Question: Our pediatrician documented that a patient had an “unexplained cough.” Do I need to query for more information? Iowa Subscriber Answer: Even though “unexplained cough” seems vague, there is no need to query the provider in this instance. Though you may not associate “unexplained” with “chronic,” take a look at the synonyms listed under R05.3 (Chronic cough) in the ICD-10 Tabular List: persistent cough, refractory cough, and unexplained cough. This means that if your physician documents that a patient has a persistent, refractory, or unexplained cough, report R05.3.