Phototherapy belongs together with heliotherapy (Helios, gr. = Sun) to the medical treatments with light. Phototherapy works with artificial light sources such as UV or white light lamps. Heliotherapy, on the other hand, uses natural sunlight.
Fields of application of phototherapy
The following phototherapeutic fields of application are distinguished:
- Infrared light: heat radiation in the case of rheumatic diseases or chronic inflammations (eg paranasal sinuses)
- White light: Irradiation of sleep disorders and winter depression
- UV radiation: skin diseases (atopic dermatitis, psoriasis, acne), jaundice in newborns.
A phototherapy in the broadest sense is also the use of lasers, which has been introduced in many areas of medicine in recent years (for example, in surgery, ophthalmology, cancer therapy, cosmetic treatments).
The effects of different forms of light on the body are very different. Above all, the infrared light has a warming effect. It increases blood circulation, has muscle relaxing and relieves pain.
The UV light has a special effect on the skin. Irradiation can calm the immune system in the upper layers of the skin. This is important in allergic diseases such as atopic dermatitis, as they are based on an overactive immune system.
Even inflammatory skin diseases can be alleviated. In psoriasis, the radiation has a growth-inhibiting effect and can thus stop the increased formation and desquamation of the skin cells.
In paediatrics, UV light is used to treat jaundice in newborns. This yellowing of the skin is due to the incorporation of a degradation product of the red blood pigment hemoglobin, which can be excreted via the kidney only in small amounts. Due to the UV irradiation, the dye breaks down into readily soluble components that can be excreted via the urine.
The irradiation with white, bright light, which corresponds approximately to the composition of sunlight, is used primarily in the therapy of sleep disorders. This method is commonly referred to as light therapy.
Sleep disorders are often based on shifts in the biological daily rhythm (eg shift work). Irradiation in front of a screen ("light shower") can bring the organism back into line with the time of day. The screens are also used in the treatment of so-called winter depressions.
These mental disorders are triggered by a lack of sunlight, which leads to an imbalance of important messengers and hormones (melatonin, serotonin). In no case but include visits to commercial solariums. A light therapy with UV light must always be medically useful and monitored.