Difference between cold and allergies ? runny stuffy nose clear discharge but yellow mucus spit up..scratchy throat..3 days now

Sometimes difficult: but except in very severe cases of allergy, people don't lose appetite with allergy which is also not associated with a fever. Allergy may also be seasonal. Cold is more common when school starts and in the winter, allergy in the warmer months. Cold is not relieved by antihistamine which does reduce allergic symptoms. Itching is not associated with a cold. Hope these points are helpful.

Nostril edges: The neutrophils that are attracted to the tissue injury in a cold will discharge enzymes into the runny mucus and abrade the edges of the nostrils after a day or two. It this happens, consider that you probably have a cold. If it lasts for two weeks, or there's non-cold-like symptoms, get seen.