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Ultraviolet Light

Ultraviolet light is the term used for non-visible wavelengths of light that are just beyond the "visible violet" end of the spectrum. There are several ways used to categorise the different wavelengths within the ultraviolet spectrum, but for this article we will stick with the most commonly used terms which are Ultraviolet A, Ultraviolet B and Ultraviolet C. The earth's atmosphere actually blocks much of the ultraviolet wavelengths emitted by the sun from reaching us.

For medical usage we are most interested in Ultraviolet B (otherwise called UVB), and will therefore first deal as briefly as possible with the other two areas mentioned.

Ultraviolet A

This is also referred to as UVA, UV-A, long wave or black light. It refers to wavelengths of Ultraviolet light between 315nm (nanometres) and 400nm. It creates fast tanning of the skin by causing the skin to oxidise any melanin (a pigment) that was already present in the body. UVB is the wavelength that actually stimulates the body to produce more melanin. Ironically the melanin is a defence response by the body to actually block UV radiation from damaging deeper skin tissue. Your ability to "mount this defence" in the form of tanning is largely dictated by genetics.

In the past UVA was considered the safer form of ultraviolet light, and whilst it appears to be responsible for less cancer concerns than UVB, it causes melanoma, which is by far the most dangerous type of skin cancer. UVA light penetrates the skin deeply, destroys Vitamin A, and can cause indirect DNA damage. It does not cause reddening (erythema) of the skin so making it harder to measure possible damage to the skin from exposure.

From a beneficial view it is still sometimes used for the treatment of acne, although in our opinion we think there are safer and more efficient wavelengths within the red and blue spectrums for helping acne, but it does certainly have a short-term positive effect. UVA is also used in the treatment of neurodermitis and also as a "Woodlight" which is only used for diagnosis of skin conditions (it is not a treatment). UVA handheld lamps are also available on our website or by "special order".

PUVA Treatment

PUVA treatment is the usage of UVA light in combination with psoralens (drugs) to make the skin hyper-photosensitive and is effective in the treatment of psoriasis. However aside from any concerns about the UVA, the number of treatments must be carefully monitored and restricted over the lifetime of a patient due to the potential of liver damage caused by the psoralens.

Ultraviolet C

This is the wavelength of light between 100nm (nanometres) and 280nm.
It is used mainly for sterilization in laboratories and medical facilities. DNA in living organisms absorbs ultraviolet radiation best at peaks of around 185nm and 265nm. It is commercially easier to produce UVC lights that emit around the 254nm level and so this is most often used. The effect of the UVC radiation may not directly kill the organism but damage to the DNA will stop it replicating. Some modern water treatment plants also now use UVC.

Ultraviolet B

This is the area of greatest interest for most of our customers. It refers to wavelengths of light between 280nm and 315nm, and therefore also sometimes called medium wave ultraviolet light. It is these wavelengths that have been proven as effective for the treatment of skin disorders such as psoriasis, vitiligo and atopic dermatitis (eczema). Historically in the early days of UVB treatment the bulbs used emitted the full wavelengths between 280nm and 315nm and these tubes are still called "broadband" UVB tubes. These wavelengths include those proven to be therapeutic but also the shorter wavelengths that cause reddening (erythema) and even burning of the skin. These undesirable wavelengths, (those below 305nm), that cause the erythema increase the risk of skin cancer, cause discomfort and of course limit the amount of treatment that is possible. The more modern answer since the 1980's has been the usage of "narrowband" UVB tubes. These only emit UVB light at around the 310nm to 313nm wavelengths but are still very effective for the treatment of skin disorders. The treatment times for narrowband UVB tubes are slightly longer than for broadband, but this can also be simply counteracted by the use of more tubes.

Ultraviolet Light and Vitamin D

The skin produces Vitamin D in response to exposure to UVB waves primarily in the 285nm to 315nm range. In 2002, Dr. William B. Grant published an article claiming that 23,800 premature deaths occur in the US annually from cancer due to Vitamin D deficiency. This is higher than 8,800 deaths that occur from melanoma or squamous cell carcinoma. Other research estimates that 50,000–63,000 individuals in the United States and 19,000 - 25,000 in the UK die prematurely from cancer annually due to insufficient Vitamin D. The latest research study from Dr. Richard Setlow of the Brookhaven National Laboratory in New York shows that Vitamin D appears to protect against tumours of the breast, lung, colon and prostate.

Our opinions

Medical science is continually evolving in both opinion and treatments with respect to ultraviolet light. In consideration of the data currently available we take the following viewpoint with regards to UV light exposure and phototherapy, but must stress that this is only our current opinion and each person must make their own decision.

1. UVA Light for Tanning

As tanning is purely for cosmetic reasons we would not endorse its usage when viewed against the possible long-term side effects.

2. Acne Treatment with UVA light

We think that the red and blue light treatments offered are a safer and more effective light based treatment with little or no side-effects, and would therefore not recommend UVA light.

3. Psoriasis Treatment with PUVA light

This is currently only available under strict medical supervision and therefore not an option for home treatment. We would never seek to override the medical advice of your dermatologist or medical practitioner but it does appear that even at clinical level narrowband UVB treatment is gradually replacing PUVA as the treatment of first choice, due to it having much fewer side effects.

4. UVB light for Vitamin D production

New research is showing the many benefits of adequate and healthy levels of Vitamin D, and also showing the severe downsides of Vitamin D deficiency. For thousands of years the human body evolved to produce Vitamin D from sunlight and strengthen bones. Regretfully in the Northern Hemisphere between October and May the sun is low in the sky and the sun's rays are so well filtered by the atmosphere, that very little Vitamin D can be manufactured by the body. We endorse the opinion of Dr. Thomas Stuttaford that the answer is to be outside without sunscreen long enough to absorb some summer sun and therefore produce stores of Vitamin D3. As Joanna Owens, senior science information officer for Cancer Research recently stated "A little bit of sun goes a long way. The amount of exposure you need to top up your Vitamin D is always less than the amount needed to tan or burn, which increases the risk of skin cancer".

5. UVB Light for Psoriasis, Vitiligo and Atopic Eczema

As detailed above, we consider narrowband UVB units that produce wavelengths around 311nm are the safest option when compared to broadband UVB or even PUVA treatment. This is because the narrowband avoids the burning (erythema) UVB wavelengths more commonly associated with skin cancers and also avoids the UVA that is linked to the most dangerous melanoma skin cancer. We appreciate that in an ideal world all UVB treatments would be 100% supervised by a healthcare professional at a clinic or hospital, but we also respect the individuals right to seek the convenience of private treatment at home. Ultimately UVB light is available to everyone just by walking out their door in summer, and we therefore feel that a sensible home treatment plan with the correct equipment and operating guidelines, may actually be safer than unmonitored exposure to direct sunlight. We are aware of psoriasis sufferers that book two-week holidays in the sun, just to seek some relief from their condition. Aside from the cost, inconvenience and exposure to undesirable wavelengths it just seems unhealthy to force your body to a sudden two-week session of strong UV light therapy from the sun, and then allow the psoriasis to gradually return over the following months.


In our opinion, which is also that of many medical professionals, it seems safer to maintain a consistent low level of UVB narrowband exposure at home, and to keep these unpleasant skin conditions under constant control as much as possible. Perhaps years from now other treatments for these conditions will be available, but at the time of writing it seems clear that narrowband UVB is the best option for those that wish to treat their condition with some form of ultraviolet phototherapy.

Note: Please note that the above article is just our opinion, although if you are aware of any errors in the above please do contact us by email.

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