Hives – Unknown Causes and Known Treatment

By Heather Legg

This weekend we were with some friends and one of them had a terrible outbreak of hives. The worst part – she had no idea why they were there. Of course, all of us were asking her about everything she had eaten and come in contact with, and nobody could figure out anything.

She said for the past few years she has had mystery outbreaks. For her, they start at her hairline and work their way down her body and end up on her feet. We watched the progression of the breakout of hives around her face and hairline and by the next day, those had gone but her feet were swollen and red. She wasn’t concerned with anything more than the hives, and they didn’t even really itch that bad; she was mostly frustrated with the unknown cause.

As I did a bit of research when we got home, I did find that on her feet it could be something a little different than hives, called angioedema. According to, this is “similar to hives but the swelling occurs beneath the skin instead of on the surface.” The article mentions a common place for this is the hands and feet (as well as eyes and lips), and it can last longer than hives but usually not more than 24 hours. It can also, though rarely, occur in the airways blocking air flow, similar to anaphylaxis.

Angiodema forms in response to histamine (like hives) and blood plasma leaks out of small blood vessels in the skin, therefore causing the swelling. I’m sure our friend would like to know (or not) that it is common to have the reactions with no idea why, though allergic reactions can occur from anything from foods (meaning anything from a food itself to preservatives and additives), insect stings, sunlight exposure or medicine.

As far as treatment goes, everyone tends to go to the antihistamines first which is recommended. Benadryl can usually be effective, but it is important to take the right dosage. Once Benadryl (or similar form) is taken, there are some other things to do, but it is smart to take medication at onset to try to control the outbreak. To relieve the itching, cool compresses usually help. Because heat can be a trigger, too, cooling down the body can help, either with a cold shower or bath in addition to cool compresses. Relaxing is helpful as well, though sometimes easier said than done. Hives can get worse with stress (which adds heat to the body) so trying to sit and relax during an outbreak is a good idea.

Of course, if the hives are getting to air passages and turning into swelling of the lips, face and/or mouth, emergency medical attention may be necessary in case breathing is at risk.

Often, like our friend, people never learn the cause of their hives or angioedema. This is classified as idiopathic hives. According to the World Allergy Organization, if no cause is found, even with blood tests, it’s not considered a true allergy because no IgE antibody is involved.

“Research suggests that in 35-45% of patients with idiopathic hives the cause may be autoimmunity – that is, the patient’s immune system working against itself. These autoimmune types of hives are not serious and usually respond to treatment with antihistamines.”

Because there can be so many causes, or none at all, for hives and angioedema, the hardest part may be the unknown and the fact that they can’t even be controlled with avoidance, as you don’t even know what to avoid.



I agree, not knowing what to avoid is a pain in itself. I suffer from urticarial (hives) and angioedema and have been unable to identify the cause. I first noticed my hives at a family reunion in Myrtle Beach, SC. Born and raised in Port Arthur, TX, home of the hummingbird size mosquito, I thought I was being bitten by mosquitoes at the time. None of the other people seemed to be bothered by any bugs. Finally, while walking in the light someone noticed my hives. I had assumed for years that the marks that were described to me as hives came from me scratching and not the other way around. Now, I try to document when I have the outbreaks and what foods and activities I did surrounding episodes. I will probably never know the cause, but the scientist in me will continue my study. Good article, thank you.

September 27th, 2013 | 4:08 am

I have been living with severe outbreaks of hives for over 3 years. In the beginning it started at my hairline and would work it’s way down. Mostly, the severe hives where on my palms and the soles of my feet and usually traveled along my main arteries, but not limiting to all over my body. Been tested and found I was allergic to eggs, but nothing else. They took all sorts of blood work and everything came back negative. Looked in Lupus, IgE, Rhuematoid arthritis, MS, etc- all negative. I have eliminated all gluten products, and very limited on dairy. I’ve noticed an increase in hives after I eat clementines and they seem to be the worst!! Now I am thinking of seeing a Holistic MD to see if he could figure it out. My food sources are dwindling.

April 30th, 2016 | 3:13 pm

Have been suffering from massive outbreaks of hives for about 15 years. Usually only last for about an hour but it is often intense. Sometimes starting at my hands and feet and then covering my body. Red wine can often trigger an attack but so can stress. I’m thinking any sudden change in blood pressure leads to an attack which make wonder if indeed this is an auto immune issue. Sure wish there was an answer out there. Attacks are miserable.

August 10th, 2017 | 9:16 pm
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