Narrowband UVB (NB-UVB) phototherapy for psoriasis

Narrowband UVB is medical light therapy given in a treatment booth or panel, under a dermatologist’s supervision. It uses a narrow band of ultraviolet B light, centered close to 311 nanometres. That light slows the overactive growth of skin cells that build up into plaques. It calms an overactive immune response in the skin, and reduces the inflammation behind redness and itch.⌁ Evidence⌁ Evidence

Medical narrowband UVB treats psoriasis in the skin. It does not treat inflammation in the joints and is not a treatment for psoriatic arthritis. It can be used alone, or combined with a topical medicine to work faster. In one study, adding a topical vitamin D analogue reached target plaque clearance in 93.3% of participants by 12 weeks. In another, adding a topical retinoid cut the average time to clearance to about 32 days.⌁ Evidence⌁ Evidence⌁ Evidence

Your dermatologist sets how often you go and adjusts that schedule as you respond. The 2019 joint AAD-NPF phototherapy guideline notes that a more frequent schedule clears psoriasis faster than a less frequent one many patients prefer. The comparison: a mean of 58 days to clear versus 88 days on the less frequent schedule. Most people need regular sessions across several weeks, and your dermatologist typically checks your response after the first several treatments. In a systematic review pooling nine studies, 70.5% of participants reached PASI75, meaning at least a 75% improvement in their psoriasis severity score.⌁ Evidence⌁ Evidence⌁ Evidence

The most common reaction is sunburn-like: redness, tenderness, mild stinging or burning after a session. Dark spots can appear where you were treated, more often with medium-to-dark skin tones. Itching can happen too. Blisters and true burns are uncommon but possible, especially if a dose runs ahead of what your skin tolerates. Over years of treatment, treated skin can age faster, and the added ultraviolet exposure raises long-term skin cancer risk. That is why your dermatologist matches your dose to your skin type and raises it gradually. Call your dermatologist about a reaction that does not fade quickly, a blister, or pain.⌁ Evidence⌁ Evidence⌁ Evidence

People I have heard from are weighing a clinic course against a home unit. A 2026 economic model simulated adults with moderate-to-severe plaque psoriasis. It found a mean annual out-of-pocket cost of $5,004 for office-based phototherapy, against $1,450 for a home NB-UVB unit. Mean total annual cost, patient and payer combined, was $14,760 for office-based care versus $6,222 at home. These are simulated averages for a modeled population, not a personal quote. Your real cost depends on your own plan, copay, deductible, and how many sessions you need.⌁ Evidence

No reader has sent me a first-hand account of NB-UVB phototherapy for psoriasis yet. Until someone does, here is what the label and the studies say about living with it.⌁ Evidence

Keep a simple, dated record of which sessions you attend each week. Add a same-conditions photo (same light, distance, and angle) around your four-to-six-treatment check-in, then again at any later review your dermatologist sets. If you switch between office visits and a home device, note the date of the switch. Your dermatologist will want to recalibrate rather than assume continuity.⌁ Evidence⌁ Evidence