Healthy Participants and/or Patients Clinical Trial
Official title:
Comparing Minimal Erythema Dose (MED) in UVB Devices in the Presence and Absence of UV Filter
Psoriasis affects 2-3% of the American population. While a wide variety of therapies currently exist, including topical corticosteroids and Vit D analogs, oral immunosuppressant and retinoid agents a better understanding of phototherapy is needed. Given the prevalence of localized psoriasis and dissatisfaction with treatment, investigation of localized treatment should be a priority for researchers with goals to improve the current standard of care.
Psoriasis affects 2-3% of the American population. Psoriasis involving less than 10% BSA in
the absence of joint involvement tends to be treated locally. More than 80% of people with
psoriasis have <10% BSA involvement. A wide variety of therapies currently exist, including
topical corticosteroids and Vit D analogs, oral immunosuppressant, retinoid agents, and
phototherapy. Given the prevalence of localized psoriasis and dissatisfaction with treatment,
investigation of localized treatment should be a priority for researchers with goals to
improve the current standard of care.
UV light has a wavelength of 10nm - 380nm, which is slightly shorter than the wavelength of
visible light. The UV light can be further classified to a narrow spectrum (UVB light has a
wavelength of 280-315 nm). UVA has a wavelength of 315-400nm. Tanning beds use UV light to
produce their effects. Whole body ultraviolet B (UVB) phototherapy is efficacious and is
recommended as a first line option in selective psoriasis treatment recommendations. In
pregnancy, UVB therapy is recommended as first line treatment for extensive plaque and
guttate psoriasis.
Although UVB phototherapy has been included in the guidelines for psoriasis treatment, its
use does not come without risk. Toxicities include cataract formation, herpes reactivation,
photoaging, and with long-term exposure may lead to an increased risk of genital tumors in
males. In addition, the use of UVB is rarely used as a first-line treatment for localized
psoriasis probably due to financial issues and increased requirements for clinic visits.
Narrowband UVB therapy (emission 311- 313nm) is superior to broad-band UVB light, and reduces
toxicity. Psoriatic plaques can withstand much higher doses of UV light than the surrounding
uninvolved skin; UV treatment of just the involved skin therefore offers increased efficacy
in fewer treatments. In addition, localized treatment may remain in remission even 4 months
after clearing with localized laser treatment. Localized treatment should therefore be a more
favorable treatment option for psoriasis, using higher doses with sparing of healthy skin.
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