What is the best ultraviolet (UV) light therapy?

Best UV Light Therapy

Narrowband UVB (NB-UVB) is the best first-line UV light therapy for most dermatologic conditions, with PUVA reserved as second-line treatment when NB-UVB fails or for specific indications like plaque-stage cutaneous T-cell lymphoma.

Primary Recommendation: Narrowband UVB (NB-UVB)

NB-UVB should be the initial phototherapy choice for the majority of inflammatory and pigmentary skin disorders based on its superior safety profile and comparable or better efficacy compared to other UV modalities 1, 2.

Conditions Where NB-UVB is First-Line:

• Psoriasis: NB-UVB demonstrates good evidence for efficacy with strength of recommendation A and quality of evidence I 1

• Chronic atopic dermatitis: Good evidence supports NB-UVB as first-line therapy (strength of recommendation A; quality of evidence I) 1

• Vitiligo: NB-UVB is at least as effective as PUVA and produces better color matching to normal skin 1. NB-UVB is more effective in inducing repigmentation in unstable vitiligo than PUVA 1

• Patch-stage cutaneous T-cell lymphoma (CTCL): NB-UVB is as effective as PUVA and is the treatment of choice 1

• Polymorphic light eruption (PLE): NB-UVB shows equivalent efficacy to PUVA for desensitization 1

• Seborrheic dermatitis: NB-UVB has demonstrated effectiveness in open prospective studies 1, 2

When to Use PUVA Instead

PUVA should be considered as second-line therapy when NB-UVB has not been adequately effective, with specific exceptions 1:

PUVA as First-Line:

• Plaque-stage CTCL/mycosis fungoides: PUVA is the first-line treatment (strength of recommendation B) 1

• Especially thick and/or extensive plaque psoriasis: PUVA may occasionally be appropriate as first-line, though NB-UVB should usually be tried first (strength of recommendation B) 1

PUVA as Second-Line (After NB-UVB Failure):

• Widespread vitiligo: PUVA should only be considered if NB-UVB has not shown adequate effectiveness (strength of recommendation A; level of evidence 1+) 1

• Chronic plaque psoriasis: PUVA should be considered before biological therapy but after NB-UVB failure (strength of recommendation B) 1

• Atopic eczema: PUVA should only be considered if NB-UVB has not been adequately effective (strength of recommendation D) 1

• Polymorphic light eruption: PUVA should be considered if UVB has failed or previously triggered the eruption 1

Key Safety Advantages of NB-UVB

NB-UVB has a more favorable safety profile compared to PUVA:

• No requirement for psoralen photosensitization, avoiding systemic medication side effects 1, 2

• Lower long-term carcinogenic risk compared to PUVA 1, 2

• Better tolerated with fewer gastrointestinal side effects (no nausea from oral psoralens) 2

• Can be used more safely in children and during pregnancy 2

Common Pitfalls to Avoid

Do not use PUVA as first-line therapy without attempting NB-UVB first, except for plaque-stage CTCL or occasionally for very thick/extensive psoriasis 1

Avoid broadband UVB (BB-UVB) when NB-UVB is available, as NB-UVB is equally effective or more effective with better tolerability 2, 3

Do not combine psoralen with NB-UVB due to concerns about potential carcinogenicity from producing multiple types of DNA photoproducts 1

Treatment Algorithm

1. Start with NB-UVB for most inflammatory dermatoses, vitiligo, and patch-stage CTCL 1, 2

2. Switch to PUVA if NB-UVB shows inadequate response after an appropriate trial 1

3. Use PUVA first-line only for:

   • Plaque-stage CTCL/mycosis fungoides 1
   • Exceptionally thick/extensive plaque psoriasis (case-by-case basis) 1

4. Consider combination therapy (PUVA with interferon or retinoids) for early-stage mycosis fungoides if monotherapy response is slow 1