There are many things capable of causing itchy eyes. Among the most common are allergies and a condition called conjunctivitis. Some people may also develop itchiness 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 to distinguish them.
Allergies are among the most common causes of itching in the eyes. When a person has an allergy, his eyes may become red, watery, and itchy. A person with allergies may develop other symptoms as well, such as sneezing; a stuffy or runny nose; coughing; an itchy rash; and itching in the throat or ears. Allergies are not contagious.
Many people develop itchy eyes because of seasonal allergies, but other types of allergies cause this problem as well. For example, a person may have itchy eyes because of an allergy to pollen, pollution, or pets. Some people are allergic to dust and mold as well. A person may even develop itching eyes in relation to a food allergy.
Conjunctivitis is one of the most common causes of itchy eyes. Marked by red, itchy, irritated eyes, this infection is often caused by a bacterium or virus. It is sometimes associated with allergies and exposure to irritating substances as well. In addition to the itching and general irritation that are similar to the symptoms of an allergy, conjunctivitis may also cause such symptoms as tearing, yellow discharge from the eyes, burning sensations, blurred vision, and sensitivity to light. Additionally, conjunctivitis that is caused by a virus or bacterium 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. The two conditions are very different, however. A cold is caused by a virus and can be passed from person to person while an allergy is not contagious. Likewise, a person may develop a fever and aches and pains when he has a cold but is unlikely to do so in relation to an allergy.
Colds and allergies differ in terms of their duration as well. A cold often sticks around for about a week or so, but an allergy can last for an entire season or affect a person through all four seasons. In some cases, however, an allergy may 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 its dander.