Efficacy of topical vitamin C derivative (VC-PMG) and topical vitamin E in prevention and treatment of UVA suntan skin.

Exposure to ultraviolet radiation is known to cause many adverse side effects by inducing the tissue to produce reactive oxygen species. By inhibiting these mediators, administration ofantioxidants might be the strategy to reduce UVA-induced skin reaction such as tissue damage and inflammation. However the present study showed that administration of topical 10% vitamin C derivative (VC-PMG) and topical 5% vitamin E has no effect in terms ofprevention or treatment of UVA suntan skin in 20 volunteers. Prior to 30 Joules UVA exposures, they were asked to apply both agents twice daily for 3 days. Then, the melanin index was measured immediately after irradiation by using the Maxemeter which was insignificant at the 95% level of confidence compared with the placebo. After continuing the cream application for 12 weeks, there were also no bleaching effects observed after 2, 4, 6, 8, 10 and 12 weeks compared to the placebo.

Result of standard patch test in patients suspected of having allergic contact dermatitis.

Contact dermatitis is a common skin disease. Disease was diagnosed by a history of contact substance together with geographic distribution of lesion. Up till now, standard patch test is one of the most reliable test to identify and confirm causative agent of allergic contact dermatitis. To determine the rate of positive standard patch test and to identify the common allergen of contact dermatitis in Thailand, we performed the standard patch test in 129 patients, suspected having allergic contact dermatitis at Department of Dermatology, King Chulalongkorn Memorial Hospital, Thailand from June 1, 2003 to September 1, 2004. The rate of positive standard patch test is 59.7% (n = 77/129). The most 3 common positive allergens were nickel sulfate (18.60%), cobalt chloride (17.05%) and fragrance mix (14.73%), respectively. The chance of positive standard patch test significantly correlated with sex (woman), initial diagnosis as contact dermatitis and history of house-worker (p = 0.017, p = 0.005 and p = 0.023, respectively). Whereas, there were no significant correlation between the chance of positive standard patch test and age of patient, location of lesion, history of recurrence, history of atopy, history of drug and food allergy. In addition, history of metal allergy significantly correlated with the chance of positive nickel sulfate or cobalt chloride in standard patch test (p = 0.017). In conclusion, this study demonstrated the prevalence of causative allergen of contact dermatitis in Thai patients using that standard patch test. Moreover, our data shown that the chance positive standard patch test was greater in patient, who were women or initial diagnosed as contact dermatitis or had history of houseworker or history of metal allergy.

Efficacy of aloe vera cream in prevention and treatment of sunburn and suntan.

The efficacy of aloe vera cream in prevention of burn and tan from ultraviolet were studied in 20 volunteers. The minimal erythema dose of 20 volunteers were tested. The mean MED was 40-60 mj. The well preserved containing 70% of aloe vera cream. The aloe vera cream was applied randomized double blind technique on the test sites 30 minutes before, immediately after, or both before and after then the serial ultraviolet UVB 40,50,60,70,80 mj were radiated. MED reading at 24 hour for sunburn evaluation. Erythema and pigmentation were evaluated by visual grading 1-4 score. The aloe vera cream was continuing applied at the test sites twice daily for the the next three weeks. The results showed that the aloe vera cream has no sunburn or suntan protection and no efficacy in sunburn treatment when compared to placebo. The aloe vera cream has no bleaching effect too.