Validation of a semiautomated method of minimal erythema dose testing for narrowband ultraviolet B phototherapy

Clinical and Spectrophotometric Evaluation of Skin Photoadaptation in Vitiligo Patients after a Short Cycle of NB-UVB Phototherapy

BACKGROUND

The phenomenon of photoadaptation to narrow-band ultraviolet B (NB-UVB) radiation has been previously described in vitiligo and has usually been clinically measured by the assessment of the minimal erythema dose (MED) after phototesting.

OBJECTIVES

To assess the photoadaptive response in vitiligo and healthy skin after NB-UVB phototherapy not only clinically, but also by spectrophotometry.

MATERIALS AND METHODS

Fourteen patients affected by generalized vitiligo underwent NB-UVB phototherapy twice weekly for 12 weeks. Before and after phototherapy, a phototesting procedure was administered on vitiligo patches and adjacent healthy skin with a solar simulated radiation (SSR). Visual assessment of the MED took place after 24 h. A spectrophotometer was used to assess the a* value and the melanin index (MI*), as signs of skin erythema and pigmentation. The photoadaptation factor (MED-PF) and the a* photoadaptation factor (a*-PF) were calculated.

RESULTS

After NB-UVB phototherapy, both vitiligo and healthy skin showed an increase in MED and MI* values and a reduction of skin erythema compared to baseline (p < 0.05). MED-PF data showed a photoadaptation in 10 (71.4%) vitiligo lesions and in 12 (85.7%) healthy skin areas. The assessment of the a*-PF showed a negative mean percentage value in all affected and unaffected skin areas.

CONCLUSIONS

A short cycle of NB-UVB phototherapy can induce photoadaptation in vitiligo by increasing the MED and reducing skin erythema after stimulation with SSR. This is most likely due to the physical filter function induced by ultraviolet radiation.

A Rapid and Cost-Effective Device for Testing Minimal Erythema Dose

INTRODUCTION

We describe a novel device for rapid and economical minimal erythema dose testing in patients undergoing ultraviolet (UV) light phototherapy for treatment of skin diseases.

METHODS

A minimal erythema testing device was designed and created using transparent plastic sheeting and printed patterns with increasing ink density, allowing for graded UV transmission of 100%, 80%, 60%, 40%, 20%, and 10% energy through six 10-mm square apertures. The plastic sheet was placed in a UV-impenetrable and Velcro-fitted adjustable sleeve, designed to fit easily onto a patient's arm. A pilot validation study was performed, comparing this device with a commercially available windowed device in which the dose is controlled by varying the UV exposure time through sequential opening of each window. The pilot was conducted on healthy skin of two human subjects with different Fitzpatrick skin types.

RESULTS

In our subjects, tested with one device on each forearm, the minimal erythema dose (MED), judged visually, was identical. However, the test device allowed MED testing in 3 min compared with 15 min for the traditional device. The test device is equally effective for use with ultraviolet-A (UVA), narrowband ultraviolet-B (NB-UVB) and broadband ultraviolet-B (BB-UVB) wavelengths. The test device is economical, with manufacturing cost of less than US $2.

CONCLUSION

We designed an MED testing device that is quick, accurate, cost-effective, and easy to use in the setting of a busy phototherapy practice. This device therefore has many advantages over existing MED testing approaches.

The impact of oral Polypodium leucotomos extract on ultraviolet B response: A human clinical study

BACKGROUND

There is a rationale for adding systemic photoprotective agents to the current photoprotection regimen.

OBJECTIVE

This study was designed to objectively evaluate the molecular and photobiologic effects of oral administration of Polypodium leucotomos extract (PLE).

METHODS

In all, 22 subjects with Fitzpatrick skin phototype I to III were enrolled. On day 1, subjects were irradiated with visible light, ultraviolet (UV) A1, and UVB (using 308-nm excimer laser). Evaluation was done immediately and 24 hours after irradiation. On days 3 and 4, irradiation and evaluation process was repeated after ingestion of PLE.

RESULTS

Clinical assessments and colorimetry data showed a decrease in UVB-induced changes in 17 of 22 subjects post-PLE administration; histology findings demonstrated such a decrease in all 22 subjects.

LIMITATIONS

Only 2 doses of PLE were given. Furthermore, subjects with skin phototypes I to III only were studied.

CONCLUSION

The results suggest that PLE can potentially be used as an adjunctive agent to lessen the negative photobiologic effects of UVB.

Review of narrowband ultraviolet B radiation in vitiligo

Vitiligo is a common, acquired pigmentary disorder of unknown etiology with great impact on patient’s appearance and quality of life. It presents a therapeutic challenge to many dermatologists. Photochemotherapy using psoralen and ultraviolet A (UVA) therapy, topical and oral immunosuppresants, as well as cosmetic camouflage are also commonly employed with varying clinical efficacy. Phototherapy is a popular treatment option, which includes both of the generalized ultraviolet B (UVB) therapies, broadband UVB and narrowband UVB (NB-UVB). It has been used favorably, both alone as well as in combination with other agents like topical calcineurin inhibitors, vitamin-D analogs. Combination therapies are useful and may provide quicker regimentation and treat vitiligo with an additive mechanism of action than UVB phototherapy. Advances in technology may lead to the continuing use of UVB phototherapy as a treatment for vitiligo through the development of sophisticated devices and delivery systems as well as innovative application methods. These will provide increased therapeutic options for all vitiligo patients, particularly those with refractory disease. In this article, I have reviewed the available data pertaining to efficacy and safety issues for NB-UVB as monotherapy, its comparison with psoralen plus UVA and other modes of phototherapy, combination regimens that have been tried and future prospects of NB-UVB in vitiligo.

Chocolate flavanols and skin photoprotection: a parallel, double-blind, randomized clinical trial

BACKGROUND

Solar ultraviolet (UV) radiation has deleterious effects on the skin, including sunburn, photoaging and cancer. Chocolate flavanols are naturally-occurring antioxidant and anti-inflammatory molecules that could play a role in preventing cutaneous UV damage. We investigated the influence of 12-week high-flavanol chocolate (HFC) consumption on skin sensitivity to UV radiation, measured by minimal erythema dose (MED). We also evaluated skin elasticity and hydration.

METHODS

In this 2-group, parallel, double-blind, randomized controlled trial, 74 women aged 20-65 years and Fitzpatrick skin phototypes I or II were recruited from the general community in Quebec City, for randomization to either HFC (n = 33) or low-flavanol chocolate (LFC) (n = 41). A blocked randomisation (4), considering date of entry, skin type and age as factors, generated a sequentially-numbered allocation list. Study participants and research assistants were blinded. Totally, 30 g of chocolate were consumed daily for 12 weeks, followed by a 3-week washout period. MED was assessed at baseline and at 6, 9, 12 and 15 weeks. Main outcome was changes in MED at week 12.

RESULTS

33 participants in the HFC group and 41 in the LFC group were analyzed with 15 weeks of follow-up. Both groups showed similarly-increased MED at 12 weeks (HFC: 0.0252 ± 0.1099 J/cm2 [mean ± standard deviation (SD)]; LFC: 0.0151 ± 0.1118; mean difference (MD): 0.0100 J/cm2; 95% confidence interval (CI): -0.0417 to 0.0618). However, after 3-week washout, the HFC group presented decreased MED (-0.0248 ± 0.1145) whereas no effect was seen in the LFC group (0.0168 ± 0.1698) (MD: -0.0417; 95% CI: -0.1106 to 0.0272). Net temple elasticity increased slightly but significantly by 0.09 ± 0.12 mm in the HFC group at 12 weeks compared to 0.02 ± 0.12 mm in the LFC group (MD: 0.06; 95% CI: 0.01 to 0.12 ). No significant adverse events were reported.

CONCLUSION

Our study failed to demonstrate a statistically-significant protective effect of HFC vs. LFC consumption on skin sensitivity to UV radiation as measured by MED.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01444625.

Comparison of a semiautomated hand-held device to test minimal erythema dose before narrowband ultraviolet B phototherapy with the conventional method using matched doses

BACKGROUND

A semiautomated hand-held device has been introduced in some phototherapy centres to establish the minimal erythema dose (MED) before treatment with narrowband ultraviolet (NBUV) B.

OBJECTIVES

To compare the semiautomated hand-held device with the conventional method of MED testing (a UV-opaque template and a panel of UVB fluorescent tubes), using the same series of incremented doses.

METHODS

Twenty-four patients referred for treatment with NBUVB phototherapy were included. Each patient had MED testing with the conventional method and the semiautomated hand-held device at the same level of the left and right back. The results were read by four investigators each time.

RESULTS

The semiautomated hand-held device was a significant estimator of the MED using the conventional panel method (P < 0.001; r = 0.97). The average ratio of the hand-held MED to the conventional MED was 67%. The mean difference between the methods was 165 mJ/cm(2) . The interobserver test showed very high agreement for both methods of MED testing (Cronbach α coefficient 0.97 for the hand-held MED tester vs. 0.93 for the conventional method).

CONCLUSIONS

The semiautomated hand-held device MED results were lower than that of the conventional panel method and may prolong the treatment course by 2-3 treatments. The hand-held tester is a fast and reproducible method, and may allow more phototherapy units, limited by staff and time, to do MED testing.

Minimal Erythema Dose (MED) testing

Ultraviolet radiation (UV) therapy is sometimes used as a treatment for various common skin conditions, including psoriasis, acne, and eczema. The dosage of UV light is prescribed according to an individual's skin sensitivity. Thus, to establish the proper dosage of UV light to administer to a patient, the patient is sometimes screened to determine a minimal erythema dose (MED), which is the amount of UV radiation that will produce minimal erythema (sunburn or redness caused by engorgement of capillaries) of an individual's skin within a few hours following exposure. This article describes how to conduct minimal erythema dose (MED) testing. There is currently no easy way to determine an appropriate UV dose for clinical or research purposes without conducting formal MED testing, requiring observation hours after testing, or informal trial and error testing with the risks of under- or over-dosing. However, some alternative methods are discussed.

Sun protection advice mediated by the general practitioner: an effective way to achieve long-term change of behaviour and attitudes related to sun exposure?

OBJECTIVE

To investigate, in primary health care, differentiated levels of prevention directed at skin cancer, and how the propensity of the patients to change sun habits/sun protection behaviour and attitudes towards sunbathing were affected, three years after intervention. Additionally, the impact of the performance of a phototest as a complementary tool for prevention was evaluated.

DESIGN

Randomized controlled study. Setting and subjects. During three weeks in February, all patients ≥ 18 years of age registering at a primary health care centre in southern Sweden were asked to fill in a questionnaire mapping sun exposure habits, attitudes towards sunbathing, and readiness to increase sun protection according to the Transtheoretical Model of Behaviour Change (TTM) (n = 316). They were randomized into three intervention groups, for which sun protection advice was given, in Group 1 by means of a letter, and in Groups 2 and 3 orally during a personal GP consultation. Group 3 also underwent a phototest to demonstrate individual skin UV sensitivity.

MAIN OUTCOME MEASURES

Change of sun habits/sun protection behaviour and attitudes, measured by five-point Likert scale scores and readiness to increase sun protection according to the TTM, three years after intervention, by a repeated questionnaire.

RESULTS

In the letter group, almost no improvement in sun protection occurred. In the two doctor's consultation groups, significantly increased sun protection was demonstrated for several items, but the difference compared with the letter group was significant only for sunscreen use. The performance of a phototest did not appear to reinforce the impact of intervention.

CONCLUSION

Sun protection advice, mediated personally by the GP during a doctor's consultation, can lead to improvement in sun protection over a prolonged time period.