Phototherapy simply means treatment with light. For treating skin disease, Narrowband ultraviolet B (UVB) light is the most common type of phototherapy. This uses a special machine to emit UVB light at 311-312 nm, which is the most beneficial portion of natural sunlight for skin diseases. Importantly, it also avoids the UVA aspect of sunlight which is very damaging to skin, and can accelerate aging and progression towards skin cancers.

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Broadband UVB phototherapy (290-320 nm), PUVA (Psorlaen and UVA), and UVA1 (340-400 nm) are other forms of phototherapy that are used less frequently in treating eczemas, but may be used in certain circumstances.

Phototherapy appears to work in several ways:

  • It directly reduces itch
  • It has an anti-inflammatory effect
  • It increases vitamin D production
  • It appears to help increase bacteria-fighting systems in the skin


While it is very safe and is arguably safer than even natural sunlight due to it’s more specific and controlled nature, it still can cause burns, increased aging, and increased risk of skin cancers over time.

When is Phototherapy Used?

Phototherapy is used for widespread eczema or for localized eczema (such as hands and feet) that has not responded sufficient to topical treatments. For some, it can be a way to avoid using more powerful systemic treatment such as cyclosporine or methotrexate.

Does Phototherapy work?

Yes, it seems to help about 60-70% of patients with eczema that have not responded adequately to topical treatments, though it does not work for everyone. When it does work, it is not a rapid improvement like some treatments: generally 1-2 months of steady treatment is necessary to start to see improvement. Fortunately for many patients, when it does work it seems to be a “remittive” therapy, meaning it can put the eczema in a quiet state for a longer period of time, sometimes even long past the phototherapy has ended.

What are the downsides to Phototherapy?

There are several issues with phototherapy that must be considered before starting treatment:

  • Cost: although generally covered by most insurance plans, some plans do not cover it at all. Others may cover it, but there may be an expensive co-payment due at the time of each treatment, which can get very expensive
  • Time: for it to be effective, phototherapy generally requires 2-3 treatments per week in the office. Work and school schedules must be considered along with travel time, parking, and the treatment time. For some, this is just not possible, especially given the relatively slow onset of improvement (1-2 months to see improvement, generally)
  • Risks: burns, increased aging, and increased risk of skin cancer over time are all significant risks with any type of phototherapy. Eye protection must be worn for every treatment to prevent damage to the eyes.


What should I expect with Phototherapy?

  • During your visit you will apply a moisturizing oil to the skin and stand in the cabinet undressed except for underwear and protective goggles
  • The machine will be activated for a short time, usually just seconds to minutes, and will treat the entire body, or just certain exposed areas
  • Careful records are kept of your response and the light is slowly increased with each treatment
  • After several months of treatment, the frequency of the visits can sometimes be reduced to once or twice weekly
  • If things continue to improve, phototherapy can be stopped for a period to see if the eczema is in remission
  • If successful, some patients may restart the cycle or simply come once or twice weekly to maintain their improvement