A couple of weeks ago, I disturbed a wasp nest. Wasps attack immediately when they feel threatened and I was stung 10-15 times on my arm, hand and leg. I couldn’t get away because of the long grass and brambles. It didn’t hurt much initially, so I carried on working. Then I started to feel a ferocious itching and burning in my groin, which I knew was lymph and I decided to head back to the cabin. Before I got back my scalp, palms and the soles of my feet were on fire. Within minutes my whole body was covered in a painful red rash and I jumped in the shower and turned on the cold water to try and give myself an adrenaline boost. It didn’t seem to work.
Dean found an anti-histamine, which I was reluctant to take, but I could see he was worried. By this time, my face was really swollen and the pain was intense. I put me feet in a bucket of cold water and had Dean rub me all over with St John’s Wort oil to try and cool me down. Then my throat started to close and Dean wanted to know if we needed to go to the hospital. I had a moment of fear and thought: take me now or make this go away and the swelling in my throat began to ease and the pain became more bearable. I was still nicely swollen two hours later when Claudius and Michelle showed up, but managed to get out of bed a bit later so we could go out to dinner. It took several days for all the swelling to go completely.
Since then I’ve been wondering why I had such a strong reaction and why did I not want to take the anti-histamine? I don’t like pharmaceuticals and consider them to be more harmful than beneficial in most cases, excepting emergencies; and this was an emergency. I don’t think Sophia set up this experiment with the intention that we should succumb so easily to insect stings either, although poisons definitely have their place. However, histamine is not a poison, it is a neurotransmitter, so why do we need to shut it off?
A neurotransmitter is a chemical that is released by neurons in the nervous system and crosses the synaptic gap between neurons, to be received by another neuron in order to generate a specific reaction. The constant stimulation of neurons causes reactions in the body which are specific to the type of neurotransmitter that is passed. Histamine’s role is to produce an immediate inflammatory response as part of the immune system that comes into action when your body is under attack. Histamine causes the blood vessels to swell, so that white cells can get to the problem area quickly, that sounds like a good thing. Over-reaction, like mine, is considered to be the result of histamine intolerance, due to the body not being able to break down histamine properly. We always have a small amount of histamine circulating in the body and when I was stung, more was released at the site of the the wasp stings, flooding my body.
The exact composition of wasp venom is unknown. From the wasp’s perspective, it stings to paralyse other insects that it wants to eat, or to warn off larger animals like me. Wasps have been around for longer than humans and they are very effective predators, see Wasp Warriors. However, it is not the poison that causes the allergic reaction. Wasp venom contains a protein enzyme called hyaluronidase, which speeds up the dispersion through the body of any injected substance, by reducing the viscosity of hyaluronic acid that cushions the cells and increasing tissue permeability. (Yes, hyaluronidase is used to break down hyaluronic acid based cosmetic fillers after people have had too much of it pumped into their faces to make them look younger!) My allergic reaction was caused by the combination of hyaluronidase and histamine, which generated a systemic inflammatory response and the anti-histamine probably helped in this situation. Adrenaline also stops the production of histamine, which is why people who know they are highly allergic carry Epipens.
But why do I have too much histamine in my body? There are many foods that contain histamine (and these foods are often involved in food allergies) but my intolerance most likely stems from the fact that I was on Zantac for 25 years, because of a stomach ulcer. Zantac/Ranitidene, like its cousins Tagamet and Pepcid is a histamine blocker. It targets the H2 histamine receptors, which are found in the stomach lining, heart, uterus, vascular smooth muscle cells and white blood cells. It stops these cells responding to histamine, so that there is no inflammatory response from food or drink that would normally cause irritation. The body naturally responds by producing more histamine, causing a permanent overload. In addition these drugs, and others, actually deplete the levels of diamine oxidase in the body, which is primarily responsible fro breaking down histamine in the digestive tract. I weaned myself off Zantac in 2010 and have had no pain or bleeds since and I’m able to eat and drink more liberally than I ever was while on Zantac. I now need to look into how to reduce my baseline histamine levels – more on that in another post.
Apparently, most people who get an allergic reaction to wasp stings do not get it for bee stings, or vice versa. It’s one or the other, so that’s a relief!