There are so many "strange" things that come along with chronic illnesses. I say strange, because they are things you wouldn't think apply to the issue at hand, but somehow they do. One of those things is a sensitivity to the sun, or a sun/heat intolerance, which I often see in Lyme patients. I myself have always been someone who loves spending time in the sun, and prior to being diagnosed I had a very tough time at the beach on family vacations. I would spend minimal time in the sun, but every time I did (even if it wasn't even that hot), I had flu-like symptoms hit afterwards. It didn't seem to matter if I spent all my time in the pool never feeling hot at all, the after effects of the sun would be there for the rest of the day irregardless of how I tried to mitigate the heat aspect. This was all prior to being diagnosed, and during a time when I was still able to function relatively normally.
As you can imagine, the sicker I got the lower my tolerance became to the sun. At first I tried to bypass the issue by only getting sun exposure on cool days. But even then the issues arose. I could go outside on a day when it was 55 degrees but the UV index was 8, and even if I spent even 15 minutes outside shivering I would still go inside and develop all the classic flu like symptoms. Basically, this happened devoid of all heat. Heat, or my body overheating, was not the culprit and I knew it. In fact, my hypothesis was further proven when I tried to get my necessary sun exposure via a UV light lamp. I diligently used UV lights, and do you know what happened? Over the course of months I diligently used the UV lights (meant for tanning), and I never got a tan no matter what I did. But the one thing that always happened was the presence of flu-like symptoms.
I started reading about nutritional deficiencies or other things which would prevent someone's skin from tanning. It was the most bizarre thing I had ever experienced in my life, and I knew it tied into my issues with the sun somehow. As the months and years passed I kept pushing myself to try and spend time in the sun because my Vitamin D levels were abysmal. I couldn't raise them with oral supplementation, and it was becoming a big problem in terms of my treatment. I needed optimal Vitamin D levels to have success with the immunotherapy I was doing. So I soldiered through many days of sun exposure, and even with natural sunlight I could still only burn and never tan. And yes, I always felt miserable afterwards.
Well, after years of this madness I finally got some answers! I want to preface this by saying that if you have heat intolerance then just know that this is an entirely different thing. It's also not a sun allergy, so if you have a proper sun allergy then it's also an entirely different thing from that.
So what's happening?
First, let's talk about what cytokines are. If you've been keeping up with the Covid-19 news, you have likely heard of cytokine storms. Many of the sickest Covid-19 patients have high levels of cytokines in their blood, and they tend to massively peak in the evenings, often causing a sudden crash due to a surge of cytokines in what's known as a cytokine storm. Cytokine storms are incredibly dangerous and often fatal. Now, the thing here is that cytokines in and of themselves are good. They are compounds which activate immune cells, and they do good work in small amounts. The trouble arises when they go haywire and start to overproduce. You see this on a smaller scale in autoimmune conditions, where the immune cells are abundant and misfiring so they begin to attack the body. Crohn's is a great example, because in that the immune system becomes over activated and starts to attack the lining of the colon. The same happens with Hashimoto's which attacks the thyroid, and RA which attacks the joints.
Cytokines are great in small doses and where they are needed. But, cytokines also equal inflammation. From WebMD, "A cytokine is a signaling molecule that is secreted from immune cells and certain other cell types that promotes inflammation. Inflammatory cytokines are predominantly produced by T helper cells (Th) and macrophages and involved in the up regulation of inflammatory reactions." Basically, the very mechanism of cytokines comes along with massive inflammation. This is why cytokine storms are so dangerous and can prove to be fatal when they get started. The amount of inflammation that they create is far too much for the body to handle.
Now, going back to the sun. As beautiful as a tan looks it is actually a response to damage being done to the skin. When you go out into the sun your body forms thymine dimers, which damage the DNA in your skin cells. This damage is what can lead to skin cancer if it goes unchecked, but in most cases your body is able to repair the damage itself. When the UV rays hit your skin it triggers cells to create melanocytes to produce melanin. Melanin is the brown pigment which creates the look of a tan, and it is the body's way of protecting the skin from burning/further damage. Basically, the UV rays damage the DNA in your skin cells, therefore your skin is actively making melanin to prevent further damage from occurring.
So, how does the skin repair the damage to the DNA that happened in the first place? It does so by releasing cytokines en masse to start the repair process by telling other cells it's damaged. Basically the cytokines (inflammatory compounds) are released and begin calling on helper cells to come fix the damage that's been done. Now imagine this process happening all over your body which was exposed to the sun. The flood of cytokines is what makes most regular people feel so tired after sun exposure, but for someone with an underlying chronic illness it is much more severe.
You see, on a day to day basis most Lyme patients (and other chronic illness patients) are already dealing with too much inflammation in their body. The mass amounts of inflammation already present on a day to day basis is higher than it should be, and it sets the threshold for extra inflammation quite low. I'll use myself as an example. Although Lyme disease is the main component, it led to several autoimmune conditions as well as mast cell issues. Both of these can come with added inflammation which is a battle to bring down on a daily basis. For myself, and others in a similar situation, it is very easy to set off a cytokine reaction that goes haywire. If I eat a food which I have an intolerance to my body creates so many mast cells and inflammatory agents that I will not only have a stomach ache, but I will also have a migraine and a fever. This is because the inflammatory process in my body has a quick trigger, and a small push can create huge body wide problems. I cover this in length in another post here, but when you already have underlying inflammation issues the threshold to push it over the top is very low. With these patients, when the body calls for cytokines it can't just send a few, it has to send a whole army. It's a bit like barely putting your foot on the gas pedal but being shot out at 100mph.
This is much the same with the sun exposure. The DNA damage calls for cytokines to repair it, but 1. too many cytokines get released at once, and 2. It adds to the burden of inflammation already present, and together this can push it over the edge. And what are some symptoms of body-wide inflammation in the body from too many circulating cytokines? You guessed it, it's pretty similar to how you feel during a flu. Aches, chills, malaise, fatigue, headaches, loss of appetite, fever, etc. In fact, once I learned about this I tried taking Advil (an anti-inflammatory) after sun exposure, and it did actually mitigate the symptoms some.
This is why it's the sun exposure itself, and not the heat, which can cause problems for patients with underlying chronic illnesses. The sun exposure, which in turn creates DNA damage is to blame for the influx of symptoms from UV rays. While it's fair to say that heat intolerance may play a role in some instances and may add to the problems overall, it isn't the main underlying issue if you have problems with the sun specifically.
Some of you may be wondering if I ever figured out why I could only burn (and not tan) from the UV rays. Short answer: not really. It seems like there was some kind of deficiency which was preventing my body from making melanin, and instead I just burned. A burn is simply inflammation, and once the inflammation itself went away I was left with non-tanned skin underneath. As I have gotten better this has improved for me. I tolerate the sun much better now, and I am able to tan. I don't know exactly which specific deficiency caused it, and I wish I knew. But my ability to produce melanin did correlate with how sick I was, so that's pretty interesting to me.
I hope this blog post has been informative to someone out there. I know that being out in the sun is difficult for many patients due to the heat aspect. But sometimes even in the spring or fall time when there isn't as much heat there can still be issues for many people. This should hopefully explain why that's occurring, and bring some clarity surrounding the issue.