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What Is Phototherapy and Can It Treat Depression? (Most Likely, Yes)

Phototherapy — or light therapy — applies artificial light to treat concerns like eczema, psoriasis, jaundice, and even depression. Is phototherapy safe? Can it be used at home? Dr. Holly Singletary has the answers.

Interview has been edited for clarity.

What is phototherapy, and how does it work?

Phototherapy, also known as light therapy, is essentially using light for a therapeutic effect.

It’s been used worldwide in many fields of medicine, including dermatology and neonatology. In dermatology specifically, phototherapy is useful because it directs wavelengths of light in specific doses to help patients with various skin concerns.

Phototherapy quote

Light therapy for skin concerns

Phototherapy is used for dermatological conditions such as psoriasis, eczema, vitiligo, certain cutaneous lymphomas, sclerosing disorders, and even chronic itching, to name a few.  

Per Dr. Singletary, “For patients with limited skin concerns — for example, only affecting the knees — we may suggest applying topical creams directly to the affected areas.” 

“If skin conditions spread, it's more laborious to put multiple different creams all over the body, once or even twice a day,” she adds. 

When skin diseases are moderate or more widespread, doctors will often consider systemic medications, such as an oral pill or injectable. 

Light therapy

As with any medication, Dr. Singletary notes the need to consider potential side effects. “While potential side effects have to be considered with phototherapy as well, we might choose phototherapy as an option prior to moving toward some systemic therapies.” 

Phototherapy can be also added for patients who are on other medications but are not getting the desired response. Phototherapy can help these individuals lower their dose of systemic medications. 

“Many patients also want a steroid-free option,” says Dr. Singletary. “This is another area where phototherapy can play a valuable role.” 

Phototherapy types

Phototherapy in dermatology is available in several subtypes. According to Dr. Singletary, the phototherapy prescribed by dermatologists includes UVB, PUVA (also called photochemotherapy), and UVA-1.

“UVB is probably the one that we use most commonly in dermatology for skin conditions like psoriasis and eczema,” explains Dr. Singletary. “There are two types of UVB — broadband and narrowband. Narrowband means the spectrum being exposed to the skin filters everything other than the short span of wavelength, the 311- to 313-nanometer range, which has proven effective for skin conditions.” 

Exposing the skin to the most effective wavelength can minimize potential side effects from ultraviolet radiation. The Excimer laser emits a high-intensity narrowband UVB wavelength and has been approved for the treatment of chronic and localized psoriasis.

Many professional organizations such as the American Academy of Dermatology (AAD), the Centers for Disease Control and Prevention (CDC), the US Food and Drug Administration (FDA), and The National Psoriasis Foundation do not recommend tanning beds to treat skin conditions.

PUVA, also called photochemotherapy, is another form of light therapy that can be prescribed, says Dr. Singletary. “Patients can either prep their skin in a medicated bath, apply a cream or gel, or even take an oral medication called psoralen, all of which enhance the effects of the light therapy.” 

What about additional light sources like sunlight and tanning beds? “We know that UVB works best for psoriasis, and although sunlight has both UVB and UVA, we don't typically recommend sunlight as a treatment option. Many factors come into play when being in the sun, such as cloud cover, the location, different genetic characteristics that determine someone’s sensitivity to the sun, medications they might be taking that worsen sensitivity, and so on.”  

Check out Dr. Singletary’s top sun tanning tips for more info on sun-exposure safety. 

Some people visit tanning beds at commercial salons as an alternative to help treat their skin conditions. 

“Tanning beds emit mostly UVA rays. Ultraviolet radiation, particularly from these devices, can damage the skin, cause premature aging, and increase the risk of skin cancer. Many professional organizations such as the American Academy of Dermatology (AAD), the Centers for Disease Control and Prevention (CDC), the US Food and Drug Administration (FDA), and The National Psoriasis Foundation do not recommend tanning beds to treat skin conditions.”

Exposure using these sources is unpredictable; without a focused and effective wavelength, the doses and timing can’t be managed appropriately. 

Options for at-home phototherapy

Some people prefer to get phototherapy treatments in the privacy of their homes.

woman taking light therapy at home

Most patients who are prescribed phototherapy will start the treatment at their physician’s office and be monitored.

“Once stable and maintenance therapy begins, home units can be convenient and economical for patients. Physicians will recommend the best type of device for the patient, such as a panel, a held wand, or a small box, depending on the size of the affected area.” 

Regular follow-ups are still important to monitor progress.

Is phototherapy safe for pregnant people and children?

According to Dr. Singletary, narrowband UVB phototherapy is a valid option for pregnant people and children with moderate to severe skin concerns.

Does phototherapy work for depression?

“Although this is not my area of expertise, studies have shown that light therapy can alleviate depression, particularly seasonal affective disorder,” says Dr. Singletary. “It has also been used to relieve jet lag, certain sleep disorders, and even dementia, but additional research is needed to determine its usefulness in these areas.”