Phototherapy

What is phototherapy?

Phototherapy is a treatment for eczema that uses specific, safe wavelengths of ultraviolet (UV) light. Also known as light therapy, it can be used to treat many types of eczema in both adults and children. It helps ease eczema symptoms like itch and inflammation. Phototherapy must be prescribed by a doctor, typically a dermatologist.

Who is a good candidate for phototherapy?

Phototherapy can work for all types of eczema. However, it is typically prescribed to patients with moderate to severe eczema that hasn’t responded to topical treatments.

Phototherapy can be prescribed for eczema that is widespread, meaning all over the body, or for localized eczema, like on the hands and feet, that has not improved with topical medications.

What types of light are used in phototherapy for eczema?

The most common type of phototherapy for eczema uses narrowband ultraviolet B (NB-UVB) light. It earned its name for emitting a very narrow range of wavelengths of light within the UVB spectrum.

Phototherapy can also use ultraviolet A (UVA) light, which comes in a couple different forms. One form is called PUVA phototherapy, which is combined with an oral or topical medication that sensitizes the skin to the UVA light. This modality is now uncommonly used now due to increased risk of skin cancer development over long-term use.

A special machine is used to emit either UVB or UVA light for treatment in the dermatology clinic.

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How does phototherapy help eczema?

Phototherapy helps eczema by suppressing overactive immune cells in the skin, which is what triggers much of the inflammation linked to the disease. Phototherapy helps reduce redness, itch and can help improve eczema symptoms, especially when other treatments like topical medicines have not been successful.

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Who administers phototherapy treatment?

Your dermatologist prescribes phototherapy. However, not all dermatologists have phototherapy machines in their offices. If they do not have it in their medical office, they will refer you to another location that offers the treatment. Your dermatologist will set the treatment plan based on your unique needs, which is what the other office will follow.

Phototherapy sessions can be administered by a dermatologist. They can also be done by a nurse or medical assistant who is following the treatment plan set by the dermatologist.

Sometimes, you can even get a phototherapy machine in your home, but this depends on insurance approval.

What can you expect during a phototherapy treatment?

The phototherapy machine is typically a full-body booth. The procedure can vary slightly depending on the type of phototherapy machine.

For treatment, you’ll be asked to undress so the areas to be treated are exposed to receive direct light. The healthcare provider may ask you to keep sensitive areas covered like goggles to protect eyes or underwear to cover the genital area. You will step into the phototherapy booth and the door will be closed. The provider starts the machine and the machine’s lamps will emit light according to the dosage determined by your doctor. The light-emitting machine will be activated for a short time, usually a few minutes. When the lights turn off, the provider will open the door so you can leave the booth.

If you are undergoing PUVA phototherapy, you will be given an oral medication or apply a medicated cream to the skin before the phototherapy treatment.

Before each new treatment session, your provider will ask about your reaction and any side effects from the previous session.

How often do you have to go for phototherapy?

Eczema is unique in every person, so phototherapy is as well. The course of treatment is different for everyone, depending on the type of eczema and its severity. Treatments are individually prescribed according to the patient’s skin type, tendency to burn, current medications, amount of pigmentation in skin, the response of their eczema and whether they have had skin cancer in the past. Additionally, providers consider what medications you are taking to decide on treatment protocol. For example, certain antibiotics and hypertensive medications may cause a stronger response to phototherapy.

Generally, people start with a low dose treatment about three times per week. It may take one or two months of regular treatments before an improvement in symptoms is seen. Depending on results, that dose can be increased over time. If phototherapy is working well after a few months, your provider may reduce the number of sessions per week.

A trial period for phototherapy is usually three to six months. If you hit six months and aren’t seeing any results, your doctor will typically want to move on to a different treatment option.

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What are the side effects of phototherapy for eczema patients?

Phototherapy is generally considered safe for eczema patients. Phototherapy targets only the skin. However, like all treatments, there are possible side effects to consider with phototherapy.

The potential side effects of phototherapy include:

• Sunburn and skin tenderness
• Premature skin aging
• Photosensitive skin eruptions
• Nonmelanoma skin cancer (from UVA treatment)
• Cataracts (from UVA treatment)

According to research, the increased risk of skin cancer is quite low with targeted phototherapy. For those undergoing PUVA phototherapy treatment, the accompanying oral medication may have side effects like nausea or vomiting, headaches, increased sun sensitivity and cataracts. Wearing sunscreen daily and reapplying as needed is even more crucial when undergoing phototherapy.

Medically reviewed on May 5, 2025.