Urticaria, commonly referred to as hives, are raised itchy red lesions of varying size. An episode of hives may last anywhere from hours to weeks and rarely many months. However, individual lesions typically do not last more than twenty-four hours. This is an important distinguishing feature from other itchy rashes.
Hives can have many possible causes. Common triggers include viral infection, food and drug allergies. Food allergies typically occur within one hour of eating the food and will occur each time the food is ingested, even with small portions. Drug allergy can develop at any time, even during the middle of a course of treatment.
Food allergy triggers for hives will usually be obvious because hives will occur only for a matter of hours after eating the suspect food and will not occur again until eating that same food item. Hives resulting from antibiotic allergies will sometimes linger for weeks. Allergy skin tests can confirm food allergies. Unfortunately, there are no commercially available reliable tests for drug allergies.
Frequently, hives occur because of an internal chemical imbalance. In this case, there is no allergy or other trigger causing the hives. These types of hives are called idiopathic urticaria.
Regardless of the cause, most hives respond to treatment with antihistamines. Occasionally, stronger medicines such as oral corticosteroids are needed for brief periods.
In 2014, a novel biologic drug, Xolair, was approved by the FDA for use in cases of chronic idiopathic urticaria. This is the most expensive medication for chronic hives but it is much safer than chronic oral corticosteroids.
Authored by Robert Settipane, MD