The roots of phototherapy can be traced back to ancient folk medicine which followed sun worship as an important part of natural healing. The oldest documentation of light therapy is in 1500 BC where Indian medical practitioners used seeds and leaves of the Bavachee or Vasuchika plant on non-pigmented areas of the skin, followed by an exposure to the sun light. These plants contained photosensitizing elements that helped cleared psoriasis. Similarly, phototherapy has also been documented in the 10th century in China in curing various skin ailments.
Principle behind Light Therapy
Phototherapy is based on the principle that light is a powerful drug. It can affect animal vision, plant growth, circadian rhythms and cause sunburns. Today, we know that prolonged exposure to harmful UV rays from the sun can lead to various skin diseases including skin cancer. Phototherapy, or light therapy, however, seeks to use light to cure diseases while minimizing the adverse reactions of the skin to light.
This form of ‘controlled’ phototherapy was first used by Niels Finsen at the beginning of the 20th century (and hence he is rightfully known as the Father of Modern Phototherapy). Finsen utilized natural sunlight and carbon arc UV radiation to cure cutaneous Tuberculosis. Today, nearly 100 years after this primitive form of light therapy, doctors make use of modern light equipment for prophylactic and therapeutic purposes.
To use photo-medicine properly, a great deal of experience in handling optical radiation is necessary. Light therapy uses infrared, visible as well as ultraviolet light and its aim must be to maximize the benefits of light while lowering its risks. Hence correct dosage along with supervision by a trained doctor is of utmost importance when using phototherapy.
Diseases and Phototherapy
- Psoriasis and vitiligo are two common skin disorders that are successfully treated with phototherapy. Acne vulgaris is another common skin condition affecting adults and teenagers that can be successfully treated with light therapy using the UVA, UVB as well as the visible radiation light in blue and green wavelength range (or filtered metal iodide lamps doped with gallium).
- The visible range of optical radiation is also used for preventing many psychological conditions. SAD or seasonal affective depression in winters, as well as jetlag and the “shift-worker syndrome” can all be successfully prevented using light therapy. In such forms of therapy, bright light from fluorescent lamps is used to regulate the hormone melatonin. This is the hormone needed to moderate the effects of shortening winter days on sleep and mood, disruption of which can lead to winter time depression in individuals typically residing in the Northwestern countries.
- Photodynamic therapy using red light is also used for treating skin pre-cancer as well as certain superficial forms of skin cancer.
- Hyperbilirubinemia (neonatal jaundice) is treated effectively using a form of visible phototherapy that uses blue light of wavelength 400 to 500nm.
- Physiotherapists often use phototherapy for preventive as well as rehabilitation purposes.
Side effects of certain types of phototherapy
There are a few short term side effects of using the UVA or PUVA based light therapy. In case of treating psoriasis, the UVA light therapy can cause short term headaches, dizziness, and nausea. Long term side effects of using PUVA for psoriasis include permanent skin damage following sun exposure, cataracts (which can be prevented by using safety goggles) and weakened immune system.
Chronic UV exposure can also lead to permanent skin damage such as wrinkles, age spots and other forms of aging.
Tanning beds that are an alternative to natural sunlight also emit harmful UVA radiation and have now been proven to cause premature aging as well as increased risk of skin cancer.
Phototherapy or light therapy involves the exposure of the skin to ultraviolet light on a regular basis. When done right and at a proper medical facility under the supervision of an experienced practitioner, light therapy can be very effective in treating various skin conditions as well as psychological disorders.