Background
on Phototherapy
Sunlight has been known to have a beneficial effect on certain
skin disorders, in particular psoriasis, for many hundreds of
years. In the first decade of last century it was discovered that
the ultraviolet portion of sunlight was responsible for this effect.
Sunlight is a very unpredictable and unreliable source of ultraviolet
light and so artificial sources of this light began to be used
in treatment.
In the 1920's, a combination treatment of ultraviolet light and
application of a cream or lotion containing tar, was first introduced
and this remained a standard treatment for psoriasis and eczema
until the 1970's.
Over the past decade there has been renewed interest in phototherapy
due to the development of so-called narrowband UVB phototherapy.
The UVB spectrum contains forty different wavelengths and recently
it has been found that only a few of these are effective in treating
skin disease. thus with narrowband treatment, the light source
used only contains those effective wavelengths increasing the
specific response to treatment.
Let us now discuss a few of the details of the treatment:
Treatment
Prior to the first treatment, your response to UVB light is tested
by exposing small areas on your back to different doses. The result
is read 24 hours later. The initial exposure dose is small, and
hence the treatment is brief, but as your tolerance to the light
increases, the exposures are progressively increased. treatments
are given daily or three times each week in order to clear the
skin. Weekly or twice weekly treatment is usually required to
maintain a clear state.
Prior to each treatment you should apply a moisturizing cream,
such as Aquaphor or Eucerin, to the patches of psoriasis since
this will increase the effect of the light treatment.
Helpful Hints
• If your skin disorder involves the scalp you have to help
the light reach it. Short hair is obviously one answer. Hair bands
and bobby pins should be used to hold hair off the face and neck.
• Nail polish may be worn even if the fingernails and toe
nails are involved by your skin disorder. However, if the disorder
affects the skin under the nails, do not paint your nails.
• Scale on the skin tends to block UVB light from penetrating.
Try to remove as much scale as possible before each treatment
by soaking or applying an emollient.
• Regular, punctual treatment are the key to success with
phototherapy. Missed treatments simply delay a good response and
sometimes lead to failure of therapy. If you are having problems
keeping appointments, discuss the matter with the physician so
a fresh approach can be developed.
Phototherapy FAQ's
What is ultraviolet
light?
What types
of UVB light are available?
How does ultraviolet
light affect skin disorders?
Do
you need to be treated in the office?
What is ultraviolet
light?
Ultraviolet light consists of wavelengths of light found in sunlight
which are shorter than visible light. It is called ultraviolet
because it begins next to the violet end of visible light. Ultraviolet
rays cause sunburn and suntan. There are several types of ultraviolet
light and the one used in treatment is called UVB light.
UVB light is the portion of sunlight responsible for producing
a sunburn, a suntan, burning of the eyes, skin cancer and aging
changes in the skin. However, it is also the waveband that is
most effective in treating disease of the skin. In ultraviolet
phototherapy we aim to maximize the treatment benefits of the
UVB light and minimize the short and long-term problems that can
result from exposure to this light.
What types of UVB light are available?
High-intensity broadband UVB treatment has been used for many
decades and is effective in treating psoriasis and eczema. Narrow-band
UVB treatment is a recent development and is more effective in
many patients. The choice of treatment is individualized to the
patient and disease being treated.
How does ultraviolet light affect skin
disorders?
Recently there has been much research into how ultraviolet light
produces a beneficial effect and there appear to be three mechanisms:
• Ultraviolet light slows down the multiplication of skin
cells by suppressing formation of DNA in cells. This may explain
some of its effect in psoriasis, a condition in which cells are
multiplying too rapidly.
• Ultraviolet light alters the function of immune cells in
the skin but in doing so does not appear to affect our normal
immunity. This is probably the mechanism whereby ultraviolet light
helps some types of eczema and also possibly psoriasis.
• Ultraviolet light causes darkening and thickening of skin
so that less light can enter the skin. Disorders in which the
skin is more sensitive to light than is normal are probably helped
via this mechanism.
Do You Need to be Treated in the Office?
UVB light is present in sunlight and is emitted by sunlamp bulbs
used at home and in suntan parlors. A reasonable question is why
be treated in a doctor’s office? The answer is very simple:
You are more likely to get better.
Sunlight certainly improves some skin disorders but it seldom
clears them completely. Actually, it is probably not just sunlight
that is beneficial but the relaxation and enjoyment that is associated
plays a significant role. Sunlight of course, is not available
to us on a regular year-round basis and that is a limiting factor.
Sunlamps used at home or in suntan parlors are not helpful for
treating skin disease because they emit light that does not clear
psoriasis or other conditions.
Treatment Problems
Short-Term Problems of Phototherapy:
Sunburn
Suntan
Dryness
Freckles
Eye Damage
Potential Long-Term Problems of Phototherapy:
Skin Cancer
Aging Changes
Short-Term Problems of the Treatment
The UVB portion of sunlight is responsible for most of the changes
we see in our skin after we have been sunbathing. Therefore, most
of the problems of UVB phototherapy are the same as those we experience
after exposure to sunlight.
Sunburn
UVB light will produce pinkness and redness of the skin. The doses
of light used for your treatment are selected with the aim of
producing some pinkness of the skin because such doses are most
effective in clearing your rash. We do not aim to produce redness
or blistering of the skin but occasionally that will occur due
to unexpected responses of the skin to UVB light. If you are red,
treatment will be suspended until the sunburn has cleared. If
you became red after the last treatment tell the nurse and your
dose of light will be modified.
Suntan
All people who are able to tan will do so as a result of exposure
to UVB light. Many people regard this as a bonus but some people
do not like to have a darker skin. The tan will fade over 4-6
weeks after treatment has stopped.
Dryness
UVB light does tend to dry the skin but this can be easily alleviated
by applying a moisturizing cream.
Freckles
These flat, brown spots occur in susceptible individuals just
as they do following exposure to sunlight.
Freckles do tend to fade once treatment has stopped but can be
reactivated by subsequent exposure to sunlight.
Eye Damage
UVB light can sunburn your eyes. This problem is completely preventable
by wearing UV-opaque goggles while in the light box. Eye protection
must be used during treatment.
Potential Long-Term Problems of the Treatment
Like the short-term problems, the potential long-term problems
are the same as those seen in response to sunlight:
Skin Cancer
UVB light produces skin cancer in laboratory animals and there
is much evidence that sunlight causes this problem in humans.
However, several large investigations have failed to find a link
between UVB phototherapy and skin cancer. Regardless of this comforting
finding we must assume that UVB phototherapy will add to the cumulative
effect of exposure to sunlight and all people should take precautions
to reduce risk of skin cancer:
• Avoid prolonged or excessive sunbathing unless it is a
prescribed part of maintenance treatment.
• Male patients should wear an athletic support during treatment
if their skin disorder does not involve the genital area because
skin in this area is very sensitive to ultraviolet light.
• If your skin disorder does not involve the face, apply
a sunscreen to this area before treatment because facial skin
already receives a heavy exposure to sunlight and it is unwise
to increase the exposure.
• Any new lump or bump on the skin should be brought to the
attention of the physician.
Aging Changes
UVB light in sunlight appears to be the main cause of premature
aging of the skin and again, while there is no proven link between
UVB phototherapy and these changes, we must assume there is a
risk.
The same precautions taken to avoid skin cancer apply equally
well to aging changes.
Skin Diseases
Responsive to Phototherapy
Psoriasis
Eczema
Vitiligo
Photodermatoses (sunlight sensitivity)
Mylogis Fungoides
Pruritus (itch) of any cause
Eosinophilic pustular folliculitis
Pityriasis lichenoides
Pityriasis rosea
Urticaria
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