Minimal Phototoxic Dose for Vitiliginous Skin Lesions / 대한피부과학회지

BACKGROUND: Photochemotherapy (PUVA) is the effective treatment for vitiligo. It is necessary to measure the minimal phototoxic dose (MPD) in order to ascertain a safe, effective UVA dose needed for irradiation during photochemotherapy. OBJECTIVE: The purpose of this study was to standardize the MPD for vitiliginous lesions. METHOD: The MPD was measured in 124 vitiligo patients. The number of patients monitored for topical and systemic MPD using the photosensitiser, 8-methoxypsoralen (8-MOP) were 41 and 83, respectively. MPD was also analysed according to sex, age, site of the vitiliginous lesions, duration of disease, season and administration route of the photosensitiser. RESULTS: 1. In the group assessed for topical application of 8-MOP cream, mean MPD was 0.62+/-0.59J/cm2. 2. In the group assessed for systemic administration of 8-MOP, mean MPD was 2.68+/-1.83J/cm2. 3. MPD in the group systemically administrated with 8-MOP was 4.32-fold to that of the topical application group (p<0.01). 4. In the case of both topical and systemic administration of the photosensitiser, 8-MOP, no significant differences in MPD were found due to the sex, age, site of vitiliginous lesions, duration of disease, or season in which MPD was administered to patients. CONCLUSION: There was a significant difference in MPD between the topical application group and the systemic administration group.

Response of PUVA Therapy in Vitiligo Patients / 대한피부과학회지

BACKGROUND: Psoralen and UVA(PUVA) are the most common and effective treatments for vitiligo. UVA treatment requires measurement of the minimal phototoxic dose (MPD) in order to determine adequate UVA irradiation for safe and effective photochemotherapy. There have been only a few reports about the efficacy of PUVA therapy in which the exposure dose was determined by the MPD. OBJECTIVE: The purpose of this study was to measure the MPD on vitiliginous lesions and to evaluate the response of vitiligo patients to photochemotherapy. METHODS: The minimal phototoxic dose of UVA was measured in 82 vitiligo patients. Thirty two of the 82 patients were treated by PUVA therapy for at least three months. The initial exposure dose was two thirds of the MPD. Subsequently we evaluated the initial exposure dose, the total exposure dose, and the total number of exposures until initial repigmentation appeared. Adverse effects of PUVA therapy were also evaluated. RESULTS: 1. The initial repigmentation rate for systemic PUVA therapy was highest for the trunk (68.4%), followed by the face and neck (33.3%), and the extremities(6.3%). 2. For topical PUVA treatment the mean total exposure dose was 2.3J/cm2, the number of treatments was 5.3, and the duration until initial repigmentaion appeared was 16.5 days. In the case of systemic PUVA treatment the same parameters were 12.0J/cm2, 7.1, 27.3 days, respectively. 3. In the systemic PUVA therapy group the total exposure dose was 21.4+/-15.0J/cm2 for patients with lesions of less than one year duration and 8.7+/-5.1J/cm2 for patients with lesions of longer than one year duration. 4. The adverse effects of topical PUVA therapy were erythema (7 of 11 cases), prickling (3 of 11 cases), pruritus (2 of 11 cases), and desquamation (1 of 11 cases). 5. Side effects in 23 patients with systemic PUVA therapy were erythema (78.3%), pruritus (47.8%), gastrointestinal symptoms (21%), burn (8.7%), and headache (1.9%). There were no side effects in topical and systemic PUVA therapy as much as PUVA therapy discontinued. Conclusion : These results indicate that PUVA therapy in cases where the initial exposure dose is determined by MPD, subsequently the exposure dose is determined by visual inspection of vitiliginous lesions and history taking of subjective symptoms on each treatment is safe and effective.

Minimal Phototoxic Dose for a Vitiliginous Skin Lesion / 대한피부과학회지

BACKGROUND: It is mandatory to measure the minimal phototoxic dose(MPD) in order to determine adequate irradiation of UV-A in photochemotherapy. However, the measurement of MPD is not easy in some cases due to inadequte size and site of lesions, time and manpower. OBJECTIVE: The purspose of this study was to standardize the minimal phototoxic dose for a vitiliginous lesion. METHODS: The minimal phototoxic dose of UV-A was measured in 82 vitiligo patients. Then we analyzed the MPD according to the sex, age, site of the vitiliginous lesions, duration of disease, and administration route of the photosensitizer. RESULTS: 1. There were no significant differences between exposed and unexposed areas in MPD in both cases of topical and systemic administration of the photosensitiser. 2. There was no significant correlation between disease duration and MPD in both cases of topical and systemic administration of the photosensitiser. 3. In the group of topical application of 8-methoxypsoralen cream, MPD for males and females were 0.53+0.38J/cm2 and 0.48+0.32J/cm2 respectively without significant difference in sex. 4. In the group of systemic administration of 8-methoxypsoralen, there was a significant difference between males and females in MPD. The MPD in males and females were 1.38+0.72J/cm2 and 2.51 + 1.40J/cm2, respectively. 5. In the group of topical application of 8-methoxypsoralen cream, the MPD in 2nd decade patients was the highest(0.80+0.55J/cm2). The MPD had a tendency to decrease gradually as age receded from the 2nd decade. 6. In the group of systemic administration of 8-methoxypsoralen, there was a tendency for the MPD to be increased according to age without statistical significance. 7. MPD in the group systemically administrated with 8-methoxypsoaralen was four-fold to that of the topical application group. CONCLUSION: It may be valuable to keep in mind that there was a statistical differrence in MPD between sexes in systemic administration of the photosensitizer, and that MPD was different according to patients age in the topical application group.

Study of the Minimal Erythema Dose and Minimal Melanogenic Dose of UVA - 1 and Minimal Phototoxic Dose of UVA - 1 and UVA - 2 in Young Adult Koreans / 대한피부과학회지

BACKGROUND: Minimal erythema dose(MED), minimal melanogenic dose (MMD) and minimal phototoxic dose(MPD) of UVA-1 in Koreans has not been determined, although MED and MMD of UVB and MPD of UVA-2 in Koreans have been reported. OBJECTIVE: This study was done to measure the MED and MMDs including minimal immediate tanning dose(MITD) and minimal delayed tanning dose(MDTD) of UVA-1 radiation and compare the MPD of UVA-1 with that of UVA-2. METHODS: In this study, a metal halide lamp (SUPUVASUN 3000) and a fluorescent blacklight lamp (Philips TL 20W/09N UVA lamp) were used as the UVA-1 and UVA-2 light sources, respectively. After the determining of Fitzpatrick's skin phototypes, the back skins of young adults were irradiated and the MED, MITD and MDTD of UVA-1 were assessed at 24 hours, 1 hour, and 7 days after irradiation, respectively. The minimal doses of phototoxic reaction, which was induced by oral 8-MOP plus UVA-1 or UVA-2, were assessed visually 72 hours after irradiation. RESULTS: MED,was 61.20+/-11.50J/cm(mean+S.D.). MITD and MDTD of UVA-1 were 48.00+/-8.57J/cm and 65.30+/-12.10J/cm respectively. MPDs of UVA-1 and UVA-2 were 14.88+/-3.88J/cm and 4.40+/-1.69J/cm, respectively. CONCLUSION: In this study, the MED and MMD of UVA-1 radiation and the MPD of UVA-1 and UVA-2 radiation were measured in young adult Koreans. The MITD was less than the MED, and the MDTD was almost the same as the MED. The MPD of UVA-1 was three times higher than that of UVA-2. There vere no significant correlations between the MEDs, MMDs or MPDs and the skin phototypes.

Study of the Minimal Erythema Dose and Minimal Melanogenic Dose of UVA - 1 and Minimal Phototoxic Dose of UVA - 1 and UVA - 2 in Young Adult Koreans / 대한피부과학회지

BACKGROUND: Minimal erythema dose(MED), minimal melanogenic dose (MMD) and minimal phototoxic dose(MPD) of UVA-1 in Koreans has not been determined, although MED and MMD of UVB and MPD of UVA-2 in Koreans have been reported. OBJECTIVE: This study was done to measure the MED and MMDs including minimal immediate tanning dose(MITD) and minimal delayed tanning dose(MDTD) of UVA-1 radiation and compare the MPD of UVA-1 with that of UVA-2. METHODS: In this study, a metal halide lamp (SUPUVASUN 3000) and a fluorescent blacklight lamp (Philips TL 20W/09N UVA lamp) were used as the UVA-1 and UVA-2 light sources, respectively. After the determining of Fitzpatrick's skin phototypes, the back skins of young adults were irradiated and the MED, MITD and MDTD of UVA-1 were assessed at 24 hours, 1 hour, and 7 days after irradiation, respectively. The minimal doses of phototoxic reaction, which was induced by oral 8-MOP plus UVA-1 or UVA-2, were assessed visually 72 hours after irradiation. RESULTS: MED,was 61.20+/-11.50J/cm(mean+S.D.). MITD and MDTD of UVA-1 were 48.00+/-8.57J/cm and 65.30+/-12.10J/cm respectively. MPDs of UVA-1 and UVA-2 were 14.88+/-3.88J/cm and 4.40+/-1.69J/cm, respectively. CONCLUSION: In this study, the MED and MMD of UVA-1 radiation and the MPD of UVA-1 and UVA-2 radiation were measured in young adult Koreans. The MITD was less than the MED, and the MDTD was almost the same as the MED. The MPD of UVA-1 was three times higher than that of UVA-2. There vere no significant correlations between the MEDs, MMDs or MPDs and the skin phototypes.

A Study on the Minimal Phototoxic Dose (MPD) / 대한피부과학회지

In order to measure the MPD with 8-methoxypsoralen, we selected 49 Korean healthy male vlunteers without phototoxic or photosensitive dermatoses. They were divided to 3 groups (Immediate; group 1, 1 hour; group 2, 2 hours', group 3) according to the waiting time, intervals of application of photosensitizer a,nd UVA:irradiation. The reaults were summarized as follows: 1. MPDs of group 1 had no clinical significance. 2, MPDs of group 2 were more than those of group '3 independently of application methods of photosensitizer. 3. In the cases of topical application of 8-MOP, MPDs of group 3 according to reading interval (24 hours, 48 hours and 72 hours after UVA irradiation) were 3.4+/-2.9 J/cm2, 1.9+/-l.5 J/cm' and l. 7+1, 2/cm, respectively. 4 In the cases of oral administration of 8-MOP, MPDs of group 3 according to reading; interval as topical application of 8-MOP were 7.1+/-2.3 J/cm, 4.4+/-1.1 J/ cm2 and 4.2+/-l.2 J/cm2, respectively. 5 MPL)s accarding to the skin types as follows; (waiting time; 2 hours, read- ing interval; 48 hours) a. In the case of topical application of 8-MOP, MPDs of the skin type ]II, 1V and V were 0.9+/-0.5 J/cm2, 1.8+/-1.1 J/cm2 and 3.0+/-l.3 J/cm2 respectively. b. In the case of oral administration of 8-MOP, MPDs of skin type g, W and were 3.5+/-1.1 J/cm2, 4.7+/-1.3 J/cm2 and 6.9+/-l.8 J/cm2, respectively.