Last Updated on 2nd February 2024 by Caroline Haye
Shedding light on phototherapy
Ever since my vitiligo started to re-pigment some years ago, with the aid of nutritional supplements and sunshine, I have been fascinated by both elements of my recovery. I have written a lot about the nutrition involved but, until now, very little about sunshine or UV light . So, this week I am going to rectify that by answering the question, what is narrowband UVB? And why is it so helpful as a vitiligo phototherapy treatment?
Narrowband UVB is the type of light doctors most often prescribe nowadays in treating vitiligo (as well as psoriasis and eczema). And it is what I used during the winter months… So that my rapid re-pigmentation during the spring and summer of 2010 could continue at the same rate even without the benefit of sunshine.
I’ve never been quite clear what narrowband UVB light actually is. So I 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…
What you really find at the end of the rainbow
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 are wondering just what is so red or violet about them, keep reading.
The discovery of infrared light
In the year 1800 Sir Frederick William Herschel, a musician and astronomer, made an interesting discovery. He discovered that different colours possess different degrees of heat. (Strange as that may sound to the non-scientists among us).
By splitting sunlight into its component colours (i.e. a rainbow) he was able to measure these different temperatures. And what he found was quite fascinating… As you progress from the violet end of the spectrum to the red end, the colours increase in temperature. Not satisfied with that, he also measured the temperature in the region just beyond the red portion of the visible light. And he found that this invisible region had an even higher temperature. This was how he discovered an invisible form of radiation beyond red light. A form which, logically enough, gained the name “infrared” light (“infra” meaning “below”).
Ultraviolet light
Just one year later, inspired by Herschel’s discovery, physicist Johann Wilhelm Ritter decided to conduct his own experiments. He wanted 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, while you can’t actually feel it, is responsible for the tanning process… The 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.
Wavelengths
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 an everyday perspective, is that both wavelengths can be harmful to anyone who has too much exposure. Excess exposure to UVA rays age us. Too much UVB burns us. And overexposure to either one can lead to cancer.
UVA rays penetrate deep into the dermis. This is 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.
What is PUVA?
PUVA 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 is more beneficial in skin therapy than broadband. So this is why it is the most popular and effective light treatment today.
My own experience of narrowband UVB therapy
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 exposed to sunlight began producing freckles… Which then multiplied and started to join up. (See Pictures Of My Vitiligo.)
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 it achieved a darker colour overall than the sunshine alone had done. (Too dark really, given that it was quite blotchy at that stage. But it did even out eventually after the UV treatment ended).
My personal verdict on nb UVB
So, I would have to say that, based on my own experiences, the amount of UVB present in natural sunshine can be enough to re-pigment vitiligo… As long as you correct any nutritional deficiency at the same time. But, having said that, I found that nutrition plus narrowband UVB produced even faster results, probably because the wavelength was more targeted and because the exposure times were scientifically regulated, rather than random. 🙂
