**R05 — Cough** is used as a primary or secondary diagnosis code when cough is the chief presenting complaint and no more specific diagnosis has been established. It applies regardless of duration or etiology.
For productive cough with infection, more specific codes apply (J20.x for acute bronchitis, J45.x for asthma exacerbation). Chronic cough (≥8 weeks) is often re-coded after workup.
Belongs to **Chapter R** — Symptoms, signs.
