Pruritus is the medical term for itching. It is an annoying and uncomfortable symptom that occurs as part of many of the body’s defense processes when exposed to certain chemicals, irritants or allergens that can cause it harm. It also is a symptom for many medical conditions when it affects the skin or the mucous membranes.
Allergic rhinitis and conjunctivitis are disease states that occur when an allergic person gets exposed to allergens and causes nasal and eye symptoms of itchy eyes and nose, watery eyes and runny nose. The scratching and profuse drainage are meant to help the body get rid and wash off the allergens or irritants. However, this annoying and bothersome symptom can be severe enough to cause the affected person to cause injury to the skin and membranes around the eyes and nose due to persistent and relentless scratching of the areas.
Pruritus or itching in the setting of allergies is caused by the release of histamine that is released by mast cells and basophiles, the major reservoir of histamine in our bodies, during the allergic reaction. The histamine released binds to histamine receptors in the membranes which stimulate nerve endings to cause the itch sensation. Sometimes the itching is severe enough to be perceived as pain by severely allergic patients.
Histamine blockers or antihistamines are medications that relieve itching from allergies by binding the histamine receptors thus preventing them from stimulating the histamine receptors thus offering relief from itching.