Hello, Steroids often cause neurologic symptoms of a mild degree. Cannot say in your particular case, but generally, inflammation persists for weeks after infection. Infection with atypical bacteria such as whooping cough, will not be treated by all antibiotics and will give a non-productive cough. On the other hand, asthma, allergies, tumours, growths, ACE inhibitors, dust and inhaled substances are some of many things that cause lung inflammation without infection. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Matt Wachsman, Addiction Medicine Specialist