phototherapy

medicine

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July 1, 2026

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Phototherapy is a medical treatment that uses light to manage diseases. Danish physician Niels Ryberg Finsen pioneered this field, earning the 1903 Nobel Prize for his work in treating skin diseases with light.1

One application is treating newborn jaundice by exposing infants to intense visible light, specifically wavelengths between 420–480 nanometres, which helps detoxify and eliminate bilirubin. Photodynamic therapy (PDT) is another form, where a light-absorbing substance is administered to tumor cells, which are then destroyed by targeted light exposure, often from lasers. Additionally, ultraviolet radiation is used in some dermatitis treatments to suppress immune reactions.234

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radiation
Phototherapy
Intense visible light is used in treating newborns’ jaundice, a disease characterized by the accumulation of the pigment bilirubin in the bloodstream during the first few days of life. Since wavelengths of 420–480 nanometres absorbed in the skin expedite detoxification and elimination of the…
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Intense visible light is used in treating newborns’ jaundice, a disease characterized by the accumulation of the pigment bilirubin in the bloodstream during the first few days of life. Since wavelengths of 420–480 nanometres absorbed in the skin expedite detoxification and elimination of the…
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Niels Ryberg Finsen
…and the founder of modern phototherapy (the treatment of disease by the influence of light). He received the 1903 Nobel Prize for Physiology or Medicine for the application of light in the treatment of skin diseases.
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…and the founder of modern phototherapy (the treatment of disease by the influence of light). He received the 1903 Nobel Prize for Physiology or Medicine for the application of light in the treatment of skin diseases.
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psoriasis
…can also be treated with phototherapy, in which the skin is exposed to ultraviolet light. While phototherapy can be highly effective, it does have side effects, including pain, irregular pigmentation, and scarring. In addition, long-term treatments are associated with an increased risk of skin cancer.
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…can also be treated with phototherapy, in which the skin is exposed to ultraviolet light. While phototherapy can be highly effective, it does have side effects, including pain, irregular pigmentation, and scarring. In addition, long-term treatments are associated with an increased risk of skin cancer.
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