Treatment of psoriasis is step by step:

The base and most important is education and support

Then comes topical treatment

Then comes systemic treatment and/or phototherapy



Does UVB (Ultraviolet type B) have a role to play in the treatment in psoriasis?

US Survey on 387 dermatologists and asked what treatment they would use as first line therapy:

“Healthy adults with 10% BSA (Body Surface Area affected) not working on topicals and health affected”

-UVB was answered as the first line therapy in 40% in men up to 60% in women. The difference is because use of methotrexate and retinoids is risky in women of childbearing age.

-Phototherapy is therefore still the champion for clinicians !



What is the most effective treatment: systemic treatment or phototherapy ?

Study done in 713 patients from 10 medical centers:

…with moderate to severe psoriasis
…on monotherapy (using one treatment)



Out of the patients: the following proportion were “Clear or almost clear” with:

-Methotrexate (MTX): 23.8% of cases

-Adalimumab: in 47.7% of cases

-Ustekimumab and Etanercept in around 30% of cases

-Phototherapy: in 26% of cases.



Phototherapy appears slightly less effective than the other biologics. However, there is a huge cost difference. UVB is cost effective. With one year of treatment with biologics, one can buy one phototherapy machine !



How does phototherapy work in psoriasis?

It is somewhat still speculative

It acts on keratinocyte hyperproliferation and immune activation



UVB action on immune activation:

-Induces apoptosis of activated T cells



-Induction of T-regulatory cells: UVB action on keratinocyte hyperproliferation

  • -UVB radiation on the epidermis induces also apoptosis of epidermal keratinocytes.
  • -On biopsy: staining with caspase-3 is positive and thus shows apoptosis.



Dangers of phototherapy in psoriasis

UVB is a complete carcinogen and causes carcinogenesis in mice at high dosage



However in psoriasis:

-PUVA (psoralen + ultraviolet A) causes 30 times increased incidence of SCC (Squamous Cell Carcinoma) and 5 times more of BCC (Basal Cell Carcinoma):

  • -2/3 of the SCCs are located on the lower limbs
  • -150 and 350 treatments are thresholds for heightened risk of skin cancer
  • -NBUVB (narrowband) is safer as it only uses on wavelength (311nm)



Source of Information: Lui H, Phototherapy Update. Dubai World Dermatology & Laser Conference & Exhibition – Dubai Derma 13 – Dubai, United Arab Emirates (UAE)

Photo credit: wikipedia