Persistent cough - red flag symptoms The red flag symptoms that may indicate a more serious cause of a persistent cough, plus investigations to perform and possible causes. by Dr Pippin Singh Sign in to continue Sign In Email address Password Stay signed in Trouble signing in? Reset password: Click here Need help? Email us Register FREE Limited free articles a month Free email bulletins Register Now Register Now Take a 30-day trial Join MIMS now and pay nothing for the first 30 days Join GPOnline now and pay nothing for the first 30 days Sign Up Sign Up