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nb-UVB and PUVA Phototherapy

 San Diego UVB and PUVA Phototherapy Treatment

Ultraviolet light treatment uses a specific wavelength or spectrum of light to treat psoriasis, eczema, vitiligo and a variety of other skin conditions including a certain form of cutaneous lymphoma.  The spectra of ultraviolet light found to be useful for inflammatory skin conditions are ultraviolet A (UVA) and ultraviolet B (UVB).

What is narrow-band UVB and how is it different than sunbathing or going to a tanning salon?

Narrow-band UVB has a wavelength of 311 nm.  This specific segment of the ultraviolet spectrum has been shown to be the most effective component of natural sunlight for the treatment of psoriasis.  Use of this targeted approach also carries the lowest long-term risk of skin cancer development.  While controlled and limited exposure to the sun can be beneficial for certain skin conditions including psoriasis, sunlight contains ultraviolet A, B and C radiation that are all thought to increase the long-term risk of skin cancer.  Tanning beds typically administer a broad spectrum of UVB and UVA  light, posing a similar risk of skin cancer as sunlight.

How is phototherapy administered?

Phototherapy can be used alone or in combination with systemic medications or topical sensitizing agents that increase the effectiveness of the light.  The topical sensitizing agent for PUVA (Psoralen + UVA) is a medication called psoralen.  When administered locally, for example to treat chronic hand eczema, bath PUVA is the preferred method.  Bath PUVA involves soaking the affected areas in a dilute solution of psoralen, followed by exposure to UVA light.  The prescribed treatment for nb-UVB or UVA phototherapy is typically 3 times per week for 1-2 months or longer, depending on the treatment response.  The duration of each treatment varies from less than 1 minute to 10 minutes.  Period maintenance treatments may be recommended as a preventative measure and to keep the skin condition under control.

How do narrow-band UVB and PUVA phototherapy work?

The precise mechanisms of nb-UVB and PUVA phototherapy are not known.  The effects of ultraviolet light are to decrease the rate of cell turnover (particularly in psoriasis patients) and to decrease the activity of the immune system in the skin, reduce inflammation and resulting damage to the skin.  Narrow-band UVB is one of the safest effective treatments for widespread inflammatory skin diseases.  PUVA phototherapy is one of the most effective therapies for chronic, dyshidrotic eczema and psoriasis of the hands and feet.  2-3 months of PUVA therapy may induce a prolonged period of disease remission.  It is important not to apply sunscreen, moisturizer or any prescription topical medication on areas to be treated prior to treatment, as it will block the UV light.

Possible risks and complications with nb-UVB and PUVA phototherapy:

  • Treatment with nb-UVB or PUVA phototherapy can contribute to photo-aging of the skin.  Tanning or darkening of the skin may occur.
  • Studies show that nb-UVB treatments do not appear to increase the risk of skin cancer, though there is still a theoretical risk that nb-UVB may promote skin cancers long-term.  Long-term therapy with PUVA (longer than 1 year of therapy) can increase the future risk of skin cancer, including melanoma.
  • Your doctor will start you at a low UV dose for the first treatment, then gradually increase the UV dose to minimize the risk of sunburn.  A sunburn reaction, blistering and scarring are possible complications.
  • Direct exposure of the eyes to UV light can increase risk of cataracts.  UV-protective glasses are worn during each treatment session to minimize this risk.
  • To further decrease the risk of sunburn, it is important to be consistent in exposing the same skin area(s) with each treatment.  Previously unexposed skin is at very high risk of sunburn if you have already undergone several phototherapy treatments.
  • A mild degree of redness in the skin as well as temporary itching may occur following treatments with nb-UVB and PUVA phototherapy.
  • Following treatment with PUVA phototherapy, it is important to avoid direct sun exposure for 8 hours to minimize the risk of severe sunburn.  Other than general sun protection measures, there are no special after-care instructions for nb-UVB treatments.

Please consult with your dermatologist to determine whether phototherapy would be an appropriate treatment option for your particular skin condition.