Phototherapy uses lightwaves to treat certain skin conditions. The skin is exposed to an ultraviolet (UV) light for a set amount of time. Phototherapy uses a man-made source of UV light. UV light also comes from the sun. When combined with a medication called psoralen, the procedure is known as psoralen UVA (PUVA).

Possible Complications

The UV lights may negatively affect your skin in a number of ways, including:

  • Skin conditions could temporarily worsen
  • Itchy skin
  • Red skin due to exposure to the lights
  • Burning of the skin

PUVA treatment may also cause:

  • Nausea
  • Burning skin
  • Cataracts—lens of eye becomes cloudy, affecting vision
  • Headache
  • Fatigue

If you have received a great number of phototherapy treatments, you may be at risk for:

  • Premature aging of the skin, such as wrinkling and dryness
  • Age spots or freckles

Factors that may increase the risk of complications include:

  • Allergy to sunlight
  • Pregnancy or nursing
  • Medical conditions, such as skin cancer or systemic lupus erythematosus , that require you to avoid the sun
  • History of skin cancer
  • Liver disease—phototherapy may increase medication levels in the blood



This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.


American Academy of Dermatology 

National Psoriasis Foundation 


Eczema Canada 

Health Canada 


Gambichler T, Breuckmann F, Boms S, Altmeyer P, Kreuter A. Narrowband UVB phototherapy in skin conditions beyond psoriasis. J Am Acad Dermatol. 2005;52(4):660-670.

Muekusch G, Pitman J, Smiljanic D. Photoresponsive diseases. Dermatol Nurs. 2007;19(1):43-47.

Phototherapy. National Psoriasis Foundation website. Available at: Accessed November 9, 2015.

Phototherapy: UVB. American Osteopathic College of Dermatology website. Available at: Accessed November 9, 2015.

Psoriasis. EBSCO DynaMed Plus website. Available at: . Updated September 5, 2016. Accessed October 10, 2016

UVA photo(chemo) therapy. Derm Net AZ website. Available at: Updated November 10, 2014. Accessed November 9, 2015.

What happened to phototherapy? American Academy of Dermatology website. Available at: Accessed November 9, 2015.