Photochemotherapy for Psoriasis / 대한피부과학회지

ABSTRACT

The beneficial effects of sunlight and ultraviolet light for the treatment, of psoriasis vulgaris has long been recognized. Parrish et al were the first to introduce a controlled light source, which allowed the delivery of a known quantity of light energy to the patients skin after the patient had ingested a photosensitizer, 8-methoxypsoralen (methoxsalen) two hours previous to UVA exposure. This successful treatment has become known as PUVA (psoralen and UVA). PUVA photochernotherapy denotes a systemic approach that is based on the interaction of light and a photoactive drug. Parrish et al have described successful treatment of psoriasis with PUVA and other investigators alI over the world have confirmed their beneficial results. The rationale of photochemotherapy in psoriasis is the inhibition of the increased DNA synthesis within the psoriatic lesions by the interaction of psoralen molecule and light energy in the UVA range(320-400nm). The present study was undertaken to evaluate the therapeutic effectiveness of PUVA photochernotherapy combining orally administered methoxsalen and UAA exposure using Dermatron UVA phototherapy system in patients with wi5espread psoriasis. A total of 15 patients with psoriasis over more than 30% of their bodies were selected at the department of dermatology, National Medical Center through March 1978 to September 1978. Oral administration of methoxsalen, 20 to 50 mg doses according to body weight, was followed by exposure to a high-intensity longwave ultraviolet light emitting a continuous spectrum between 320 and 400nm (peak emission, 350 - 365nm). Initial UVA exposure times were based on each patients minimal phototoxicity dose (MPD) and exposure times were increased at each treatment by 1 - 2 minutes to maintain minimal erythema. Frequency of treatment was two to three times weekly. Once the psoriatic lesions had, cleared completely the patient was placed on a maintenance schedule. If psoriasis recurred the frequency of treatment was increased. The results were as follows l. 5 patients were dropped out due to unknown reasons. 2. 7 cases showed clearing of over 95, of the lesions (Response 5'). Mean number of PU VA therapy was 16. 7. During 1 4 months follow-up period, 4 cases remained free of psoriasis but 3 cases couldn't be followed. 3. Immediate side effects of PUVA were temporary and generally mild. No significant changes in laboratory screenings were noted. Side effects of therapy included transient nausea(33.3%), dizziness(26.7%), erythema.(66.7%), pruritus (60%), increased pigrnentation(100 %). 4. Comparison of pre-and post-PUVA therapy in biopsy specimens by light microscopy revealed histologic improvement evidenced by diminished acanthosis and parakeratosis, and regeneration of granular layers in all of 8 cases. Glycogen accumulation in the affected epiderrnis was significantly decreased or absent after PUVA therapy in all cases.