Esme that sounds similar to DS yet he was diagnosed asthmatic (triggered mostly when sick with even common cold, and appears to be seasonal) We used a preventer for a year which helped a lot.

From what I've read the two are very similar re symptoms (hence all the diagnoses probably!) and are essentially treated the same, with a reliever and predmix if needed. We have it in the fridge too but haven't needed it for ages now.

It's important to find a gp you trust tho, and then I guess it's to that doctors discretion as to how to treat recurring croup/asthma symptoms.