[Differential diagnosis of aortitis].

Aortitis are mainly described in inflammatory disorders such as Takayasu arteritis, giant cell arteritis or Behçet's disease. Aortitis is sometimes qualified as idiopathic. However, differential diagnoses must be searched since they need specific interventions. Infectious aortitis should be ruled out first as its rapid evolution and short-term poor prognosis makes it a therapeutic emergency. Furthermore, rarer differential diagnoses should be known as they require specific care that might sometimes differ from the treatment of inflammatory aortitis, such as retroperitoneal fibrosis mostly idiopathic but also secondary to neoplasia or malignant hemopathies. IgG4 related disease, Erdheim-Chester disease and inflammatory abdominal aortic aneurysm due to atherosclerosis are other differential diagnoses to mention in the presence of aortitis in order to adapt patients' care consequently.