How to tell whether congestion is caused by a cold, sinus infection or allergies

The symptoms caused by the common cold, sinus infections and allergies overlap somewhat, but there are ways to tell the conditions apart, health experts say. A cold only lasts a short duration and is not accompanied by a fever, unlike a sinus infection. A thick, green or yellow mucus also is an indicator of a sinus infection. Allergy symptoms tend to come and go depending on exposure to pollen, dust and pet dander.