There are many things capable of causing itchy eyes. Among the most common are allergies and a condition called conjunctivitis. Some people can also develop itchy eyes when they have a common cold. Since these conditions can be similar in some ways, determining the cause of the itching can be confusing. The other symptoms common to these conditions often help distinguish them.
Allergies are among the most common causes of itchy eyes. When a person has an allergy, their eyes may become red, watery, and itchy. A person with allergies may also develop other symptoms, such as sneezing; stuffy or runny nose; cough itchy rash; and itchy throat or ears. Allergies are not contagious.
Many people develop itchy eyes due to seasonal allergies, but other types of allergies also cause this problem. For example, a person may have itchy eyes due to an allergy to pollen, pollution, or pets. Some people are also allergic to dust and mold. A person may even develop itchy eyes in connection with a food allergy.
Conjunctivitis is also among the most common causes of itchy eyes. Marked by red, itchy, and irritated eyes, this infection is often caused by a bacteria or virus. It is sometimes associated with allergies and exposure to irritating substances as well. In addition to general itching and irritation that are similar to allergy symptoms, conjunctivitis can also cause symptoms such as tearing, yellow discharge from the eyes, a burning sensation, blurred vision, and sensitivity to light. Also, conjunctivitis caused by a virus or bacteria is usually contagious.
The common cold can also cause itchy eyes in some cases, and this fact can make a cold difficult to distinguish from an allergy. However, the two conditions are very different. A cold is caused by a virus and can be spread from person to person as long as the allergy is not contagious. Similarly, a person may develop a fever and aches and pains when they have a cold, but they are unlikely to do so in relation to an allergy.
Colds and allergies also differ in how long they last. A cold often lingers for a week or so, but an allergy can last an entire season or affect a person through all four seasons. However, in some cases, an allergy can only produce symptoms when the person is exposed to an allergen, such as a cat and its dander. A cold, on the other hand, will likely produce symptoms even after the person is no longer around the cat or her dander.