Family doctor

Overview

• Hives are also known as urticaria
• They affect one in four people at some time in their lives
• Chronic hives can last for years and affect about 3 percent of the population
• In most cases there is no known cause for hives but they can be a reaction to a food, medication, virus, or an environmental allergy
• Avoidance of possible triggers helps to limit hive eruptions and antihistamines can also be useful

What is it?

Hives are also known as urticaria which is an allergic reaction which causes red welts on the skin.

In most cases there is no known cause but they can be a result of an allergic reaction to food, medication or a virus or insect bite.

Hives affects one in four people at some time in their lives. They often appear in children as a reaction to an allergen in the environment.

They cause red, itchy, and inflammed areas of the skin in different shapes and sizes.

Urticaria can be defined as acute, chronic or physical.

Acute:

Acute urticaria is the most common hive eruption. It normally occurs in young patients who suffer from allergies, and appear as a reaction to a food, medication or a virus. The hives will normally fade within six weeks.

Chronic:

Chronic urticaria occurs when the hives last from months to years, and is characterized by flare-ups with symptom-free periods in between. It and affects about three percent of the population. Those who have had the condition for six months or more have a 40 percent chance they will continue to suffer from the condition 10 years later. It is more common among middle-aged women aged 40-65.

Several recent studies have found up to 60 percent of people with chronic urticaria have an autoimmune condition which causes the hives. When a part of the patients own blood is injected into their skin, a hive occurs suggesting the patients own blood can trigger a hive eruption.

Physical:

Physical urticaria involves hives that appear due to certain stimuli.

Physical stimuli can be cold, heat, sun exposure, vibration, pressure, sweating, exercise and many others. In patients with physical urticaria, the hives usually occur at the site of direct

Angioedema:

This causes tissue inflammation similar to hives but it involves deeper skin tissues and tends to last longer than hives. People with angioedema often develop swelling around their eyes, lips, hands and feet. The condition can be dangerous if it obstructs the airways.

What are the symptoms?

Hives can look like red or pink welts on the skin. The skin may be raised and itchy.

They erupt in clusters and mostly appear on the trunk, although they can appear on any part of the body. They measure 1-5cm across and can join together to form larger areas of swollen skin.

The hives will normally fade within 48 hours as new clusters appear in other parts of the skin.

What can be done?

If the hives are a reaction to a food or medication, then elimination of the trigger will resolve the condition.

Most cases of hives will disappear within a few days without any treatment.

Antihistamines can help to limit swelling and relieve itching. Calamine lotion can also help ease itching.

Steroid medication is used in some cases but long term use of steroid is usually not recommended because of the possibility of harmful side effects.

Some medications used to treat other serious tissue diseases such as lupus and rheumatoid arthritis have been used in cases of severe chronic urticaria but these drugs also have unwanted side effects.