Light Therapy for Psoriasis: Does It Work?

Psoriasis is an autoimmune disorder that causes skin cells to grow too rapidly—resulting in red, itchy lesions on the surface of the skin. Phototherapy, or light therapy, is a treatment that continues to be one of the most effective treatment options for psoriasis.

With light therapy, ultraviolet (UV) light slows skin cell growth that contributes to psoriasis. Different types are available, from ultraviolet B (UVB) light therapy to laser treatment, for administration at home or in a dermatologist's office. Here's what else you need to know.

Types of Light Therapy

Phototherapy is usually administered on an outpatient basis in a dermatologist's office using a walk-in light booth that looks like a tanning bed standing on end. There are also light therapy options for home use. Overall, treatment can last as little as four weeks or as long as three months.

UVB Light Therapy

Ultraviolet B light (UVB), one of the components of sunlight, is especially effective for treating psoriasis. UVB light therapy comes in two forms for treating generalized plaque psoriasis:

• Narrow-band UVB (NB-UVB): Uses a small range of wavelengths. The usual treatment course is two to three times per week, with maintenance treatment weekly with symptom improvement.
• Broad-band UVB (BB-UVB): Uses a broad UV wavelength spectrum. The typical treatment plan may range from three to five treatment sessions weekly. Also, BB-UVB is less effective than NB-UVB.

UVA Light Therapy

Although not as potent as UVB, ultraviolet A light (UVA) is also used to treat psoriasis and effectively clears lesions. UVA light is often combined with an oral medication, psoralen. Together, they are a treatment called PUVA. PUVA may be completed in two different ways:

• PUVA bath: Involves soaking in water with psoralen, waiting for a specific amount of time, and receiving UVA light therapy afterward
• PUVA with pills: Involves taking psoralen pills, waiting for 45 to 60 minutes, and receiving UVA light therapy afterward

Targeted UVB Therapy

For cases where areas of psoriasis are smaller, a dermatologist may recommend targeted UVB therapy to treat the affected areas only. For example, excimer laser therapy is FDA-approved for plaque psoriasis treatment. You may receive targeted therapy two to three times per week.

At-Home Light Therapy

Light boxes for home use are also available. Home NB-UVB may be an option for people who may not be able to receive phototherapy sessions in a dermatologist's office on a long-term basis. The initial treatment will start at the office, but the person can continue a provider-guided treatment schedule at home.

How Effective Is Light Therapy?

Light therapy is highly effective in general. At least half but up to 90% of individuals see a reduction or improvement in symptoms.

Mild psoriasis cases can benefit from targeted light therapy, along with using other treatment options. Also, light therapy best helps people with moderate-to-severed psoriasis when used as part of combination therapy. For example, a person may have a treatment plan that uses light therapy with medications like biologics—medicines made from natural sources.

Which Light Therapy Is Best for Psoriasis?

Overall, NB-UVB is the most effective and safest option for light therapy. As a result, it's used more often compared to other options.

PUVA can be effective. Specifically, PUVA bath therapy has been shown to be more helpful for psoriasis symptom relief than UVB light therapy on its own. Still, PUVA therapy commonly causes side effects and has an increased risk for skin cancer.

Risks of Light Therapy

There are some risks of using light therapy as a psoriasis treatment, which include side effects and skin cancer risks. Also, some individuals cannot use the treatment.

Contraindications

Everyone with psoriasis will not be able to use light therapy. It's not a recommended treatment for people with:

• A history of melanoma or other types of skin cancer
• Medical conditions that make them likely to develop skin cancer or sensitive to UV light
• A treatment plan that includes medications that make them sensitive to UV light, such as diuretics or antibiotics

Side Effects

Phototherapy can result in side effects, such as:

• Blisters and burning, which are both rare
• Dark spots on the skin, which more often occur in individuals with darker skin tones
• Itching
• Mild stinging or burning
• Sunburn-like reactions

There are also potential long-term side effects, including freckles, skin aging, and increased skin cancer risk. However, a dermatologist can assist in managing these effects.

Skin Cancer

PUVA carries a long-term risk of skin cancer, especially in patients with fair skin. The psoralen molecule used in PUVA is considered the source of the increased risk. Psoralen enters the body's cells and changes their DNA when activated by UV light. This process kills off immune cells close to the skin and helps control psoriasis, but it also leads to damage that could cause skin cancer later.

Because of the risk of skin cancer, PUVA is typically reserved for the most severe and stubborn psoriasis cases. UVB light is known to cause skin cancer as well, but studies have not shown any increased risk of skin cancer among psoriasis patients who have undergone UVB phototherapy.

Other Risk Considerations

Natural sunlight may be helpful for psoriasis, but talk with a healthcare provider before using sunlight as a treatment. Too much sun exposure can lead to sunburns, which can worsen psoriasis. A provider can guide you about sunlight exposure safety if they recommend natural sunlight as a treatment.

Commercial tanning beds are not recommended for treating psoriasis. Using a tanning bed for psoriasis can worsen psoriasis by causing skin damage. There's also the potential for tanning bed use to increase the risk of skin cancer.

Living With and Managing Psoriasis

There is no cure for psoriasis; it's a skin condition that can last your entire life. There may be times when psoriasis goes away but later comes back. Engaging in proper treatment can help you manage the condition and reduce the risk of developing other health conditions like diabetes and heart disease.

A Quick Review

Light therapy is a common, effective treatment for small areas of psoriasis or psoriasis that covers much of the body. It's available in different types administered at a healthcare facility or home. Though this psoriasis treatment can be beneficial, it does come with side effects, and certain individuals may not be able to use light therapy. Talk with a healthcare provider or dermatologist to determine if light therapy is an appropriate treatment option for you.