Glucocorticoids Versus Placebo for the Treatment of Acute Exacerbation of Idiopathic Pulmonary Fibrosis

Inclusion Criteria: 1. Patient is ≥ 18 years of age 2. IPF or IPF (likely) diagnosis defined on 2018 international recommendations 3. Definite or suspected Acute Exacerbation defined by the international working group criteria after exclusion of alternative diagnoses of acute worsening \*The criteria of IPF-AE are as follows: * Previous or concurrent diagnosis of IPF (a) * Acute worsening or development of dyspnea typically \< 1-month duration * Computed tomography with new bilateral ground-glass opacity and/or consolidation superimposed on a background pattern consistent with usual interstitial pneumonia pattern (b) * Deterioration not fully explained by cardiac failure or fluid overload Patients who fail to meet all 4 criteria due to missing computed tomography should be considered as having "suspected Acute Exacerbation". 1. If the diagnosis of IPF is not previously established, this criterion can be met by the presence of radiologic and/or histopathologic changes consistent with usual interstitial pneumonia pattern on the current evaluation. 2. If no previous computed tomography is available, the qualifier "new" can be dropped from the third criterion. 4. For women of childbearing age: efficient contraception for the duration of the study\* \*Effective contraception is defined as any contraceptive method that is used consistently and appropriately and has a low failure rate (i.e., less than 1% per year) 5. Affiliation to the social security 6. Patient able to understand and sign a written informed consent form or in case of incapacity of the patient to a relative whom understand and sign a written informed consent form Exclusion Criteria: 1. Identified etiology for acute worsening (i.e.: infectious disease) 2. Known hypersensitivity to glucocorticoids or to any component of the study treatment 3. Patient requiring mechanical ventilation or already on mechanical ventilation 4. Active bacterial, viral, fungal or parasitic infection. On swab collected, only positive for SARS-CoV-2, Influenzae A, Influenzae B and Respiratory Syncytial Virus (RSV) result, are considered active viral infection. The others viruses (i.e. Rhinovirus, Adenovirus…) are not considered to be responsible of pneumonia. 5. Active cancer 6. Patient on a lung transplantation waiting list 7. Treatment with glucocorticoids \> 1 mg/kg/d from more than 7 days in the last 15 days 8. Patient participating to another interventional clinical trial 9. Documented pregnancy or lactation 10. Patient under tutorship or curatorship 11. Patient deprived of liberty 12. Patient under court protection