Table of ContentsView AllTable of ContentsWhat Is Light Therapy?Types of Light TherapyRisks and ContraindicationsTreatment
Table of ContentsView All
View All
Table of Contents
What Is Light Therapy?
Types of Light Therapy
Risks and Contraindications
Treatment
Light therapy for psoriasis is an effective treatment. Ultraviolet (UV) light therapy (phototherapy) involves exposing the skin to controlled amounts of UV radiation similar to that from the sun.
Science Photo Library / Getty Images
It has been known for centuries that sunlight can improve many inflammatory skin conditions, including psoriasis andatopic dermatitis(eczema).
Phototherapy, or light therapy, is a type of treatment that uses certain types of ultraviolet (UV) light to improve a health condition. UV radiation has immunosuppressive and anti-inflammatory effects that can help temper theinflammationthat drives many of these diseases.
The sun gives off electromagnetic energy in various forms. Of these, UV radiation is the type that has a shorter wavelength and more energy than visible light. There are two types used in phototherapy:
Types of Light Therapy for Psoriasis
Beginning in the early 20thcentury, clinicians began to develop different types of phototherapy to help people with psoriasis.
Today there are several forms used to treat the disease, including:
Although limited exposure to the sun can be beneficial to the skin, phototherapy is preferred for moderate to severe psoriasis because the UV radiation can be dosed and controlled.
BB-UVB and NB-UVB
Broadband ultraviolet B (BB-UVB) was the first type of phototherapy developed. It involves exposing the skin to wavelengths of light between 290 and 313 nanometers (nm).
Years later, researchers developed a UVB therapy that uses smaller wavelengths (between 308 and 313 nm). That is why it is called “narrow band.”
Narrowband ultraviolet B (NB-UVB) is the most common type of phototherapy used today, for several reasons:
Both BB-UVB and NB-UVB therapy can benefit from the application ofcoal tarto the skin. The procedure, referred to as Goeckerman therapy, appears to enhance the effects of phototherapy.
PUVA
Psoralen plus ultraviolet A (PUVA), the second-most common form of phototherapy, is performed in two parts.
Because UVA radiation is not as strong as UVB, you need this extra boost to make the therapy effective.
Laser Excimer Therapy
A newer and less commonly used form of phototherapy is called laser excimer therapy. It is a form of UVB-NB therapy in which the beam of light is narrowed to target smaller areas of skin. The lasers deliver higher doses of radiation, which can help treat the skin more quickly.
Side effects are typically mild, but it might hurt a bit for some people. Treated areas may have bruising, sunburns, and possibly scarring.
What Is LED Light Therapy?LED (light-emitting diode) therapyuses lights of different wavelengths to treat a variety of skin conditions, including acne, eczema, and psoriasis. LED light therapy devices are available without a prescription and, unlike other types of phototherapy, don’t use UV radiation.Research shows that certain wavelengths of visible light can work against plaque psoriasis. The Food and Drug Administration has approved a wearable, blue-light device for treatingmild psoriasisat home.
What Is LED Light Therapy?
LED (light-emitting diode) therapyuses lights of different wavelengths to treat a variety of skin conditions, including acne, eczema, and psoriasis. LED light therapy devices are available without a prescription and, unlike other types of phototherapy, don’t use UV radiation.Research shows that certain wavelengths of visible light can work against plaque psoriasis. The Food and Drug Administration has approved a wearable, blue-light device for treatingmild psoriasisat home.
LED (light-emitting diode) therapyuses lights of different wavelengths to treat a variety of skin conditions, including acne, eczema, and psoriasis. LED light therapy devices are available without a prescription and, unlike other types of phototherapy, don’t use UV radiation.
Research shows that certain wavelengths of visible light can work against plaque psoriasis. The Food and Drug Administration has approved a wearable, blue-light device for treatingmild psoriasisat home.
Pulsed Dye Laser (PDL)
Pulsed dye laser therapy was first used to treat psoriasis in 1992.
PDL is a safe and effective treatment for topical plaque psoriasis over small areas. Additionally, PDL provides optimal outcomes as a nail psoriasis treatment, compared with other lasers.
PDL may be preferred because UVA and UVB penetration is poor in fingernails, and nail plates (the visible part of the nail that sits on the nail bed) completely block UVB.
Grenz Rays
Grenz rays are a less commonly used treatment option for psoriasis—rarely used today.
Treatment with Grenz rays involves exposure to low-energy (ultrasoft) X-rays. Grenz rays are a form of black light with a very low penetration power.
Grenz is occasionally utilized to treat skin conditions that don’t fully resolve with other treatments. Grenz treatments are not a replacement for other therapies but rather an add-on that may help deliver better results.
Indications
Studies show that phototherapy can effectively treat:
However, phototherapy is rarely used on its own. It is generally recommended when topical therapies, such ascorticosteroids, are unable to provide relief.
Phototherapy can be used to enhance the effects of topical therapies. For moderate to severe psoriasis, phototherapy is often used with oral or injectable drugs that temper inflammation from within. These include:
Phototherapy is often an attractive option since it is cost-effective, has few side effects, and can be used during pregnancy, unlike some otherpsoriasis treatments.
Most people do relatively well with phototherapy. However, it may cause side effects in some, including:
Long-term side effects include:
Less commonly, psoralen used in PUVA phototherapy may cause nausea. Since PUVA is performed in a standing lightbox, protective eye goggles are needed to preventcataractsthat may develop as a result of the increased light sensitivity.
Skin Cancer Risk
Some older studies suggested that phototherapy may increase the risk of skin cancer, particularly a type known assquamous cell cancer.
The risk may be highest in people who get PUVA therapy over an extended period, although UVB therapy may also increase the risk. The current evidence, however, suggests the risk is extremely low.
According to a 2015 review of studies, there is no clear evidence of an increased skin cancer risk associated with UVB phototherapy among all skin types.
To be on the safe side, healthcare providers recommend having regularskin screeningsto check for any pre-cancerous lesions. If you have concerns about cancer, don’t hesitate to discuss them with your dermatologist before treatment.
UV radiation used for phototherapy should not be confused with the ionizing radiation used forX-rays. UV radiation mimics sunlight, while high-energy ionizing radiation can damage the DNA in cells, potentially causing cancer.
Contraindications
Despite the benefits of phototherapy, it may not be a good option if someone:
People with fair skin may also need to be cautious, as they are more likely to experience irritation.
Before Phototherapy
Before a light therapy session is even scheduled, a dermatologist will perform a head-to-toe examination of your skin and ask about a family history of skin cancer orphotosensitizing disorders.
At this time, advise your healthcare provider about any and all drugs and supplements you are taking. This includes patches, creams, and over-the-counter remedies. Some medications, such asretinoids, certain antibiotics, and chemotherapy drugs, can make your skin more sensitive to UV light.
If you are having PUVA therapy, you may be asked to see an ophthalmologist to have an eye exam before you begin.
Timing
Your first light therapy treatment may last only a few seconds. Over time, the sessions will increase based on your skin type, tolerance to treatment, and the strength of the light used. Treatments rarely last longer than a few minutes.
Several treatments are usually required each week:
Treatments generally continue until your skin is clear. Maintenance treatments are sometimes needed to prevent acute flares.
Location
Phototherapy is typically done in a dermatologist’s office in a 5- x 7-foot lightbox. Newer handheld devices are also available for spot treatments, while full-body lamps and lightboxes can treat the hands and feet.
Home phototherapy units are also available and are typically used for maintenance.
What to Wear
No special clothing is needed for your appointment, but you may want to bring older clothes if your healthcare provider plans to use coal tar. Coal tar not only smells but can stain your clothes if you happen to get some on your hands.
If your arms are being treated, a lightweight, long-sleeved shirt may help prevent sun exposure on the way home. Soft socks and a pair of open-toe sandals can do the same if your feet are sore or sunburned after treatment.
Cost and Health Insurance
Check with your insurance company to find out if phototherapy is covered in your schedule of benefits and what yourcopay or coinsurancecosts will be.
What to Bring
If coal tar is being used, you may want to bring a nailbrush and some deodorant to help minimize the smell. A moisturizing cream can also help.
You should also bring sunscreen, sunglasses, and a hat to reduce sun exposure when outdoors, especially if psoralen is used.
During Phototherapy
When you arrive, you will be escorted to a changing room and asked to remove any clothes that cover the skin being treated. Areas that do not need treatment should be covered and protected as much as possible.
If needed, the following protective tools may be provided:
Coal tar or topical psoralen will be applied to the affected skin if needed. If oral psoralen is used, you will be asked to take it one to two hours before the procedure.
If undergoing PUVA therapy to treat a large area of skin, you may be asked to soak in a bath of psoralen solution for several minutes.
UVB treatment could involve soaking in an indoor salt bath while undergoing light exposure (calledbalneophototherapy).
Once prepared, you will either receive treatment in a lightbox or with a handheld device while standing or sitting. The actual procedure may induce a warm sensation, similar to that of a mild sunburn.
Once the session is completed, you can shower or wash and change back into your clothes. The condition of your skin will be checked and medication recommended if you have any discomfort.
After Phototherapy
It is important to avoid natural sunlight after receiving phototherapy. This is especially true for the first 24 hours when skin will be most inflamed. Some precautions to take include:
While skin redness and irritation are common after phototherapy, contact your healthcare provider if you experience blisters, rash, burns, ulcers, drainage, or a fever of 100.4 degrees F or more.
Upon the completion of therapy, you’ll typically schedule a follow-up to evaluate your response and the need for maintenance therapy. You may also be asked to see your ophthalmologist for a follow-up examination of your eyes.
Summary
Phototherapy, or light therapy, is atype of treatmentthat uses UV light to improve certain conditions, including psoriasis. When moderate to severe psoriasis is not controlled with topical medications, light therapy may be an appropriate option.
Several forms of UV light are used to treat psoriasis including, BB-UVB, NB-UVB, PUVA, and laser excimer therapy. Each has a unique treatment schedule and maintenance follow-up. All increase the risk of sun damage immediately after treatment. Precautionary aftercare includes avoiding sun exposure, using an oral antihistamine or steroid cream, and moisturizing frequently.
If you notice any blisters, rash, burns, ulcers, drainage, or fever consult your healthcare provider.
13 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American Academy of Dermatology Association.Psoriasis treatment: Phototherapy.InformedHealth.org [Internet].Psoriasis: Learn More – Does light therapy (phototherapy) help reduce psoriasis symptoms?Nakamura M, Farahnik B, Bhutani T.Recent advances in phototherapy for psoriasis.F1000Research. 2016;5:F1000 Faculty Rev-1684. doi:10.12688/f1000research.8846.1Elmets CA, Lim HW, Stoff B, et al.Joint American Academy of Dermatology-National Psoriasis Foundation guidelines of care for the management and treatment of psoriasis with phototherapy [published correction appears in J Am Acad Dermatol. 2020 Mar;82(3):780. doi: 10.1016/j.jaad.2019.11.024].J Am Acad Dermatol. 2019;81(3):775-804. doi:10.1016/j.jaad.2019.04.042American Academy of Dermatology Association.Can a wearable blue-light device clear psoriasis?Zhang P, Wu MX.A clinical review of phototherapy for psoriasis.Lasers Med Sci. 2018;33(1):173-180. doi:10.1007/s10103-017-2360-1Tawfik AA.Novel treatment of nail psoriasis using the intense pulsed light: a one-year follow-up study.Dermatol Surg. 2014;40(7):763-768. doi:10.1111/dsu.0000000000000048American Osteopathic College of Dermatology.Grenz Rays.Valejo Coelho MM, Apetato M.The dark side of the light: Phototherapy adverse effects.Clinics in Dermatology. 2016;34(5):556-562. doi:10.1016/j.clindermatol.2016.05.005Geller S, Xu H, Lebwohl M, Nardone B, Lacouture ME, Kheterpal M.Malignancy Risk and Recurrence with Psoriasis and its Treatments: A Concise Update.Am J Clin Dermatol. 2018;19(3):363-375. doi:10.1007/s40257-017-0337-2Wang, E.; Sasaki, J.; Nakamura, M. et al.Cutaneous carcinogenic risk of phototherapy: an updated comprehensive review.J Psoriasis Psoriatic Dis.2015;1(1). doi:10.1177/247553031500100107National Psoriasis Foundation.Phototherapy.Peinemann F, Harari M, Peternel S, et al.Indoor balneophototherapy for chronic plaque psoriasis: Abridged Cochrane Review.Dermatol Ther. 2021;34(1):e14588. doi:10.1111/dth.14588Additional ReadingMenter A, Korman N, Elmets C, et al.Guidelines of care for the management of psoriasis and psoriatic arthritis: Section 5. Guidelines of care for the treatment of psoriasis with phototherapy and photochemotherapy.J Am Acad Dermatol. 2010;62(1):114-35. doi:10.1016/j.jaad.2009.08.026
13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American Academy of Dermatology Association.Psoriasis treatment: Phototherapy.InformedHealth.org [Internet].Psoriasis: Learn More – Does light therapy (phototherapy) help reduce psoriasis symptoms?Nakamura M, Farahnik B, Bhutani T.Recent advances in phototherapy for psoriasis.F1000Research. 2016;5:F1000 Faculty Rev-1684. doi:10.12688/f1000research.8846.1Elmets CA, Lim HW, Stoff B, et al.Joint American Academy of Dermatology-National Psoriasis Foundation guidelines of care for the management and treatment of psoriasis with phototherapy [published correction appears in J Am Acad Dermatol. 2020 Mar;82(3):780. doi: 10.1016/j.jaad.2019.11.024].J Am Acad Dermatol. 2019;81(3):775-804. doi:10.1016/j.jaad.2019.04.042American Academy of Dermatology Association.Can a wearable blue-light device clear psoriasis?Zhang P, Wu MX.A clinical review of phototherapy for psoriasis.Lasers Med Sci. 2018;33(1):173-180. doi:10.1007/s10103-017-2360-1Tawfik AA.Novel treatment of nail psoriasis using the intense pulsed light: a one-year follow-up study.Dermatol Surg. 2014;40(7):763-768. doi:10.1111/dsu.0000000000000048American Osteopathic College of Dermatology.Grenz Rays.Valejo Coelho MM, Apetato M.The dark side of the light: Phototherapy adverse effects.Clinics in Dermatology. 2016;34(5):556-562. doi:10.1016/j.clindermatol.2016.05.005Geller S, Xu H, Lebwohl M, Nardone B, Lacouture ME, Kheterpal M.Malignancy Risk and Recurrence with Psoriasis and its Treatments: A Concise Update.Am J Clin Dermatol. 2018;19(3):363-375. doi:10.1007/s40257-017-0337-2Wang, E.; Sasaki, J.; Nakamura, M. et al.Cutaneous carcinogenic risk of phototherapy: an updated comprehensive review.J Psoriasis Psoriatic Dis.2015;1(1). doi:10.1177/247553031500100107National Psoriasis Foundation.Phototherapy.Peinemann F, Harari M, Peternel S, et al.Indoor balneophototherapy for chronic plaque psoriasis: Abridged Cochrane Review.Dermatol Ther. 2021;34(1):e14588. doi:10.1111/dth.14588Additional ReadingMenter A, Korman N, Elmets C, et al.Guidelines of care for the management of psoriasis and psoriatic arthritis: Section 5. Guidelines of care for the treatment of psoriasis with phototherapy and photochemotherapy.J Am Acad Dermatol. 2010;62(1):114-35. doi:10.1016/j.jaad.2009.08.026
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
American Academy of Dermatology Association.Psoriasis treatment: Phototherapy.InformedHealth.org [Internet].Psoriasis: Learn More – Does light therapy (phototherapy) help reduce psoriasis symptoms?Nakamura M, Farahnik B, Bhutani T.Recent advances in phototherapy for psoriasis.F1000Research. 2016;5:F1000 Faculty Rev-1684. doi:10.12688/f1000research.8846.1Elmets CA, Lim HW, Stoff B, et al.Joint American Academy of Dermatology-National Psoriasis Foundation guidelines of care for the management and treatment of psoriasis with phototherapy [published correction appears in J Am Acad Dermatol. 2020 Mar;82(3):780. doi: 10.1016/j.jaad.2019.11.024].J Am Acad Dermatol. 2019;81(3):775-804. doi:10.1016/j.jaad.2019.04.042American Academy of Dermatology Association.Can a wearable blue-light device clear psoriasis?Zhang P, Wu MX.A clinical review of phototherapy for psoriasis.Lasers Med Sci. 2018;33(1):173-180. doi:10.1007/s10103-017-2360-1Tawfik AA.Novel treatment of nail psoriasis using the intense pulsed light: a one-year follow-up study.Dermatol Surg. 2014;40(7):763-768. doi:10.1111/dsu.0000000000000048American Osteopathic College of Dermatology.Grenz Rays.Valejo Coelho MM, Apetato M.The dark side of the light: Phototherapy adverse effects.Clinics in Dermatology. 2016;34(5):556-562. doi:10.1016/j.clindermatol.2016.05.005Geller S, Xu H, Lebwohl M, Nardone B, Lacouture ME, Kheterpal M.Malignancy Risk and Recurrence with Psoriasis and its Treatments: A Concise Update.Am J Clin Dermatol. 2018;19(3):363-375. doi:10.1007/s40257-017-0337-2Wang, E.; Sasaki, J.; Nakamura, M. et al.Cutaneous carcinogenic risk of phototherapy: an updated comprehensive review.J Psoriasis Psoriatic Dis.2015;1(1). doi:10.1177/247553031500100107National Psoriasis Foundation.Phototherapy.Peinemann F, Harari M, Peternel S, et al.Indoor balneophototherapy for chronic plaque psoriasis: Abridged Cochrane Review.Dermatol Ther. 2021;34(1):e14588. doi:10.1111/dth.14588
American Academy of Dermatology Association.Psoriasis treatment: Phototherapy.
InformedHealth.org [Internet].Psoriasis: Learn More – Does light therapy (phototherapy) help reduce psoriasis symptoms?
Nakamura M, Farahnik B, Bhutani T.Recent advances in phototherapy for psoriasis.F1000Research. 2016;5:F1000 Faculty Rev-1684. doi:10.12688/f1000research.8846.1
Elmets CA, Lim HW, Stoff B, et al.Joint American Academy of Dermatology-National Psoriasis Foundation guidelines of care for the management and treatment of psoriasis with phototherapy [published correction appears in J Am Acad Dermatol. 2020 Mar;82(3):780. doi: 10.1016/j.jaad.2019.11.024].J Am Acad Dermatol. 2019;81(3):775-804. doi:10.1016/j.jaad.2019.04.042
American Academy of Dermatology Association.Can a wearable blue-light device clear psoriasis?
Zhang P, Wu MX.A clinical review of phototherapy for psoriasis.Lasers Med Sci. 2018;33(1):173-180. doi:10.1007/s10103-017-2360-1
Tawfik AA.Novel treatment of nail psoriasis using the intense pulsed light: a one-year follow-up study.Dermatol Surg. 2014;40(7):763-768. doi:10.1111/dsu.0000000000000048
American Osteopathic College of Dermatology.Grenz Rays.
Valejo Coelho MM, Apetato M.The dark side of the light: Phototherapy adverse effects.Clinics in Dermatology. 2016;34(5):556-562. doi:10.1016/j.clindermatol.2016.05.005
Geller S, Xu H, Lebwohl M, Nardone B, Lacouture ME, Kheterpal M.Malignancy Risk and Recurrence with Psoriasis and its Treatments: A Concise Update.Am J Clin Dermatol. 2018;19(3):363-375. doi:10.1007/s40257-017-0337-2
Wang, E.; Sasaki, J.; Nakamura, M. et al.Cutaneous carcinogenic risk of phototherapy: an updated comprehensive review.J Psoriasis Psoriatic Dis.2015;1(1). doi:10.1177/247553031500100107
National Psoriasis Foundation.Phototherapy.
Peinemann F, Harari M, Peternel S, et al.Indoor balneophototherapy for chronic plaque psoriasis: Abridged Cochrane Review.Dermatol Ther. 2021;34(1):e14588. doi:10.1111/dth.14588
Menter A, Korman N, Elmets C, et al.Guidelines of care for the management of psoriasis and psoriatic arthritis: Section 5. Guidelines of care for the treatment of psoriasis with phototherapy and photochemotherapy.J Am Acad Dermatol. 2010;62(1):114-35. doi:10.1016/j.jaad.2009.08.026
Meet Our Medical Expert Board
Share Feedback
Was this page helpful?Thanks for your feedback!What is your feedback?OtherHelpfulReport an ErrorSubmit
Was this page helpful?
Thanks for your feedback!
What is your feedback?OtherHelpfulReport an ErrorSubmit
What is your feedback?
