Philippa Willitts finds out how light therapy can be used to treat various skin, mood and sleep-related conditions…
Light helps us to see, enables plants to produce energy and allows our bodies to produce vitamin D. The therapeutic power of light is also increasingly being studied and used to manage conditions as varied as eczema, depression and neonatal jaundice.
Light therapy, also known as phototherapy, encompasses a range of different treatments and approaches – from increased exposure to sunlight, to specialist light-producing equipment. While some forms of light therapy have proved to be effective under research conditions, others are more experimental or controversial in medical circles. For this reason, if you are considering using light therapy it is important to understand exactly what you are embarking on. Anecdotal evidence can be powerful and persuasive, but it’s vital to be aware of the potential risks and limitations associated with untested treatments.
Light versus bright
Light therapy for skin conditions uses ultraviolet light, which is made up of UVA (400-320 nanometer) and UVB (320-290nm) wavelengths. UVA light on its own is generally ineffective, but when combined with a chemical – typically administered orally – the skin will be more responsive to it. UVB light is employed in two forms – broad-spectrum UVB, which uses the full spectrum of radiation, and narrow-band UVB, which is becoming increasingly popular as it omits some of the more damaging aspects of UVB light, allowing it to be used in more intensive treatments.
Some people favour using commercial sunbeds as a form of ‘DIY light therapy’, but The Psoriasis Association warns against this. The levels of exposure in the UVA light emitted by sunbeds are impossible to monitor, which means safety guidelines can’t be applied. Given that sunbeds can increase the risk of malignant melanoma by as much as 59%, sunbeds are not only an ineffective form of light therapy, they can actually cause more problems than they cure.
Light therapy used to treat mood and sleep disorders is more accurately known as ‘bright light therapy’. Bright light therapy is delivered via a light box, which shines intense light for a set period of time. The user sits close to the illuminated light box and can get on with various daily tasks, such as reading, eating or working, for periods of between 15 minutes to several hours; there is no need to look directly into the light.
The illumination emitted from light boxes of this type can be between five and 20 times higher than normal lightbulbs, though they tend to filter out UV light, so to avoid damage to the skin and eyes – whereas it’s precisely this latter aspect that light treatments for skin conditions rely on for their effectiveness.
For people with psoriasis, targeted light therapy – where useful ultraviolet rays are isolated and aimed directly at problematic skin areas – is a safer approach than sun seeking, and can encourage changes in the skin that improve the person’s symptoms, slowing down the multiplication of skin cells responsible for the dry, red patches of skin that are typical of the condition.
For acne, studies have thus far failed to conclusively prove that light therapy is beneficial. It does seem to help the skin in the short term, but there as yet insufficient evidence from long-term research or people with severe acne to recommend light therapy at this stage.
Vitiligo, on the other hand – where pale patches form in the skin – has been shown in various studies to react well to light therapy, as it helps to add pigmentation to the affected areas.
Seasonal affective disorder (SAD), also known as winter depression, is a debilitating condition whereby a lack of natural daylight can lead to low moods, tearfulness, increased stress and feelings of irritability or even despair. SAD can also cause other symptoms, such as fatigue, an inability to concentrate and increased appetite.
Bright light therapy has been found to be effective for winter depression in a range of clinical trials. Using a light box for 20-30 minutes each morning for two weeks has been shown to improve the symptoms of SAD, apparently proving to be not just as effective as anti-depressants, but also demonstrating more rapid results, with positive effects apparent after just one week’s use.
What are the downsides?
Bright light therapy can also help people with a variety of sleep problems. Poor sleep hygiene, lying in at the weekend, international travel and lack of regular exercise can all have an impact on sleep patterns and cause insomnia or sleep phase disorders. The resulting tiredness can then affect people’s work and personal lives and even present potential hazards, such as dangerous driving.
Morning bright light therapy sessions are thought to improve wakefulness and boost energy, while using a light box in the evening can help people overcome problems with early tiredness. It can help to reinforce the body’s natural 24-hour sleep cycle, and is thus an obvious choice for conditions such as delayed sleep phase disorder – where individuals are unable to fall asleep until the early hours of the morning – and people who work shifts, who may need to switch in and out of different sleep cycles on a regular basis.
Both light therapy and bright light therapy are generally thought of as very safe treatments. However, there have been some reports of side effects. When undergoing light therapy for skin conditions, some patients may experience sickness, red or irritated skin and cold sores. Those receiving courses of bright light therapy may sometimes experience symptoms such as headache, eye strain, restlessness and nausea, though these usually pass after a few days. People with bipolar disorder, particularly those prone to manic periods in spring or summer, should be carefully supervised to as to avoid the risk of the light provoking a manic episode.
Some drugs and herbal supplements, such as St John’s Wort or chlorpromazine, can increase photosensitivity, so light boxes should be used with caution when these are taken. No particular risks have been found with using light therapy during pregnancy, but given that proper testing has yet to be carried out in this area, it is advisable for pregnant women speak to their doctor before considering such treatments. People with eye problems, such as cataracts or glaucoma, are also advised to seek advice before using this treatment.
How to get light therapy
GPs can refer patients with certain skin conditions to an NHS dermatologist to receive light therapy in a hospital setting. Treatments of this kind are rarely carried out at home for safety reasons.
For bright light therapy, light boxes can be bought from as little as £40, rising to £700-800 for more advanced models. Light boxes are not available on the NHS, but can occasionally be loaned from specialist SAD clinics.
The Seasonal Affective Disorder Association
The charity offers Guidelines document containing information on how to choose a light box that is both safe and effective – further details are available at www.sada.org.uk/lightboxes or by emailing email@example.com
The Psoriasis Association
08456 760 076 www.psoriasis-association.org.uk
A compact SAD lightbox that can be situated on a desk at home or in the workplace, the Brightspark gives out 10,000 lux at 2cm, weighs just under two kilograms and comes with a three-year guarantee.
Recently unveiled by Philips is this wearable light therapy device, which is designed to help manage the symptoms of mild to moderate psoriasis vulgaris with the aid of non-UV light emitted by 40 high intensity blue LEDs.
Among the smallest 10,000 lux lightboxes on the market, the 1.5kg Litepod can be optionally purchased with an accompanying Travel Bag and is able to provide a course of SAD light treatment within 45 minutes to an hour.