Phototherapy is a highly effective and widely used clinical treatment for psoriasis within the United Kingdom. It is typically considered a second-line therapy, meaning it is offered to patients when topical creams and ointments have failed to provide adequate control or when the psoriasis is too widespread to treat with creams alone. Administered under strict medical supervision in hospital-based dermatology departments or specialist clinics, phototherapy uses specific wavelengths of ultraviolet (UV) light to slow down the rapid production of skin cells and reduce inflammation. In the UK, this treatment is governed by NICE guidelines to ensure its safety and effectiveness.
What We’ll Discuss in This Article
- The role of phototherapy in the UK psoriasis care pathway.
- Differences between Narrowband UVB and PUVA therapy.
- The typical frequency and duration of a treatment course.
- The availability of home-based phototherapy on the NHS.
- Safety protocols and long-term risks of UV exposure.
- How to access light therapy through a dermatologist referral.
Types of phototherapy in the UK
There are two primary forms of light therapy used for psoriasis in the UK. Your dermatologist will decide which is most appropriate based on your skin type and the severity of your condition.
Narrowband UVB (NB-UVB)
This is the most common form of phototherapy used today. It uses a very specific wavelength of ultraviolet B light (approximately 311nm to 313nm). Unlike natural sunlight or broad-band UV, this narrow spectrum is highly effective at treating psoriasis while minimising the risk of burning. Most patients stand in a walk-in cabinet lined with fluorescent tubes for a few seconds to several minutes per session.
PUVA (Psoralen + UVA)
PUVA stands for psoralen plus ultraviolet A. Psoralen is a medication (taken as a tablet, a bath soak, or a cream) that makes the skin extra sensitive to UVA light. Because UVA penetrates deeper into the skin than UVB, PUVA is often reserved for severe cases or for thick plaques on the palms and soles of the feet. When taking the tablet form, patients must wear UV-protective glasses for 24 hours after treatment to protect their eyes from cataracts.
The treatment process and frequency
In the UK, a course of phototherapy is an intensive commitment. It is not a one-off treatment but a cumulative process that builds up the skin’s tolerance and suppresses the immune response over several weeks.
- Frequency: Most patients attend sessions two or three times a week.
- Duration: A typical course lasts between 6 and 12 weeks, usually involving a total of 15 to 30 sessions.
- Dosing: The first session is often less than a minute. The duration is gradually increased at each visit based on how your skin responded to the previous dose.
- Remission: Many patients find their skin clears entirely by the end of the course, with results lasting for several months or even years.
Home-based phototherapy options
While the majority of phototherapy in the UK is conducted in hospitals, some NHS trusts now offer home-based phototherapy for suitable patients. This involves a specialist team delivering a medical-grade UV unit to the patient’s home and providing intensive training on its use.
Home therapy is highly convenient for those who work or have childcare commitments, but it is not available in every region. Patients must still be under the regular supervision of a dermatologist and are required to keep strict logs of their treatment times. It is important to note that medical home units are far more advanced and safer than commercial sunbeds, which the NHS strongly advises against using.
Safety and long-term risks
Because phototherapy involves exposure to concentrated UV radiation, it is managed with high safety standards.
- Short-term risks: These include a mild “sunburn” reaction, dry skin, and occasionally an itchy rash.
- Long-term risks: Repeated courses of UV light can lead to premature skin ageing and an increased risk of non-melanoma skin cancer.
- Monitoring: The NHS keeps a lifetime record of the total number of phototherapy sessions a patient has received. Once a certain threshold is reached (often around 150 to 200 sessions for UVB), your dermatologist may recommend moving to systemic or biological treatments to avoid further UV exposure.
Conclusion
Phototherapy remains a cornerstone of psoriasis management in the UK, offering a powerful alternative for those who find topical treatments insufficient. Whether using Narrowband UVB or PUVA, the treatment provides a controlled, evidence-based way to achieve clear skin. While the time commitment can be significant, the high success rate and the potential for long-term remission make it a preferred choice for many. If you feel your psoriasis is no longer responding to creams, discuss a referral to a dermatology phototherapy unit with your GP.
Is phototherapy the same as using a sunbed?
No; sunbeds use a broad spectrum of UV light that is less effective for psoriasis and carries a much higher risk of skin damage. Hospital units use specific, filtered wavelengths.
Can I have phototherapy while pregnant?
Narrowband UVB is generally considered safe during pregnancy, although PUVA is usually avoided due to the psoralen medication.
Will my skin look worse before it gets better?
In the first week or two, your skin may look slightly pinker or feel drier, but the scaling and thickness of the plaques should begin to reduce shortly after.
Does phototherapy work for scalp psoriasis?
It can be difficult for light to reach the scalp through the hair. Special UV combs or targeted lasers are sometimes used for this specific area.
What should I wear during the session?
You will typically be asked to undress to your underwear so that all affected areas are exposed. Goggles must be worn to protect the eyes.
Can I use my usual creams during light therapy?
Some creams, such as coal tar or certain steroids, can make the skin more sensitive to light. You must tell the phototherapy nurse exactly what you are using.
How do I get referred for phototherapy?
You must be referred by a consultant dermatologist. If your GP thinks you are a candidate, they will first refer you to a dermatology clinic for an assessment.
Authority Snapshot (E-E-A-T Block)
This article examines the clinical application and safety of phototherapy for psoriasis within the UK healthcare system. It is written by the MyPatientAdvice Medical Writing/Research Team and reviewed by Dr. Rebecca Fernandez, a UK-trained physician with experience in dermatology and primary care. All guidance is strictly aligned with the clinical standards provided by the NHS and NICE for 2026.
