeaturesDifferent Features
Polyarteritis nodosa

  • Histologic findings

  • Cutaneous and systemic involvement are often indistinguishable

  • Older age at onset

  • HBV/HCV-related in many cases

  • No spleen enlargement

  • No cytopenias, usually thrombocytosis

  • “Rosary sign” on imaging

  • Usually responsive to steroids and common immunosuppressants

  • Usually monophasic course

Behçet disease

  • Oral and gastrointestinal ulcerations

  • Brainstem involvement

  • Subcutaneous nodules

  • Testicular involvement

  • Relapsing/remitting or chronic course

  • Good response to TNF blockade

  • Genital ulcerations

  • Panuveitis

  • Pathergy

  • Venous involvement

Systemic lupus erythematosus

  • Spleen enlargement, lymph node hyperplasia

  • Fever

  • Cytopenias

  • Oral ulcerations

  • Early-onset stroke

  • Nephrogenic hypertension

  • Raynaud phenomenon

  • Livedo reticularis

  • Digital and mesenteric vasculitis

  • Arthralgias

  • Optic neuritis

  • Relapsing/remitting or chronic course

  • Autoantibody positivity

  • Nephritic and nephrotic syndrome

  • Photosensitive rash

  • Psychosis

  • Hypergammaglobulinemia

  • Cytopenias are normally due to autoimmunity

Antiphospholipid syndrome

  • Livedo reticularis

  • Skin ulcerations and cutaneous necrosis

  • Digital ischemia

  • Thrombocytopenia

  • Early-onset stroke

  • Nephrogenic hypertension

  • High titers and persistent positivity of antiphospholipid antibodies

  • Obstetric complications

  • Thrombosis without significant inflammation

  • Ischemic stroke

  • Usually no hemorrhagic complications (unless concomitant autoimmune thrombocytopenia)

  • Responsive to antiplatelet therapy and/or anticoagulation

  • DADA2: deficiency of adenosine deaminase 2; HBV: hepatitis B virus; HCV: hepatitis C virus; TNF: tumor necrosis factor.