Narrowband UVB, which emits a specific wavelength of ultraviolet light at 311 nanometers, is the most effective and widely recommended form of light therapy for eczema. It can reduce eczema severity by up to 90% within 8 to 12 weeks. Other wavelengths, including UVA1 and blue light, have roles in specific situations, while red light therapy remains largely unproven for eczema despite growing consumer interest.
Narrowband UVB: The Standard Treatment
Narrowband UVB (NB-UVB) is the first-line light therapy for moderate to severe eczema. The American Academy of Dermatology conditionally recommends phototherapy for atopic dermatitis, and NB-UVB is the go-to option for most patients. It works by suppressing the overactive immune cells in the skin that drive eczema flares, calming inflammation from the inside out.
Treatment typically involves three sessions per week, with at least 48 hours between each session. Each visit is brief, often just a few minutes of standing in a light booth. A full course continues until the skin clears or stops improving, which for most people takes 8 to 12 weeks. Some patients reach near-complete clearance in that window.
A major concern people have about UV-based therapy is skin cancer risk. A large population-based study following over 6,200 eczema patients for a median of 11 years found that UVB phototherapy did not increase the risk of skin cancer, including both non-melanoma skin cancer and melanoma. Even the total number of sessions a patient received showed no association with increased cancer risk. That said, people with a history of multiple skin cancers or melanoma are generally not good candidates for any UV-based therapy.
UVA1: For Severe or Deep Eczema
UVA1 phototherapy uses longer-wavelength ultraviolet light that penetrates deeper into the skin than UVB. While UVB primarily affects the outer layer, UVA1 reaches the dermis, where it targets immune cells, mast cells, and inflammatory T cells that congregate deeper in the tissue. This makes it particularly useful for thickened, chronic eczema patches where inflammation has settled deep beneath the surface.
UVA1 is less widely available than NB-UVB because the equipment is more specialized and expensive. It tends to be reserved for cases where NB-UVB hasn’t worked well enough or where the eczema is especially severe. It’s not the default starting point, but it fills an important gap for people with stubborn disease.
Blue Light: Promising but Early
Blue light therapy, in the 400 to 500 nanometer range, is generating interest for eczema because it works through a completely different mechanism than UV light. It has anti-inflammatory and antimicrobial properties, which matters for eczema because the skin of people with atopic dermatitis is frequently colonized by bacteria that worsen flares. Blue light can reduce that bacterial burden while also dialing down inflammation.
The advantage of blue light is that it’s not ultraviolet, so it doesn’t carry the same theoretical concerns about DNA damage or photoaging. However, blue light therapy for eczema is still in relatively early stages compared to the decades of evidence behind NB-UVB. It shows up in research as a “promising therapeutic tool” for atopic dermatitis, but it hasn’t yet replaced UV-based phototherapy in clinical guidelines.
Red Light: Limited Evidence for Eczema
Red and near-infrared light therapy (typically 630 to 850 nanometers) is widely marketed through at-home LED devices and face masks. These wavelengths have documented anti-inflammatory effects in skin tissue and may support skin barrier repair. For eczema specifically, though, the evidence is thin. The National Eczema Association notes that while red and near-infrared light have “potential anti-inflammatory and skin barrier-supporting benefits,” there haven’t been enough clinical trials to demonstrate they truly work for eczema.
If red light therapy does help, the expected benefits would be reduced redness, less irritation, and gradual improvement in skin barrier function over time. Results vary significantly between individuals, and LED therapy is not considered a replacement for established eczema treatments. If you’re curious about trying an at-home LED device, treat it as a possible complement to your existing routine rather than a standalone solution.
Home Units vs. Clinic Visits
One of the biggest barriers to phototherapy is getting to a clinic three times a week for months. Home NB-UVB units, which are FDA-cleared for eczema, offer a practical alternative. A large clinical trial comparing home and office-based narrowband UVB found that home treatment was just as effective as in-office sessions. In fact, home users had better quality-of-life scores at 12 weeks, likely because they could stick with the regimen more consistently. Treatment adherence was dramatically higher in the home group: 51.4% compared to just 15.9% for office-based patients.
Home units did produce slightly more episodes of persistent skin redness (5.9% vs. 1.2%), but the devices have built-in dose limits that prevent serious burns. No patients in the study stopped treatment because of redness. Home phototherapy requires a prescription and initial guidance from a dermatologist to set your starting dose and escalation schedule, but once that’s established, the convenience makes it far easier to complete a full course.
Who Should Avoid Light Therapy
Certain conditions rule out phototherapy entirely. Xeroderma pigmentosum, a genetic condition causing extreme UV sensitivity, is an absolute contraindication. Lupus is also incompatible with UV-based light therapy because ultraviolet exposure can trigger flares. People taking immunosuppressive medications like azathioprine or cyclosporine face a significantly elevated risk of skin cancer from phototherapy and should not combine the two.
Several common medications increase your skin’s sensitivity to light and can cause burns or reactions during treatment. These include:
- Certain antibiotics: tetracyclines, fluoroquinolones, and sulfonamides
- Anti-inflammatory drugs: NSAIDs like ibuprofen
- Thiazide diuretics: commonly prescribed for blood pressure
- Retinoids: used for acne and anti-aging
- St. John’s Wort: an herbal supplement for mood
If you take any of these, your dermatologist may still be able to adjust your phototherapy protocol, but it’s essential to disclose everything you’re taking before starting treatment.
Light Therapy for Children With Eczema
Phototherapy is an option for children with moderate to severe eczema who haven’t responded well to topical treatments. The American Academy of Pediatrics states that it should be prescribed and conducted by clinicians experienced with phototherapy equipment. There is no universally defined minimum age, but UVB phototherapy is generally avoided in infants, and PUVA (a different type using a photosensitizing drug plus UVA light) is rarely recommended before adulthood due to long-term cancer risk. For school-age children and adolescents, NB-UVB is the preferred option when light therapy is warranted. Children receiving phototherapy should not be on cyclosporine at the same time.