Table 1

Key features of clinical forms of hypersensitivity pneumonitis⁷

Clinical form	Time frame	Clinical features	Pathology	Findings on computed tomography	Prognosis
Acute	4–48 hours	Fever, chills, cough	Alveolitis	Ground glass infiltrate	Good
Subacute	Weeks–4 months	Dyspnoea, cough	Granulomas, bronchiolitis	Micronodules, air trapping	Good
Chronic	4 months–years	Dyspnoea, cough, fatigue	Lymphocytic infiltration and fibrosis	Fibrosis, honeycombing	Poor