1. Phototherapy of psoriasis
Ljubomir B Novaković FRCP
Consultant Dermatologist
QEH and St. John’s Institute of Dermatology, London
The Southeast of England Phototherapy Network
17th Update Meeting, St. Thomas’ Hospital, 19th June 2014

2. Phototherapy
Traditionally means the use of artificial UVB irradiation delivered by fluorescent lamps without the addition of an exogenous photosensitizer
Narrowband UVB (NB–UVB, TL–01)
Broadband UVB (BB–UVB) 2

3. Photochemotherapy with psoralens
Psoralens – naturally occurring phototoxic compounds; absorb photons and go on to interact with cell function via photochemical reactions
PUVA = combined use of the furocoumarin drug psoralen (P) + ultraviolet A (UVA)
Wholebody (oral, bath)
Local (oral, paint, bath)

4. Phototherapy Mechanism of action
UV radiation is absorbed by endogenous chromophores – nuclear DNA
Alteration of the cytokine profile
Promotion of immunosuppression
Cell cycle arrest – induction of apoptosis

5. Phototherapy – safety Dosimetry and calibration
Constancy of lamp output should be checked weekly using an independent hand–held dose meter
Calibration of a UV dosimeter – on an annual basis
BAD Working Party report on minimum standards for phototherapy services (

6. Minimal erythema dose (MED) and minimal phototoxic dose (MPD)
The MED/MPD is the dose that provokes a just perceptible erythema
Establishing MED/MPD – safe practice
Skin type assessment – risk of burning

7. Phototherapy of psoriasis
Moderate to severe psoriasis
Psoriasis unresponsive to topical treatment
“Thick” psoriasis – PUVA or combination therapy with UVB
Children – UVB phototherapy
Standard course – around 30 sessions

8. Phototherapy of psoriasis Protocol for oral PUVA
With MPD testing (preferred)
8–methoxypsoralen (MOP) or 5–MOP
Frequency of treatment: twice per week
Initial dose: 70% MPD
Increments: 20%
Maximum single dose: 15 J/cm²

9. Bath PUVA Bath PUVA preferred to oral PUVA:
in children
significant hepatic dysfunction
in patients with cataracts
where psoralen–drug interaction anticipated i.e. warfarin
No need for eye protection after therapy
Lack of systemic side effects e.g. nausea

10. Phototherapy of psoriasis Protocol for bath PUVA
With MPD testing (preferred)
8–MOP preferred to 5–MOP and TMP (increased risk of a blistering phototoxic reaction)
Frequency of treatment: twice per week
Initial dose: 50% MPD
Increments: 20%
Maximum single dose: 8 J/cm²

11. Hand and foot PUVA Frequency of treatment: twice per week
Maximum single dose: 15 J/cm²

12. Phototherapy of psoriasis Protocol for NB–UVB
With MED testing (preferred)
Frequency of treatment: three times per week (preferred)
Initial dose: 70% of MED
Increments: 20%
Maximum single dose: 5 J/cm²

13. Psoriasis NB–UVB is superior to BB-UVB
Almost 30 years of clinical experience and data from several controlled studies have demonstrated that NB–UVB is more effective for psoriasis than NB–UVB

14. Randomized double–blind trial of the treatment of chronic plaque psoriasis: efficacy of PUVA vs NB–UVB therapy
PUVA is significantly more effective than NB–UVB, requiring significantly fewer treatments for clearance, giving significantly longer remissions, and having a similar low incidence of short–term adverse effects
However, because of better long–term safety of NB–UVB than PUVA, it should be preferred as a first choice, until disease response noted, PUVA being kept in reserve for NB–UVB failures
Yones SS et al. Arch Dermatol 2006; 142(7): 836–42.

15. Median treatment numbers for clearance with PUVA and NB–UVB
PUVA is significantly more effective than NB–UVB requiring significantly fewer treatments for clearance (PUVA median = 17, NB–UVB median = 28.5, p<0.001)

16. PUVA and NB–UVB are both effective
Efficacy of PUVA therapy vs NB–UVB in chronic plaque psoriasis: a systematic literature review
PUVA and NB–UVB are both effective
PUVA tends to clear psoriasis more reliably, with fewer sessions, and provides with longer lasting clearance
NB–UVB is preferred as first line phototherapy option because of long–term risks of PUVA
Archier E et al.. J Eur Acad Dermatol Venereol 2012; 26 (Suppl 3):

17. Phototherapy of psoriasis Minimising a risk
Keep cumulative doses low
Do not exceed a total number of sessions over 150 for PUVA and 200–300 for NB–UVB
Combination therapy e.g. retinoids
Regularly update and improve protocols; audit
Life–long monitoring of patients who received excessive PUVA

18. Combination therapy
Topicals: tar, dithranol, calcipotriol, tazarotene; corticosteroids
Retinoids (Re–PUVA, Re–NB UVB)
Methotrexate
Biologics – main concern is potentially increased risk of skin cancer

19. Acute side effects of phototherapy
Similar to sunburn
Clinical features: erythema, edema, vesiculation and necrosis
Peak before 24 hours – UVB
Peak at about 72–96 hours – PUVA, related to psoralen phototoxicity
More likely with topical PUVA
Oral 8–MOP may cause nausea/vomiting
Some patients may develop PLE

20. Long–term side effects of phototherapy
UVB is known carcinogen
No significant association between NB–UVB and BCC, SCC or melanoma in 3867 patients treated with NB–UVB in Tayside, Scotland
However, cautious interpretation is required – relatively few patients who had a high treatment number and because the slow evolution of skin cancers may result in a delayed incidence peak
Hearn RM et al. Br J Dermatol 2008; 159: 931–5 .

21. Long–term side effects of PUVA
Premature photoageing
Risk of cataracts
PUVA lentigines
Increased number of actinic keratoses
SCC incidence in PUVA–treated psoriasis correlates with cumulative UVA dose
Slightly increased risk of melanoma (Stern RS and the PUVA Follow-Up Study, 2001); cumulative dose or number of phototoxic episodes

22. Phototherapy of psoriasis Conclusion
Phototherapy, in its different forms has proved itself to be well–established, safe, effective and reliable in the treatment of psoriasis
NB–UVB should be preferred as a first choice because of better long–term safety
PUVA is more effective than NB–UVB
Combination with other treatment modalities should be considered in unresponsive patients
Phototherapy will remain a cornerstone in the treatment of psoriasis