How Long Does it Take for Phototherapy to Work?

phototherapy lamp dermahealer

Phototherapy, also known as light therapy, is the use of UV light to treat skin conditions and other diseases. It has been used worldwide for nearly a century to treat chronic skin problems such as eczema, psoriasis, and vitiligo. 

UV light can be used to decrease the local immune system in the skin. In conditions such as psoriasis, phototherapy can also slow down the development of thick, scaly skin. 

UV light therapy is used in vitiligo for its additional ability to stimulate melanocytes, the skin's pigment-producing cells. This makes phototherapy a nice treatment option for just about anyone, especially those who don't like creams, those who prefer a natural and steroid-free treatment, and those who want additional control using a combination of therapies. Phototherapy is also a good option to consider for children and women during pregnancy.


How Does Phototherapy Work?

Phototherapy uses UV light, which is also found in sunlight. UV light therapy can also be used in combination with other medications applied on the skin. 

Phototherapy can be given to a specific area of your body or to your entire body if more than 5% of your skin is affected.

There are 2 main types of light therapy:

  • Ultraviolet B (UVB)
    • This is further classified into two types: broadband and narrowband (NB-UVB). The difference is that NB-UVB gives off a shorter wavelength of UV light. 
  • Psoralen-UV-A (PUVA)
    • This type of therapy uses UVA light and medication taken by mouth called psoralen that makes your skin more sensitive to light.


How Long Does it Take for Phototherapy to work?

Most people see results within 24 to 36 treatments, although some people respond to light therapy more slowly and changes are seen after as many as 72 treatments. Generally, patients see an average of 50% to 70% re-pigmentation of affected skin after 6 to 12 months of treatment. Areas with hair follicles, including the face, chest, upper arms, back, buttocks, and upper legs re-pigment the fastest and with the best results. 

The wrists, hands, ankles, and feet are the slowest to respond. Re-pigmentation may be more challenging when white hairs are visible because the originating pigment-producing cells may be found in the follicle.


Cancers and Pre-cancers

A type of phototherapy known as photodynamic therapy is used to treat some kinds of cancer and pre-cancers. It involves the use of a drug called a photosensitizer.

Photosensitizers are applied to the skin. When light strikes the skin, it interacts with the drug to make a kind of oxygen that kills nearby cancer cells.

Photodynamic therapy is used to treat conditions such as:

  • Barrett's Esophagus - a precancerous condition often caused by acid reflux
  • Cancer of the Esophagus 
  • Endobronchial Cancer - a type of lung cancer

Photodynamic therapy is sometimes called photo-radiation therapy or photo-chemotherapy.

Phototherapy has some advantages over treatments like radiation and chemotherapy. For example, it doesn’t usually have any long-term side effects. It leaves less scarring than surgery. And phototherapy costs a lot less than the other treatment options for cancer.

The downside is that it usually only works in areas on or just under the skin, where light can reach. It also does not help much with cancers that have spread.