Pros and cons of phototherapy

| Sarah L. Stewart

Most new moms and dads face unpleasant sleepless nights, but for the parents of Melissa Leeolou, those nights were unbearable.

The young woman from Long Island, New York, was just a year old when she was diagnosed with psoriasis. By age 3, the redness and plaques covered 80 percent of her small body, and her parents would cover her hands with gloves at bedtime to dull the damage caused by scratching. Still, she would scratch until her skin bled.

“I’d be crying all night because of the pain,” Leeolou says. “It was very difficult to treat when I was a child because my parents did not feel comfortable with biologic medications.”

Biologics had not yet been approved for children, and topical treatments had little effect. Desperate for relief, the family poured their life savings into a month-long sojourn for the 3-year-old to the Dead Sea, known for the healing effects of its mineral-laden water. By the time they returned home, Leeolou’s skin had almost completely cleared, and it stayed that way for a year. But soothing water wasn’t the only therapeutic benefit the family discovered beneath the bright sunshine of the Israeli desert.

“That was my first introduction [to light therapy],” says Leeolou, a former professional ballerina who is now applying to medical school. “After that, we always prioritized getting sun exposure.”

Melissa Leeolou

Like Leeolou, many people with psoriasis discover on their own the remarkable effect ultraviolet (UV) rays can have on the disease. But they also know the downsides of getting too much sun, from premature aging to skin cancer.

For many patients, the solution is phototherapy. Regular, medically supervised exposure to UV light — which provides the benefits of sunbathing while minimizing its risks — can serve as a powerful tool in the treatment of psoriasis.

“The majority of patients are good candidates for it,” says Joel Gelfand, M.D., director of the Psoriasis and Phototherapy Treatment Center at the University of Pennsylvania. “When patients are selected and treated properly, they usually do very well.”

Leeolou, now 26, started phototherapy when she was about 14. Throughout high school, regular light treatment halved the percentage of her skin covered in plaques.

“It did not cure my psoriasis, but it alleviated a lot of the pain, a lot of the redness, and it did minimize the thickness of my plaques and how much of my body was covered,” Leeolou says. “It did provide a lot of relief.”

Reaping the benefits

In 2012, Gelfand and several co-researchers conducted a survey of 1,000 dermatologists nationwide to learn their preferences for treating moderate to severe psoriasis. Researchers found that ultraviolet B (UVB) phototherapy was the most commonly favored first-line intervention for healthy adults, recommended for about half of such patients. 

Safety is a big reason many doctors prefer this time-tested treatment, even in the age of revolutionary psoriasis drugs.

“Light therapy is considered to be the safest way to treat psoriasis because you’re treating from the outside in,” Gelfand says. While biologics can increase the chance of infections and require monitoring for other adverse effects, the risks associated with phototherapy are fairly minor, ranging from nausea to the possibility of sunburn on freshly exposed skin.

“We’re using the wavelengths that are the most effective and least detrimental,” says Jerry Bagel, M.D., director of the Psoriasis Treatment Center of Central New Jersey. “This is not the kind of light you get in a tanning salon.”

Wavelengths on the UV light spectrum are measured in nanometers, or billionths of a meter. UVA light (the type generally used in tanning beds and most closely associated with skin aging and melanoma) spans from 320 to 400 nanometers. UVB light ranges from 280 to 320 nanometers, with the window from 311 to 313 nanometers — called narrowband UVB — the most common for treating psoriasis. Narrowband UVB replaced broadband UVB, as it was found to be the most effective wavelength to treat psoriasis without causing sunburn.

For each phototherapy treatment, patients typically step into a light box at a dermatologist’s office nude (although men must cover the genital area, and most people wear goggles, plus a towel over the eyes and face). Bulbs emit a short burst of narrowband UVB light, ranging from a few seconds to a few minutes, depending on the person’s skin type and how many treatments he or she has had. The rays penetrate bared skin, slowing the growth of affected skin cells and decreasing inflammation. And it’s remarkably effective in doing so: People with psoriasis who receive light therapy three times per week for 12 weeks have a 75 percent chance of clearing the skin by 90 percent for six months or longer, says Bagel, a member of NPF's Medical Board.

“It’s a very valuable therapeutic method for people with psoriasis, especially because it’s very safe,” he says.

The combination of safety and efficacy makes phototherapy particularly appealing to patients who aren’t good candidates for biologics because of age, pregnancy or other medical conditions.

“It’s so comforting having a treatment option that doesn’t have internal side effects,” Leeolou says.

Assessing the limitations

For much of her adult life, Nancy Renner’s silver hair hung below her ribs, making a ponytail as thick as her wrist. Then her psoriasis flared in 2015, and she says the disease morphed from a nickel-sized lesion on her head to an excruciating inflammation that covered about a third of her body. The lesions ravaged her scalp, causing so much hair to fall out that her ponytail was reduced to the size of her pinky. Renner noticed improvement elsewhere on her body during a sunny vacation, but beneath her thinning hair, the skin remained broken and bloodied.

“My scalp just did not heal,” says Renner, a 67-year-old former school counselor in Cottage Grove, Oregon. So when a dermatologist suggested phototherapy, Renner made a difficult choice: She decided to shave her head so the UV rays could reach her scalp.

“I went to my son’s house and said, ‘I need you to take my hair off,’” Renner recalls. “I was careful not to look at myself in the mirror.”

After just 10 days and a few light treatments, her wounded scalp had healed of all lesions. Nearly a year later, Renner has a healthy head of short hair and her skin remains free of psoriasis — a transformation she attributes only partly to phototherapy, and largely to changes in her diet, exercise habits and stress management.

“The light therapy was fabulous to give me comfort,” she says. “It diminished the symptoms while the inside of my body healed.”

Nancy Renner

As encouraging as it is, Renner’s success story underlines one of the drawbacks of light therapy: Its effectiveness is limited to areas of the body where the rays can shine. Though handheld units can help access hard-to-reach areas, psoriasis of the scalp, genitals and nails generally don’t respond well to traditional UV treatment, experts say. Furthermore, phototherapy doesn’t treat psoriatic arthritis, which affects about a third of people with psoriasis.

Another disadvantage is inconvenience. Although office visits for light therapy typically last just 15 minutes from start to finish, the necessary frequency of treatment can be a burden. “It’s obviously cumbersome to come into the office three times per week,” Bagel says. “But if you’re only coming in twice a week, it’s not going to work.” 

The strain can be especially great for rural patients like Renner, who for months drove 60 miles round trip to Eugene, Oregon, for each session. Additionally, some insurance plans require a separate copay for each visit. 

“From a patient perspective, it can get quite costly,” Bagel says.
And although phototherapy is considered the safest treatment for psoriasis, even narrowband UVB isn’t without risk of skin damage. “There really haven’t been definitive studies to rule that out,” Gelfand says, although he adds that after decades of clinical use, such side effects have not been observed. “If it does increase [skin cancer risk], it’s probably modest enough that it’s not a major concern.” 

Lighting the future 

Narrowband UVB emitted from a light box may be the most common type of phototherapy for psoriasis, but it isn’t the only kind — and innovations continue to expand the options. Excimer laser treatments, which target localized psoriasis lesions with doses of narrowband UVB, can be especially helpful for hard-to-reach places. For instance, this therapy can treat the scalp without having to trim back hair. Additionally, some patients still benefit from PUVA, a less common treatment dating to the 1970s that combines exposure to UVA rays with a pill, psoralen, that causes the skin to become more sensitive to light. The skin damage associated with UVA, however, limits the recommended duration of this treatment.

“You can treat the psoriasis with really high doses of UV light,” Gelfand says. “You don’t have to treat the entire body.”

Home-based narrowband UVB units have also become safer and easier to use, says Gelfand, who is conducting a study comparing the effectiveness of office-based versus home-based phototherapy. Prior research shows that 82 percent of people with psoriasis would prefer home-based treatment if it proved equally effective. 

“The overarching goal is to make research and treatment more patient-centered,” Gelfand says.

After relying on phototherapy for the majority of her youth, as an adult, Leeolou eventually turned to biologics. But when her mother suddenly developed psoriasis a decade ago, she followed her daughter’s lead and first tried several months of phototherapy — and the disease has been in remission ever since.

“That’s all she really needed,” Leeolou says. “It’s great to have phototherapy as a first-line intervention.”

And then there was LITE

In 2017, the Patient-Centered Outcomes Research Institute awarded an $8.6 million contract to Joel Gelfand, M.D., for a clinical trial called LITE, to be conducted in partnership with NPF. LITE’s purpose: To study the effectiveness and safety of 12 weeks of home-based versus office-based phototherapy for the treatment of psoriasis. Gelfand and his team are also studying whether patients with fairer skin are more prone to problems with tolerability, such as burns from increased light penetration, and whether those with darker skin are more prone to problems with effectiveness due to decreased ultraviolet light penetration. 

LITE, which launched in 2019, involves a controlled study of patients age 12 and older under real-world conditions – either at home or at their health care provider’s office. LITE could someday provide the data necessary to better inform treatment decisions for hundreds of thousands of phototherapy candidates.

LITE is not scheduled to end until 2023. We are still recruiting sites and patients. If you are a provider or clinician and you offer narrowband UVB phototherapy, we invite you to join LITE.

Editor's note: The section above has been updated to reflect that the LITE study has launched and is underway.

Learn more about phototherapy – or other treatment options

NPF Patient Navigators can answer your questions and share information about psoriatic disease treatments. Through our resources and one-on-one support, we help you live your healthiest life with psoriasis or psoriatic arthritis.

Driving discovery, creating community

For more than 50 years, we’ve been driving efforts to cure psoriatic disease and improve the lives of those affected. But there’s still plenty to do! Learn how you can help our advocacy team shape the laws and policies that affect people with psoriasis and psoriatic arthritis – in your state and across the country. Help us raise funds to support research by joining Team NPF, where you can walk, run, cycle, play bingo or create your own fundraising event. If you or someone you love needs free, personalized support for living a healthier life with psoriatic disease, contact our Patient Navigation Center. And keep the National Psoriasis Foundation going strong by making a donation today. Together, we will find a cure.

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