Psoriasis PUVA Treatment Can Increase Melanoma Risk
PUVA (psoralen and ultraviolet A radiation) treatment
has been used for decades to treat severe psoriasis. In
this "combination" therapy, the psoralen, taken internally,
acts as a skin sensitizer. The "sensitized" skin affected
by psoriasis can then be treated by ultraviolet A radiation.
Quick GuidePsoriasis Pictures Slideshow: See Moderate to Severe Forms of this Common Skin Condition
What is PUVA?
PUVA is an acronym. The P stands for psoralen, the U for 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 chemicals are energized to interact with DNA, ultimately inhibiting cell multiplication, which is their presumed mode of action.
Certain skin diseases are characterized by cells that are rapidly multiplying. Inhibiting this unrestrained multiplication can be useful in treating these diseases. So PUVA is a combination of an oral drug and subsequent ultraviolet light exposure. The treatment may affect certain blood cells and skin cells so that the skin disease improves.
What diseases does PUVA therapy treat?
One of the skin diseases for which PUVA is used and for which it was originally developed is psoriasis. The psoralen, 8-methoxypsoralen (8-MOP) (Oxsoralen), is used for the treatment of psoriasis along with exposures to ultraviolet light in the UVA spectrum. PUVA is also of benefit in treating vitiligo, mycosis fungoides (cutaneous T-cell lymphoma), and graft versus host disease.
What are the different types of PUVA therapy?
The most common form of therapy combines 8-methoxypsoralen taken by mouth followed 45-60 minutes later by exposure of the skin to UVA. Less commonly, the drug is applied topically (the medication is occasionally diluted in bathtub water in which the patient is immersed) and then after a few minutes the ultraviolet exposure occurs.
Medically Reviewed by a Doctor on 6/9/2015