Allergies and colds cause very similar symptoms. Colds are caused by a viral infection, and symptoms often last up to two weeks while your body’s immune system tries to defeat the virus. Sometimes, the nasal mucous color starts out clear, but then it often turns cloudy and/or discolored before it eventually goes away. Sometimes a virus is accompanied by a fever, headache and muscle aches. Allergies are genetic hypersensitivity that causes a reaction when a person is exposed to something. As a person breathes in the allergen, the immune system over-reacts and causes symptoms of itchy eyes, such as sneezing, congestion, or runny nose. Allergy symptoms can last for several weeks or months, and in some people can occur year-round. Typically, the nasal discharge is thin and watery and allergies do not cause fevers. Fortunately, allergies can be easily diagnosed with skin tests and can be treated with allergen avoidance and/or medications, including immunotherapy, a series of desensitization injections.