Psoriasis treatments: phototherapy (light therapy)

Phototherapy treatment uses ultraviolet light (UV) to slow down skin cell production. A course of treatment involves multiple sessions, takes place in a hospital and is managed by a dermatologist. It can be an effective treatment for some types of psoriasis that are too widespread for topical treatments alone.

Many of the young people we talked to had phototherapy. Some people had more than one course of phototherapy at different times, although there is a limit to how many courses a person can have without damaging their skin. Hannah heard that for her skin tone the limit was four courses. Adam worries about ‘using up’ treatment options for psoriasis and having none left to try. Ella and Lola had heard of phototherapy and thought they might consider it in the future.
Most of the people we talked to had UVB phototherapy (using ultraviolet B). Lucy and Zara had also tried PUVA phototherapy: when a treatment containing psoralens is put on the skin (or, sometimes, swallowed as a tablet) to make the skin more sensitive to light before exposure to ultraviolet A light. Lucy explains “you go in the bath first with a certain thing on that makes your skin more sensitive to the light and then go in [the light box]”. Zara remembers there were sometimes other dermatology patients in the room when she had the psoralen ‘gel’ applied to the psoriasis on her feet.

What’s it like having phototherapy?

Most people didn’t know what to expect when they first heard about phototherapy. Steven and Adam were nervous at first. Zara said having phototherapy doesn’t hurt or feel warm and it’s okay to move a bit rather than stay completely still. The ‘dose’ of phototherapy (number of seconds of ultraviolet light) is gradually increased over sessions. Megan had three weeks of phototherapy with a session every other day: starting at five seconds of UVB which increased by two seconds each time and then gradually back down to five seconds. Everyone wore protective eye glasses/goggles and underwear/a cloth to cover their genitals, as these areas of the body are very sensitive to ultraviolet light. Some people avoided using certain cosmetic or perfumed products on the days of their phototherapy sessions – Steven didn’t use aftershave or deodorant as he says it “burns off” in the treatment.
Some described the phototherapy room or ‘light box’ as looking a bit like a stand-up sunbed. Lucy had been to two hospitals for different courses of phototherapy and compared them: the most recent one had bigger phototherapy treatment rooms and a separate changing room. Adam, Zara, Abbie and Megan said the medical professionals they saw for phototherapy were friendly. Sometimes there were other people with psoriasis in the waiting room before they went in to the treatment room for their phototherapy. Zara had only seen adults, rather than other young people, at her dermatologist’s waiting room.
Most people went for phototherapy 2-3 times a week. The period over which they did this varied, from two and a half weeks to four months. This became tiring over time for some. Megan used public transport to get to and from her phototherapy sessions, which became “stressful” and “repetitive” with “long days”.
A practical issue is fitting phototherapy sessions around school and work. Although the actual treatment only took seconds/minutes, the trip to the hospital and wait could be time-consuming. Zara, Louie and Hannah missed out on classes. Damini timed her phototherapy to start in the summer holidays so she didn’t need time off school. Louie’s parents work full-time which made it tricky taking him to each appointment, so his grandparents often helped (see family). Some people liked that the dermatology staff tried hard to fit around their schedules.
Deciding to try phototherapy

Everyone we spoke to who had tried phototherapy had been referred by their GP or dermatologist and their treatments took place at a hospital. Most had tried other psoriasis treatments before phototherapy, like steroids creams. An exception is Carys whose psoriasis was so extensive when she was diagnosed that her dermatologist said topical treatments wouldn’t work and she would need phototherapy. Even if the young person was already seeing a dermatologist, there could be a wait of a few weeks to months before their phototherapy treatment started.
Some people wanted to try phototherapy earlier. Zara’s mum had suggested phototherapy when she was younger but the doctors “always said there was something different to try” first. Steven was offered phototherapy by his dermatologist when he met the eligibility criteria based on severity/coverage. He thinks doctors also take into account the impacts on a person emotionally and socially (on hobbies, work life, relationships and friendships).
Side effects of phototherapy

A few people had side effects from phototherapy, such as burns. Gradually increasing the ‘doses’ (seconds) of UV helps limit the chances of this happening. Some people’s skins are more sensitive than others though. Carys had a ‘test’ patch done which went red. Louie sometimes felt sick after phototherapy which he thought was because he’s “fair skinned” and of “Irish descent”. Going out in the sun after phototherapy treatment increases the chances of sunburn. Megan’s mum called her school after each session to remind them that she should stay indoors.
The increased risk of skin cancer worried some people. Damini learnt about this in a letter from the hospital but her doctors reassured her that the number of UVB phototherapy sessions she was having wouldn’t be a big risk. Increased risks of skin cancer are particularly a concern with PUVA treatment, as the ultraviolet A light goes deeper into the skin.
A couple of people reported other side effects from UVB phototherapy. Zara stopped phototherapy when she developed a rash on her foot that wouldn’t heal. Hannah thinks her hyperpigmentation started whilst having phototherapy. Although no one talked about experiencing these, PUVA treatment can have other side effects and risks – like increased chances of developing cataracts (an eye condition which affects sight).

Outcomes of phototherapy

Nearly everyone we talked to who had phototherapy said it helped clear up their psoriasis, but the result often lasted only for a limited time. Lisa found her psoriasis came back as soon as she stopped phototherapy. An exception is Carys, who passed the “six months window” since finishing phototherapy without her psoriasis returning. 

Many said they thought their psoriasis returned slower and less severe after phototherapy. Although Zara had to stop phototherapy, she thinks the treatment helped slow the psoriasis. Steven regrets not moisturising more after finishing phototherapy as he thinks it might have helped. Abbie thinks stress triggered her psoriasis coming back on her scalp.
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Some people were pleased with the result from phototherapy, even though their psoriasis came back a few months later. Abbie liked seeing the progress during phototherapy and her boyfriend made encouraging comments. Lucy had three courses of phototherapy (including one of PUVA) and thinks the treatment is “fantastic and really works”. Adam’s phototherapy worked “really well” and felt like “normal skin again for the first time in my life”. 

Others found the emotional impact of the return of psoriasis outweighed the physical benefits from phototherapy. Hannah had two courses of phototherapy before trying systemic treatments. She says phototherapy worked well both times, but it was upsetting when her psoriasis came back after spending so much time going for treatment.


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