Allergies Home > More Details on Zyrtec's Indications
Hives (known medically as urticaria) are red, raised welts on the skin. They are usually quite itchy. Hives are commonly caused by allergies, although other factors (such as stress) can also cause them. Some people have hives regularly without finding any cause for their symptoms. Hives usually respond well to antihistamine treatment, although many of the available antihistamines cause drowsiness. Zyrtec is effective for treating the itching due to hives, often without causing drowsiness.
As mentioned, allergies occur when the body's immune system reacts to normally harmless substances that do not bother most people. This reaction is partly caused by the release of histamine from certain cells in the body. Zyrtec blocks histamine from binding to histamine receptors and causing allergy symptoms. Since histamine is responsible for many of the symptoms of allergies, blocking it can be helpful. It is important to note that antihistamines (including Zyrtec) do not help treat nasal congestion caused by allergies, since this symptom is not due to histamine.
Histamine is also responsible for the formation of hives (whether they are caused by allergies or not). Zyrtec works to alleviate the itching due to hives by blocking histamine.