Urticaria (hives) and Angioedema

Urticaria (hives) and angioedema (swelling of deep skin tissues) are common skin problems which affect approximately 20% of Americans at some time in their lives. Hives are itchy, red, raised, well-demarcated skin eruptions with pale centers. Typical hives are of variable sizes (from pimple to palm size) and shapes. Individual hives frequently merge to form larger hives. Angioedema can appear as swelling of the eyelids, lips, facial area, throat, hands/fingers, genitals, or feet/toes with no obvious overlying skin rash. Hives and angioedema appear randomly or following an identifiable trigger, last from several minutes to several hours in duration (almost always less than 24 hours), and resolve spontaneously, usually with no residual skin scarring, bruising or skin color changes. Angioedema is typically tingling and burning in sensation, rather than itchy. Hives and angioedema frequently occur in combination, though may occur separately. Urticaria/angioedema can occur as one of several generalized signs of a more severe allergic reaction called anaphylaxis.

The frequency of flares of urticaria/angioedema can vary greatly, from multiple episodes each day to one episode every few years. Urticaria/angioedema can occur as an isolated skin disorder, or, less likely, be associated with other internal disorders, including autoimmune diseases, chronic infectious diseases, thyroid disorders, and rarely, cancer. Other triggers that can cause urticaria/angioedema include foods, food additives/ preservatives, medications, insect bites/stings, airborne allergens [Allergens are substances which cause allergic reactions (e.g. pollens/molds/dust mites).] and radiology contrast dyes. Certain types of urticaria/angioedema can be caused by physical triggers, including cold, heat, exercise, pressure, vibration, sweating, water and sunlight. Recurrent episodes of urticaria/angioedema which last for less than six weeks are classified as acute. Such cases often have identifiable causes including foods, drugs or acute infections. Recurrent episodes of urticaria and/or angioedema which last longer than six weeks are classified as chronic. Up to 80-95% of chronic urticaria/angioedema have no identifiable cause. Some experts in the field of Allergy and Immunology suspect that an internal immunologic mechanism may play a role in a subset of these cases.

Evaluation of patients with hives and/or angioedema includes a thorough history addressing all potential causes, a physical examination, selective skin testing for airborne allergens and foods, and extensive laboratory studies. Skin biopsies are performed when indicated.

Management of urticaria/angioedema need not be a frustrating or difficult experience. If a definite trigger or underlying disease has been identified, the trigger is avoided if possible or the underlying disease is treated as the first step in management. Although a definite trigger or underlying disease is often not identified, medications are usually very helpful in resolving symptoms. Specifically, antihistamines are used as the first choice treatment. One or several antihistamines may be prescribed. These medications relieve itching, promote resolution of existing hives, and prevent evolution of new hives. For patients with infrequent flares of urticaria/angioedema, antihistamines are used on an as-needed basis. For patients with frequent (daily or near-daily) flares, antihistamines are employed on a regular basis. Hives that are resistant to antihistamine treatment can be treated with additional medications. Oral corticosteroids may be used for short-term management of acute severe flares and for long-term management of persistent flares unresponsive to maximal non-steroid medical therapy. When used long-term, steroids are administered on an every-other-day schedule to minimize side effects. In management of life-threatening episodes of angioedema of the throat, epinephrine is administered in addition to antihistamines and steroids.

Fortunately, despite its annoying, frustrating nature, urticaria/angioedema is usually benign and self-limited. With appropriate treatment and guidance from the specialists at The Asthma Center, most patients gain control of their symptoms.