Tell us about your symptoms and treatment experience. Take our survey here.

Phototherapy to Treat Eczema

Reviewed by: HU Medical Review Board | Last reviewed: October 2023 | Last updated: October 2023

Phototherapy uses certain wavelengths of light to treat atopic dermatitis (also known as eczema). It is sometimes called light therapy. Phototherapy may be used if your eczema affects large parts of your body. It also may be used if you have smaller lesions that do not respond to topical treatments.1

Before choosing phototherapy, your doctor may want to try to manage your eczema with a home skin-care routine and topical treatments. Or your doctor may prescribe phototherapy while you are still using other therapies.1-3

Phototherapy is usually given in a healthcare office. Home-based units are available, but they are expensive and thus used less often.3

How does phototherapy work?

Some wavelengths of ultraviolet (UV) light affect the immune system. Exposing the skin to these wavelengths for a short time can reduce inflammation and itchiness caused by eczema.4

Most people get phototherapy at a doctor’s office, where a machine sends UV light to affected parts of the skin. The machine will emit this therapeutic light for only a few seconds to a few minutes.1

You may need to step inside a light-emitting machine while wearing limited clothing. You will need to wear goggles to protect your eyes. Your affected skin must remain exposed to the light.1

Your doctor may increase the amount of light each time as you receive more therapy sessions. If you are using topical treatments, you may find that you need less of them as your phototherapy progresses. As your skin improves, you may need fewer light therapy sessions.1,2


Phototherapy comes in many different forms, including:1,2,5,6

  • Sunlight
  • Narrowband ultraviolet B (NB-UVB) light
  • Broadband UVB light
  • Ultraviolet A (UVA) light
  • UVA and UVB lights combined
  • Topical and systemic psoralen plus UVA light – Psoralen is a substance that makes the skin sensitive to UVA light
  • Combination of UVB light and coal tar (Goeckerman therapy)

What are the possible side effects?

Common side effects of phototherapy include:1-3

  • Sunburn or tender skin
  • Burning and stinging
  • Skin dryness
  • Itching

Less common side effects may include:2

  • Blistering
  • Increased facial hair
  • Increased frequency of cold sores
  • Inflammation of hair follicles
  • Inflammation of skin
  • New round or oval flat spots that may be darker than freckles (lentigines)
  • Separation of the nail plate from the nail bed (on fingers or toes)

Using phototherapy over long periods may lead to an increased risk of skin cancer, including melanoma. If UVA treatment is used, it also may contribute to cataracts in the eye.1-3

These are not all the possible side effects of phototherapy. Talk to your doctor about what to expect when receiving phototherapy. You also should call your doctor if you have any changes that concern you when receiving phototherapy.

Other things to know

NB-UVB is the most common type of light used to treat atopic dermatitis. It is safe for adults and adolescents with moderate to severe atopic dermatitis. Your doctor may also prescribe phototherapy using UVA, or a combination of UVA and UVB lights.1-3

Your doctor will decide the type of light, the amount of light (dosage), and the frequency of treatments you need. Factors that will affect this decision include:2

  • How you respond to initial light types and doses
  • Your skin type
  • Local availability of light therapy
  • Cost
  • Topical or oral medicines you are taking that may interact with light therapy (such as calcineurin inhibitors)

Phototherapy should not be used for infants or very young children.3

Before beginning treatment for eczema, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.

By providing your email address, you are agreeing to our privacy policy.

Treatment results and side effects can vary from person to person. This treatment information is not meant to replace professional medical advice. Talk to your doctor about what to expect before starting and while taking any treatment.