One of my sons was diagnosed with asthma around the age of three. The prescribed meds did not help and his funny squeaky cough got worse over the next couple weeks. I was talking to my doctor sister. She heard the cough over the phone and immediately diagnosed whooping cough. Tetracycline, as best I can recall, killed the bug, but it took another three weeks for the toxin to get out of his system. I also picked up the cough and picked up Tetracycline and got rid of it.
The moral of early childhood diseases is that diagnoses and recall can be wrong.