Atypical pneumonias are characterised by a lack of exudate into alveoli. Instead, the interstitium of the lung is inflamed with a polymorphonuclear cell influx. Typically, consolidation is lacking and chest radiograms are patchily and densely shadowed out of proportion to the severity of clinical features.
Atypical pneumonias include those of:
- chlamydial pneumonia
- coxiella burnetti pneumonia
- Legionnaire's disease
- mycoplasma pneumonia
- pneumocystis carinii pneumonia