Pravit Asawanonda

Wood’s light in dermatology

Wood’s lampwas invented in 1903 by a Baltimore physicist, Robert W. Wood (1868–1955).1 The familiar long-wave ultraviolet (UV) light, known as Wood’s lamp, has become an invaluable tool in the practice of medicine. The first reported use of this lamp in dermatology occurred in 1925, being recommended for the detection of fungal infection of the hair.2 Unlike many other medical devices, which have tended to lose their popularity over time, Wood’s lamp has maintained its usefulness not only in dermatology, but also in ceramics where it can be used to determine repairs.

Transdermal penetration of UV filters.

A penetration study of 2-ethylhexyl-4-methoxycinnamate (EHMC), 4-methyl benzylidenecamphor (MBC), butyl methoxydibenzoylmethane (BMBM), 2-ethylhexyl-2,4,5-trimethoxycinnamate (EHTMC) and di(2-ethylhexyl)-2,4,5-trimethoxybenzalmalonate (TMB) through baby mouse skin (Mus musculus Linn.) was carried out using a vertical Franz diffusion cell. At 4.4 mg/cm2 coverage of UV filter on the skin, 2.98 ± 0.38, 1.15 ± 0.14 and 0.80 ± 0.28% of the applied EHMC, MBC and BMBM were detected in the receptor fluid at 24 h after application. Penetrations of UV filter in an ethanolic solution and lotion forms were comparable. EHTMC and TMB showed insignificant penetration across the baby mouse skins. Baby mouse skins kept at 4, –20 and –80°C gave similar EHMC penetration results. Penetrations of EHMC, BMBM, EHTMC and TMB across human epidermis were carried out upon 5 volunteers using the suction blister technique. The results also confirmed the significant penetrations of EHMC and BMBM and the insignificant penetrations of EHTMC and TMB.

Targeted broadband ultraviolet b phototherapy produces similar responses to targeted narrowband ultraviolet B phototherapy for vitiligo: a randomized, double-blind study.

UNLABELLED Narrowband ultraviolet B (NB-UVB) phototherapy, with a 308-nm xenon chloride excimer laser, and targeted UVB phototherapy have produced encouraging therapeutic results for vitiligo. However, very few studies employing broadband UVB exist. Moreover, there has been no direct comparison study between broadband UVB and NB-UVB for the treatment of vitiligo. The aims of this study were to compare the repigmenting efficacy of targeted broadband UVB phototherapy with that of NB-UVB in an equi-erythemogenic manner. Twenty identical vitiliginous lesions from 10 patients were randomly allocated to receive either targeted broadband UVB or targeted NB-UVB phototherapy. UV fluences were started at 50% of the minimal erythema dose detected within the vitiliginous patches, then increased gradually, in the same manner, to ensure equi-erythemogenic comparison. Treatments were carried out twice weekly for 12 weeks. The results show that grade 1, i.e. 1-25% repigmentation, to grade 2, 26-50% repigmentation, occurred in 6 of 10 subjects. Responses in terms of repigmentation, de-pigmentation, or lack thereof, were similar between lesions receiving broadband and NB-UVB phototherapy. Onset of repigmentation occurred as early as 4 weeks of treatment in most subjects. Treatments were well tolerated, with only minimal erythema and hyperpigmentation. LIMITATIONS The study was carried out in a small number of patients with skin types III, IV and V. The irradiation device was a targeted UVB device and thus the results may not be applicable to other light sources, such as the excimer laser or total-body irradiation cabinets. In conclusion, targeted broadband UVB produces similar clinical responses to targeted NB-UVB in the treatment of the non-segmental type of vitiligo.

8-methoxypsoralen cream plus targeted narrowband ultraviolet B for psoriasis

Background: Targeted ultraviolet (UV) phototherapy is a recent addition to the therapeutic armamentarium for the treatment of localized psoriasis. Topical psoralens enhance the therapeutic effects of UV‐based treatment for various dermatoses, but have never been used in conjunction with targeted UVB.

Topical 8‐methoxypsoralen enhances the therapeutic results of targeted narrowband ultraviolet B phototherapy for plaque‐type psoriasis

Targeted broadband ultraviolet B (UVB) phototherapy as well as 308‐nm excimer laser have been reported to significantly improve or clear localized psoriatic plaques within 5 to 10 treatments when medium fluences [i.e. 4–6 multiples of minimal erythema doses (MED)] were used. Our study was conducted to determine the effects of different concentrations of topical 8‐methoxypsoralen (8‐MOP) cream when used in combination with targeted UV phototherapy with regard to number of treatments and cumulative UV doses to clear localized psoriasis. Ten evaluable patients with stable plaque‐type psoriasis completed the study. Three different concentrations of 8‐MOP creams (0.001%, 0.01% and 0.1%) were applied prior to irradiation with 4 MEDs of targeted narrowband UVB (NB‐UVB), whereas 0.001% 8‐MOP cream was used in conjunction with 5 J/cm2 UVA. All irradiations took place once weekly for 12 weeks. Psoriasis severity index (PSI) score was used to evaluate the efficacy of the treatment. With area‐under‐the‐curve analysis, 0.1% 8‐MOP/NB‐UVB was superior to other modalities in reducing the PSI scores. The number of treatments and cumulative NB‐UVB doses necessary to achieve PSI‐95, a 95% reduction in the scores, was also lower in the 0.1% 8‐MOP/NB‐UVB group, although the differences were not statistically significant. We conclude that topical 8‐MOP cream enhances the therapeutic effects of targeted NB‐UVB phototherapy without significantly increasing the short‐term adverse effects.

Glutathione as an oral whitening agent: a randomized, double-blind, placebo-controlled study.

Abstract Objective: To determine whether orally administered glutathione, 500 mg per day for 4 weeks, affects the skin melanin index, when compared with placebo. Methods: This randomized, double-blind, two-arm, placebo-controlled study was set in the King Chulalongkorn Memorial Hospital, Bangkok, Thailand, a teaching hospital affiliated with a medical school. Sixty otherwise healthy medical students were randomized to receive either glutathione capsules, 500 mg/day in two divided doses, or placebo for 4 weeks. The main outcome was mean reduction of melanin indices measured at six different sites. Several secondary outcomes, including UV spots, were recorded by VISIA™. Efficacies of glutathione and placebo were compared by ANCOVA with baseline values as co-variates. Results: Sixty participants enrolled and completed the study. At 4 weeks, the melanin indices decreased consistently at all six sites in subjects who received glutathione. The reductions were statistically significantly greater than those receiving placebo at two sites, namely the right side of the face and the sun-exposed left forearm (p-values = 0.021 and 0.036, respectively). This was similarly reflected in the changes in the number of UV spots, as measured by VISIA. Both glutathione and placebo were very well tolerated. Conclusion: Oral glutathione administration results in a lightening of skin color in a small number of subjects. However, long-term safety has not been established and warrants more extensive clinical trials.

Treatment of localized vitiligo with targeted broadband UVB phototherapy: a pilot study

Background: Narrowband ultraviolet B (UVB) phototherapy and 308 nm excimer laser have produced encouraging therapeutic results for vitiligo. Repigmentation of various degrees was obtained in different studies.

Association of the interleukin‐10 distal promoter (‐2763A/C) polymorphism with late‐onset psoriasis

Polymorphisms of the IL‐10 promoter have been implicated in the genetic susceptibility to many autoimmune diseases, including psoriasis. Four putative functional single‐nucleotide polymorphisms (SNPs) within the interleukin‐10 promoter region (−3575T/A, −2763A/C, −1082G/A and −592C/A) were analysed in 139 patients with chronic plaque psoriasis and in 155 unrelated healthy controls from Thailand. There were no significant differences in the allele frequencies of any of the four SNPs between patients with psoriasis and controls. However, the frequency of the −2763A allele was increased in patients with late‐onset psoriasis compared with controls and patients with early‐onset psoriasis [OR = 2.94, 95% CI 1.16–7.39, corrected P value (Pc) = 0.04 and OR = 3.26, 95% CI 1.13–9.51, Pc = 0.048, respectively]. The AAGC (−3575/−2763/−1082/−592) haplotype frequency was higher in late‐onset compared with early onset psoriasis (OR = 4.37, 95% CI 1.24–15.97, Pc = 0.027). This study suggests that the −2763A allele and the extended AAGC haplotype can be used as a genetic marker for susceptibility to late‐onset psoriasis in a Thai population.

The use of dihydroxyacetone for photoprotection in variegate porphyria

A 33‐year‐old woman presented with complaints of facial scarring, blisters on the dorsal hands, skin fragility, and increased hair growth on the temples. She reported that these “scratch marks” had appeared spontaneously for 3 years. She was otherwise healthy and not on any medication.

Recommendations for a patient-centered approach to the assessment and treatment of scalp psoriasis: a consensus statement from the Asia Scalp Psoriasis Study Group

Background: International consensus statements on the management of scalp psoriasis are available, but no such recommendations exist for Asia. Methods: The Asia Scalp Psoriasis Study Group (ASPSG) met in May 2011 to review the epidemiologic pattern of scalp psoriasis in Southeast Asia and to develop Asia-specific recommendations for its management. Results: The overall prevalence of psoriasis in Asia is <0.3%, but 75–90% have scalp involvement, whether isolated or with lesions elsewhere, which can negatively impact quality of life (QoL). Treatment decisions should be based primarily on objective disease severity, but should also take account of patient QoL. Psychosocial support and more aggressive treatment should be offered to all patients with moderate to severe QoL impairment. Topical therapy is indicated first-line in all patients, with combination therapy (corticosteroid + calcipotriol), more occlusive formulations, keratolytics, and very potent corticosteroids for patients needing greater or faster efficacy. Systemic therapies, light or laser treatments should be reserved for patients with severe and recalcitrant disease. Conclusions: The ASPSG recommends a patient-centered approach to scalp psoriasis management, consistent with the international consensus statements. Asian physicians should also consider patient QoL, prior treatment response, formulation preferences, likely adherence, cost, time available for self-management, and potential adverse events.