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Photothérapie UVB et psoriasis.

UVB Phototherapy for Alleviating Psoriasis

On the scalp, in the palm of the hands, on skin folds... psoriasis can manifest on various parts of the body. The level of pain or itching varies from person to person. To alleviate these dry and irritating patches, phototherapy may be prescribed. This treatment uses ultraviolet rays to control the disease and limit its effects. This article provides an overview of this technique.

Published February 19, 2024, by Manon, Scientific Editor — 3 min read

What is targeted UVB phototherapy?

Phototherapy, also known as light therapy, is a method of treating psoriasis by projecting ultraviolet rays onto the affected area. The goal is to replicate the beneficial effects of the sun on psoriasis. Many types of phototherapy have been developed and used for the treatment of psoriasis over the past few decades.

We notably find broadband ultraviolet B phototherapy or BB-UVB (290-320 nm), which was quickly replaced bynarrowband ultraviolet B phototherapy or NB-UVB (311 nm), deemed more effective. Finally, theexcimer laser at 308 nm was then invented in 1997 as a monochromatic UVB source.

NB-UVB and excimer laser are currently the first-line treatments used for treating stable plaque psoriasis. These techniques are also often recommended in the treatment of scalp psoriasis, as well as psoriasis on the palms of the hands and soles of the feet.

When to follow a UVB phototherapy?

For some individuals, the application of an over-the-counter cream or a prescribed cream is sufficient to soothe discomfort and slow the development of plaques. However, this is not the case for everyone. Therefore, if itching and scaling persist after your initial treatment, you may proceed to phototherapy, of course, based on the medical advice of your dermatologist.

UVB therapy is typically intended for lesions covering at least 10% of the body surface area. In certain specific cases, such as palmoplantar psoriasis which covers much less body surface area, it can also be treated with UV light. This type of treatment should be carried out under the supervision of a doctor. Even though the principle seems similar, phototherapy is different from tanning sessions carried out in salons. Due to its possible side effects (skin aging, cancer, or eye damage), medical supervision is mandatory.

How does UVB phototherapy proceed?

UVB phototherapy can be performed 2 to 3 times per week, with each session lasting a few minutes. It takes place in a dermatology office. Regardless of whether the individual responds to the treatment or not, the sessions cannot be extended or multiplied. Therefore, UVB phototherapy for controlling psoriasis is solely intended for adults due to the potential for adverse effects. To prevent UV overexposure, it is recommended to protect the skin between each session. To do this, opt for covering clothing, wear sunglasses, and use a sunscreen during your sun exposures.


ZANOLLI M. Phototherapy arsenal in the treatment of psoriasis. Dermatologic Clinics (2004).

ZHANG P. & al. A clinical review of phototherapy for psoriasis. Lasers in Medical Science (2018).


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