I see lots of cases of hives and I’m often struck by how many have been previously seen in an emergency department for control of their outbreaks. I also frequently see patients for evaluation of hives when their rash is something altogether different. So, dear reader, here is a quick primer on what to do if you get hives.
First, make sure it’s hives. Hives can vary somewhat in appearance, but generally are dime sized to half-dollar sized and have a red rim with a clear center. If you get a bunch of them together, called coalescence, they can look much bigger. Hives are itchy. Some people say they burn a bit, but most describe intense itching. The key factor in figuring out if a rash is hives is duration. Individual hives only last minutes to a few hours. Outbreaks can go on much longer, but the individual spots are fairly short lived. If it’s in the same spot for a day or more, it’s not hives.
Although allergic reactions can cause hives, most hives are non-allergic. If you have a true food allergy, medication allergy, or bee sting allergy and you have an obvious exposure to your trigger, then you need to follow your own doctor’s advice on immediate treatment and seeking medical care. If you break out in hives and experience symptoms such as difficulty breathing or swallowing, tongue swelling, or lightheadedness and dizziness, then you need to seek immediate medical help as these can be signs of anaphylaxis. If, however, you experience strictly skin symptoms, you can usually treat yourself with simple antihistamines.
Benadryl works well, but it is very sedating and also only lasts a few hours. I usually recommend cetirizine or fexofenadine,which used to be known as Zyrtec and Allegra, respectively. They are both effective, low- or non-sedating, and last all day. Be aware that cetirizine makes about 15% of people sleepy. I have found loratidine to be less effective than the others.
When treating your hives, remember a couple of things. First, it takes an hour or so for the antihistamines to get in your system after you swallow them. Don’t expect them to work in fifteen minutes. Second, you may have to take a larger than recommended dose. Antihistamines are dosed for the nose and the amount of histamine released in a hives outbreak can be much larger than that released in a sneezing attack. If one cetirizine or fexofenadine hasn’t worked in an hour, take a second one. If your hives resolve, you might want to consider continuing a long-acting antihistamines once or twice a day for two weeks to fend off any recurrent bouts.
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