ICD-10 Code A37.11 – Whooping cough due to Bordetella parapertussis with pneumonia (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A37.11 – Whooping cough due to Bordetella parapertussis with pneumonia
What it is
This code identifies pertussis caused by Bordetella parapertussis when pneumonia is documented. Use it for a confirmed or clearly documented parapertussis infection with lower respiratory involvement.
Clinical signs
Typical findings include a whooping cough illness with paroxysmal coughing and evidence of pneumonia. Clinical features vary; refer to documentation.
When to use this code
Use A37.11 when the provider documents Bordetella parapertussis as the cause and pneumonia is present. It applies when the record links the cough illness to parapertussis rather than another Bordetella species. If the organism or pneumonia is not clearly documented, check documentation.
Do not use for
Do not use this code for pertussis without pneumonia or for infections due to Bordetella pertussis or other causes. If the diagnosis is uncertain, check documentation.
Coding tip
Code the organism and the pneumonia together only when both are clearly stated in the record.