When one of my twins has a cold or cough

When one of your twins had a cold or cough, did the other twin also get a cold or cough?

Well, both my twins get a cold or cough at the same time, if not two or three days apart from each other.

Twin "A", had a cough and runny nose two weeks ago. Now, that cold, runny nose and cough, have returned and her sister, Twin "B" has caught her cough and runny nose. Right now, Twin "A" is coughing a lot, but I am not sure if it is croup or not. How do you tell if it is croup?

We have just been giving her OTC medicine.

Hopefully her cold, cough and runny nose will go away before her and her sister's birthday next week.