Last revised by Henry Knipe on 27 Feb 2023

Bronchiolitis (plural: bronchiolitides) is a broad term that refers to any form of inflammation of the bronchioles. It is often used in situations where the inflammation primarily occurs in airways smaller than 2 mm 6.  It can carry variable clinical, functional and morphological expressions. The bronchiolar disease may be a primary or a secondary condition.

According to some authors, there is some overlap with the term small airways disease 5.

Radiographic features

Plain radiograph

Usually not detected at chest radiography but may manifest with non-specific findings such as ill-defined small or hazy clustered nodules or areas of air trapping characterized by hyperlucency and/or oligemia 6.


The presence of bronchiolitis is best assessed with HRCT. CT features include one of a combination of


One method of classifying various forms of bronchiolitis is as follows 1:

Exact radiographic features are best discussed under each sub-topic.

Other specific forms according to underlying pathology include:

See also

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