Physicians arbitrarily divide hives into acute (new or periodic episodes lasting fewer than 6 weeks) and chronic (periodic episodes lasting more than 6 weeks). Though many people have a single episode of acute hives that goes away within a few days to weeks, some individuals may have chronic hives that persist intermittently for years. More often than not, the offending agent is never identified in those who suffer from chronic hives.
Hives can be triggered by many things, including:
- Medications, especially aspirin, ibuprofen, naproxen, narcotic painkillers, and antibiotics Infections with viruses, bacteria, or fungi
- Environmental allergies such as insect bites, pollen, mold, and animal dander
- Physical exposures such as heat, cold, water, sunlight, and pressure
- Medical conditions including some blood diseases and cancer
- Food allergies such as from strawberries, eggs, nuts, and shellfish
Acute hives are most common in children and young adults, and chronic hives are more often seen in females, especially middle-aged women.
Hives are very common; it is estimated that up to 20% of the population may develop them at some point in their lives.
- Upper arms or upper legs
- Hands and feet
Dermographism is a type of urticarial reaction that appears within a few minutes of scratching the skin. The rash is usually seen in a straight line (linear) pattern. This is usually a sign of a person with sensitive skin.
Swelling of the eyes, mouth, hands, feet, or genitals can sometimes occur with hives. This swelling, called angioedema, usually goes away within 24 hours, but it can be quite severe and life-threatening when swelling of the airway occurs.
Usually itchy, hives can also burn or sting.
- Take cool showers.
- Apply cool compresses.
- Wear loose-fitting clothes.
- Avoid strenuous activity.
- Use an over-the-counter antihistamine such as diphenhydramine or loratadine.
In non-urgent situations with hives, see your doctor if the hives do not improve with treatment or if they continue to appear for more than a few days.
Before visiting your doctor, try to notice what might be triggering your hives and whether it improves or worsens with exposure to heat, cold, pressure, or vibration. Take a list of every medication (prescription or over-the-counter), supplement, or herbal remedy you may have taken recently. Also, recall any recent illnesses you may have had since some illnesses (or their treatments) can trigger hives.
Obviously, the best treatment for hives is to discover any triggers and stop your exposure to them. However, most people with hives do not know the cause, and they require medications to get rid of them.
The most common medications for hives include:
- Sleep-causing (sedating) type-1 antihistamines such as diphenhydramine or hydroxyzine
- Non-sleep-causing (non-sedating) type-1 antihistamines such as loratadine, fexofenadine, desloratadine, or cetirizine
- Type-2 antihistamines such as ranitidine, cimetidine, or famotidine
- Montelukast, zafirlukast, or zileuton