Shedding light on #phototherapy
Ever since my# vitiligo started to repigment five years ago, with the aid of nutritional supplements and sunshine, I have been fascinated by both elements involved in the process of my recovery. I have written a lot about the nutrition involved but, until now, very little about #sunshine. So, this week I am going to rectify that, which is appropriate because I just spent an enjoyable morning watching the eclipse so the sun is very much on my mind!
In particular, I want to explore the subject of #narrowbandUVB because this is the type of light most often used nowadays in treating vitiligo (as well as #psoriasis and #eczema) and it is what I used during the winter months so that my rapid repigmentation during the spring and summer of 2010 could continue at the same rate even without the benefit of sunshine.
I’ve often wondered what narrowband UVB light actually is and decided to do a bit of research to find out. I found the answer quite fascinating, so if – like me – you are not a scientist and would like a quick layman’s guide to where this specific type of light fits in with all the other types, read on!
Just about everyone in the world has seen a rainbow. Many of us first learnt about the sequence of colours in the rainbow by memorising the acronym ROY G BIV (Red, Orange, Yellow, Green, Blue, Indigo and Violet.) But, unless we paid particular attention at school, we may not be aware that the visible spectrum of colours that we see in the rainbow forms just one part of a much larger electromagnetic spectrum. When we talk about light we are usually referring solely to this visible portion of the electromagnetic spectrum (the part that splits into a rainbow when passed through a prism). But, in reality, there are other forms of light that are not visible (like x-rays and gamma-rays) and this is where infrared and ultraviolet come in. If you have ever wondered exactly what these types of light are and just what is so red or violet about them, then this blog post is going to be right up your street!
In the year 1800 Sir Frederick William Herschel, a musician and astronomer, discovered that different colours possess different degrees of heat (strange as that may sound to the non-scientists among us). After noticing that the temperatures of the colours in the visible light spectrum increased as you move from the violet to the red part, he decided to measure the temperature just beyond the red portion of the spectrum where no light is visible. To his surprise, he found that this region had the highest temperature of all. This was how he discovered an invisible form of radiation beyond red light which, logically enough, became known as “infrared” light (“infra” meaning “below”). Just one year later, inspired by Herschel’s discovery, physicist Johann Wilhelm Ritter decided to conduct experiments to determine if invisible light existed beyond the other end (the violet end) of the spectrum as well. Guess what? It did! And this became known as “ultraviolet” (“ultra” meaning “beyond”).
Sunlight contains both IR and UV light. As already explained, neither of these types of light can be seen by the human eye. But IR light is felt as heat and UV, whilst it cannot be felt, is responsible for the tanning process, a protective reaction designed to prevent the UV rays from penetrating into the deeper tissues of our skin. So, this is why UV is the specific type of light used in phototherapy for vitiligo.
So, now we have a better idea what ultraviolet light is, the next thing to mention is that there are three types of UV light: A, B and C (no – I’d never heard of UVC either!). UVC rays are the shortest and strongest of the three, but most people have never heard of them because they are absorbed by the ozone layer and don’t typically reach the surface of the Earth. UVA and UVB, on the other hand, are both present in the sunlight that reaches us. What is the difference between the two? Well UVA has a longer wavelength and UVB has a shorter wavelength. The main difference, from the point of view of someone who likes sunbathing or whose job exposes them to the elements, is that both types of UV can be harmful to anyone who is over-exposed to them. Given too much exposure, UVA rays age us and UVB rays burn us and an excess of either one can lead to cancer. UVA rays penetrate deep into the dermis, the skin’s thickest layer whereas UVB rays will usually burn the superficial layers of your skin. ( On the other hand, of course, without sunlight we would die and moderate sun exposure is essential for the production of vitamin D which maintains healthy bones). The main difference, from the point of view of someone with vitiligo or any other light-responsive skin condition, is that UVB has proven to be much more therapeutically effective than UVA. When I was a young woman looking for an effective treatment for my vitiligo the treatment of choice was PUVA. This is UVA light therapy administered in conjunction with psoralen which makes the skin more sensitive to light. The reason why psoralen medication was needed is that UVA light alone is not very effective, hence the preference nowadays for UVB treatment instead.
If you have followed the story so far, the popularity of UVB in modern phototherapy will make perfect sense. But what about the “narrowband” part of narrowband UVB treatment? Well, there are two types of UVB treatment to choose from: broadband and narrowband. The major difference between the two is that narrow-band UVB units emit a more specific or “narrow” range of UV wavelengths and has been found to be more beneficial in skin therapy than broadband. So this is why it is the most popular and effective light treatment today.
So how crucial was narrowband UVB to my recovery from vitiligo? The quick answer is: not crucial - but it did help speed things up. Within a few weeks of starting to take the nutritional supplements all the vitiligo patches that I was able to expose to sunlight began producing freckles which multiplied and started to join up. This continued throughout the spring, summer and early autumn during which time I was spending around 30 minutes a day in the sunshine at least three or four times a week. As the summer came to an end I asked my doctor to refer me for narrowband UVB treatment, reasoning that this should avoid any slowing of the repigmentation process over the winter. In fact, the pigmentation not only continued during my course of UVB treatment but it accelerated and achieved a darker colour overall than the sunshine alone had achieved (too dark really, given that it was very mottled at that stage but it evened out eventually after the UV treatment ended).
So, I would have to say that, based on my own experiences, the amount of UVB present in natural sunshine is sufficient to repigment vitiligo - as long as any nutritional deficiency is addressed at the same time – but that nutrition plus narrowband UVB can produce even faster results.
My name is Caroline.