What are the differences between flus and colds? I don't know about English, but in Spanish they confuse it very often when using words gripe and resfriado.
Maybe it's not the case in English, but I would like to know what are their differences and if you can give a bunch of examples for each one similar to this way: you know that you have flu/cold when...
In addition, both flu, cold and allergies in the nose (e.g. with allergy: dust) have significant symptoms related with the nose. It is many times with mucus, sneezing or stuffy nose.
How can you recognize if it's allergy, flu or cold? I didn't want to take the general case of allergy because not always it is related to the nose.