Raised, itchy welts that last less than 24 hours in any one spot are typical.

HIVES/URTICARIA

Hives (aka urticaria) is a common, itchy, allergic condition of the skin. Below are the approximate percentages of important causes.

Cause of Hives

• Idiopathic (cause unknown): 50%
• Viral infection, e.g. cold: 40% (closer to 50-60% in chidren)
• New medication: 5%
• Food: 3%

All patients with new onset urticaria have by definition "acute urticaria". If the urticaria lasts longer than 6 weeks, it is called "chronic urticaria". About 20-30% of acute cases go on to chronic, but it is impossible to know at the outset which. Fifty percent of cases of chronic urticaria will be gone in 1 year. 80% will resolve in 5 years.

Other Key Points

• Urticaria is twice as common in women than men.
  
• Urticaria is common. About 20% of people will experience at least one episode of hives in their lifetime.
• Significant swelling of the skin and/or underlying tissue is called angioedema and can be serious. Seek help immediately if you experience angioedema.
• Rarely hives may be triggered by heat, cold, pressure etc. These are called the physical urticarias.

What questions to ask yourself if you have new onset Hives/Urticaria.

• Have you had a cold or otherwise been sick recently?
• Did you start any new medication, vitamin, supplement or any pill recently?
• Have you recently traveled outside of the country (refers to risk of parasitic infection)?
• Can you think of anything that might have brought on the hives?
• Do any parts of your body swell, e.g. lips, eyes, tongue?
• Do you have any dental problems that need attention?
• Do you experience any of the following with the hives: nausea, diarrhea, abdominal pain wheezing, difficulty breathing, joint pain or swelling, headache?
• Do any of the following seem to cause the hives: aspirin, certain foods (e.g. red meat) alcohol, any medications.
• Do any of the following seem to cause the hives: pressure, sunlight, rubbing, scratching, exercise, heat, cold, vibration, water
• Do you have any of the following medical conditions? thyroid disease, rheumatoid arthritis, celiac disease, and type 1 diabetes.

Let your doctor know if the answer to any of the above is yes.

Do you need blood work?

The yield with blood work is low, especially for acute urticaria. For chronic, your doctor may get some screening blood work which may include: blood count, urine analysis, vitamin D and a liver test. If there is recent travel to a tropical country, stool sample for ova and parasites may be ordered.

Treatment, Brief Overview

What to avoid

Aspirin and non-steroidal antiinflammatory drugs e.g., Alleve (naproxen), Advil (ibuprofen) can worsen urticaria so you may want to avoid these. Tylenol (acetaminophen) is okay.

Antihistamines

Over the counter antihistamines are the mainstay of therapy. They should be taken daily to prevent the hives. The goal is the complete elimination of the itch. So-called second-generation antihistamines are best (least sedanting) and are listed below. The starting dose is one pill a day.

• Allegra (fexofenadine) 180 mg
• Zyrtec (cetirizine) 10 mg
• Claritin (loratadine) 10 mg

Pick any of the above and start with one pill a day for 3 days. If the rash is suppressed, great. Continue taking one pill a day. If not, add in a second pill, e.g. one pill morning and night. Do that for 3 days. Again, if the hives are not controlled, add in another pill etc. till you get to 2 pills twice a day. In the majority of cases, this approach is successful in suppresses the hives and/or itch. If not, let your doctor know. The main side effect of the above approach is drowsiness. Allegra is preferred as it is--for most people--the least sedating.

First generation antihistamines like Benadryl (diphenhydramine) are okay, but they are much more sedating, so best to avoid, unless taking at night.

Additional Pictures

You may get red lines where you scratch. This is called dermatographism.

RegionalDerm

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