Blue is a funny colour; it can bring out different emotions in people depending on the context; Sadness in the Disney/Pixar movie “Inside Out” versus Luke Skywalker wielding a blue lightsaber. (I have firsthand experience of this from having purchased the latter item recently for a certain family member.)
It is also interesting to know that skin cells act differently when different wavelengths (and therefore different colours) of light are shone upon them.
In what way do they act differently?
Studies have shown that blue light can actually reduce proliferation of skin cells.
[Liebmann J, Born M, Kolb-Bachofen V. Blue-Light Irradiation regulates Proliferation and Differentiation in Human Skin Cells. J Invest Dermatol 2010;130:259-69.]
[Mamalis A, Garcha M, Jagdeo J. Light emitting diode-generated blue light modulates fibrosis characteristics: fibroblast proliferation, migration speed, and reactive oxygen species generation. Lasers Surg Med 2015;47:210-5.]
How is that of any use?
Well, there are skin conditions in which there is overproliferation of skin cells, namely psoriasis. In psoriasis which is not too severe, ie there are a few plaques here and there around the body, the treatment options generally revolve around different types of anti-psoriatic creams or gels or foams. Any patient who has limited chronic plaque psoriasis will tell you that all these treatments are generally much of a muchness. Therefore, any new treatment for this type of psoriasis would be greatly welcomed.
Does blue light work in psoriasis then?
There have been a few studies showing that it does improve the plaques of psoriasis.
[Kleinpenning M, Otero M, van Erp P et al. Efficacy of blue-light vs red light in the treatment of psoriasis: a double-blind, randomized comparative study. JEADV 2012;26:219-25.]
[Pfaff S, Liebmann J, Born M et al. Prospective randomized long-term study on
the efficacy and safety of UV-free blue light for treating mild psoriasis vulgaris. Dermatology 2015;231:24-34.]
How does it work?
We know that blue light reduces the proliferation and differentiation of certain skin cells called keratinocytes as well as some other cells and this is what translates into reduction in the severity of the psoriatic plaque. This reduction is, however, transient.
A study has also shown that increasing the duration of exposure to blue light (together with an increase in another factor called fluence) gives the best outcome.
[Félix Garza Z, Liebmann J, Born M et al. A dynamic model for prediction of psoriasis management by blue light irradiation. Frontiers in Physiol 2017;8:28.]
But isn’t giving lots of light dangerous? Won’t it increase my risk of skin cancer?
That is true with traditional forms of light treatment for psoriasis, namely narrowband UV-B and UV-A treatment. This is because they are absorbed by the DNA within the skin cells which then gets damaged.
However, blue light does not induce DNA damage and therefore the risk of skin cancer does not seem to be the same as with traditional forms of light treatment.
[Awakowicz, P, Bibinov, N, Born, M, et al. Biological stimulation of the human skin applying health promoting light and plasma sources. Contrib Plasma Phys 2009;49,641–647.]
So how frequently will I need to get blue light treatment for my psoriasis?
The literature seems to suggest daily treatment with a portable light emitting diode which can be used at home. This contrasts to attendance at a dermatology department several times a week over several weeks as is the case with conventional light treatment.
[Ho D, Koo E, Mamalis A et al. A systematic review of light emitting diode (LED) phototherapy for treatment of psoriasis: an emerging therapeutic modality. J Drugs Dermatol 2017;16:482-8.]
[Pfaff S, Liebmann J, Born M et al. Prospective randomized long-term study on
the efficacy and safety of UV-free blue light for treating mild psoriasis vulgaris. Dermatology 2015;231:24-34.]
How do I get access to blue light therapy?
Dermatology departments are not currently offering blue light therapy but a light emitting diode for home use is something that can be purchased. This is probably something best discussed with your dermatologist as it may not be appropriate for your skin condition.
Yours,
Sandy
Dr Sandy Flann, Consultant dermatologist
