PUVA is an acronym. The P stands for psoralen, the U for an ultra, the V for violet, and the A for that portion of the solar spectrum between 320 and 400 nanometers in wavelength. Psoralens are chemicals found in certain plants that have the ability to absorb ultraviolet light in the UVA portion of the solar spectrum. Once the light energy is absorbed, these psoralens are energized to interact with DNA, ultimately inhibiting cell multiplication, which is its presumed mode of action.
Certain skin diseases are characterized by cells that are rapidly multiplying. Inhibiting this unrestrained proliferation can be useful in treating these diseases. So PUVA is a combination of an oral drug and subsequent ultraviolet light exposure
How is Photochemotherapy used in the treatment of psoriasis?
Psoriasis is a common skin disease that results in the formation of thick plaques on the skin. PUVA is usually given to those patients who have severe psoriasis or those who do not respond to other treatment options. It is effective in clearing psoriasis in most cases, though it is not a permanent cure. The first few treatments are of short duration (under 3 minutes) and are scheduled twice a week. Depending on the body’s response to the therapy, the frequency and duration of treatment are adjusted. Most patients with psoriasis respond within 6 to 8 weeks, following which the PUVA therapy is then stopped. However, psoriasis may flare-up again after a few months, and PUVA treatment can be repeated.
Can sunlight be used for PUVA therapy?
Sunlight can be used instead of ultraviolet light if facilities to administer the light therapy are not available. However, unlike the ultraviolet light therapy administered in a hospital, the dose of the sunlight cannot be controlled, and it is unpredictable.