Phototherapy is primarily used to treat skin conditions like psoriasis and eczema. Over the course of many sessions, you’re exposed to safe, artificial UV light.

Phototherapy is a treatment that involves exposing the skin to ultraviolet (UV) light on a regular basis.

Also known as light therapy, it’s mostly used to treat inflammatory skin disorders, such as eczema and psoriasis. It may also be used to treat jaundice in newborn infants and some types of depression.

This article explores phototherapy treatment, safety, and efficacy.

Light therapy has been used for decades to treat a variety of skin conditions. It involves exposing your skin to UV light for a fixed amount of time several times per week, for several weeks.

There are several different types of UV light. Your dermatologist will tell you which types will work best for you.

Phototherapy typically involves some form of artificial light. Different types of lights are used to treat different conditions, this can include everything from fluorescent light bulbs to lasers.

Phototherapy can involve different wavelengths of UV light:

  • UVB: UVB light penetrates the top layer of skin. Broadband UVB light targets larger areas, while narrowband UVB light can be used for more targeted treatments.
  • UVA: UVA light has a longer wavelength that penetrates deeper layers of skin.
  • PUVA: UVA light is combined with a medication called psoralen. Psoralen makes the skin more sensitive to light to maximize the effects of exposure.

What is ultraviolet light?

Ultraviolet light is a type of energy that is measured using the electromagnetic spectrum. Other types of electromagnetic radiation include radio waves, microwaves, and X-rays, to name a few.

Sunlight is the best-known source of UV light. It consists of three types of UV rays: UVA, UVB, and UVC. The ozone layer actually absorbs all UVC rays, so most of the sunlight that you come into contact with on daily basis only consists of UVA and UVB rays.

Phototherapy is used to treat a variety of health conditions. This includes:

Depending on the severity of your condition, your doctor might suggest additional treatments prior to or alongside phototherapy.

Phototherapy is typically administered by a dermatologist in a doctor’s office or specialty clinic. Your experience will depend on what type of phototherapy your doctor prescribed, what condition you have, and where the problem areas are located.

Phototherapy is typically delivered using one of the following:

  • a whole-body chamber
  • a handheld wand
  • a smaller panel (for hands and feet)
  • a whole-body panel
  • a tabletop lamp
  • a specialized blue light blanket for newborns

Your initial dose and length of exposure are determined by your skin type. You can expect your doctor to gradually increase the dose as treatment progresses.

If you receive whole-body phototherapy, you’ll be required to wear UV-filtering goggles and cover your face and genitals. You may also be asked to avoid moisturizer, perfume, and cologne prior to your phototherapy session.

Phototherapy can sometimes be done at home. If you’re doing phototherapy at home, you’ll be instructed to spend a set amount of time exposing yourself to the artificial light from the phototherapy device.

If you use a handheld wand, you might be instructed to apply it only to affected areas, such as psoriasis plaques.

You can minimize the side effects of phototherapy by taking care of your skin after each session. This might include:

  • applying lotion twice daily
  • using a mild soap
  • taking short showers
  • avoiding hot water in the shower
  • only showering once per day

The effectiveness of phototherapy depends on the condition being treated. For skin conditions such as psoriasis and eczema, phototherapy is highly effective.

About 50% to 90% of people with psoriasis experience symptom relief or remission following light therapy.

However, the American Academy of Dermatology notes that phototherapy works best for people who are able to make it to their regular appointments. To see improvement, you may need to attend phototherapy sessions 2 to 5 days a week.

A 2021 review reported on several studies that showed UVB treatment led to a 60% reduction in eczema symptom severity in children. A smaller study in children with eczema found that after phototherapy, 76% experienced clear or almost-clear skin. About 53% still had clear skin at their 12-month follow-up.

Phototherapy is safe, though it can cause short-term side effects. Most are mild, and may include:

  • redness
  • dryness
  • tenderness
  • pain
  • tightness
  • itching
  • blistering

If you take medication alongside phototherapy, you might experience additional side effects. For example, PUVA treatment has been linked to nausea, feeling unwell, and fever.

In the long term, phototherapy can make your skin age faster, causing coarseness, wrinkling, or looseness.

According to a 2019 review, UVB phototherapy is not linked to an increased risk of skin cancer. PUVA treatment, however, has been linked to an increase in squamous cell carcinoma, particularly after many phototherapy sessions. As a result, it’s not prescribed as frequently.

Can I do phototherapy at home?

Some forms of phototherapy can be done at home. For example, if your light therapy prescription requires a handheld device, lightbox, or tabletop lamp, you can do it at home. For full-body phototherapy, you’ll have to visit a medical clinic.

How many phototherapy treatments will I need?

It depends on your condition. For example, if you have moderate or severe psoriasis, doctors recommend approximately 3 sessions per week for up to 12 weeks to see an improvement.

How does phototherapy work for jaundice?

Phototherapy helps to treat jaundice in newborns by aiding the body to break down a chemical called bilirubin. As bilirubin is broken down, it can be excreted in the urine and feces.

Can jaundice come back after phototherapy?

Newborn jaundice can return after phototherapy. If you return home from the hospital and find your baby is still showing signs of jaundice, you should contact a doctor right away. Your newborn may have to receive more phototherapy, and possibly other treatments.

Phototherapy is an effective treatment for a number of skin conditions. It involves exposing the skin to artificial light for a specified period of time several times per week. It works by delivering UV rays that help to minimize symptoms.

It carries a risk of mild side effects, such as redness and itchiness, but most types of phototherapy are not associated with an increased risk of skin cancer. To learn more, schedule an appointment with a dermatologist.