Little one (2 1/2) has had none stop colds since starting nursery. He has just got over the last one about a week ago. Since then he has still had a cough but only at night. He will start coughing every night and it will last for about ten mins at a time, he then gets really distraught. The last few times I've been in to check on him when he's having these episodes his lips and all around them have been blue. He no longer has a temp or any other sign of the bug he had but it's worrying me a bit that this cold won't go. He also has suspected asthma so I'm not sure if it's now that instead of a normal cough?