Photodiagnostic services in the UK and Republic of Ireland: a British Photodermatology Group Workshop Report.

BACKGROUND: Photodiagnostic investigations are essential for the accurate diagnosis of abnormal cutaneous photosensitivity and provide important information for the management of patients with photodermatoses (cutaneous photosensitivity disorders). Although photodiagnosis has been undertaken since the early 1970s, specialist services in the United Kingdom (UK) and Republic of Ireland are limited and there is no formal guidance on diagnostic approach. Indeed, there is a limited literature in this area of methodology and diagnostic practice. OBJECTIVES: The primary objective was to undertake a British Photodermatology Group Workshop to review the role and activities of specialist centres in the UK and Republic of Ireland in order to ascertain whether there were consensus practices. Secondary objectives were to identify key priorities for service, training and research. METHODS: An initial detailed survey review of current activities was undertaken prior to the Workshop and data from this survey were used to inform discussion at the Workshop, which was attended by key photodermatology experts from the UK and Republic of Ireland. RESULTS/CONCLUSIONS: We have undertaken a detailed review of current Photodiagnostic Services in the UK and Republic of Ireland and report on our findings from the 12 centres and we have identified key areas of consensus practice. This is an important step in the process of standardising and optimising procedures and protocols and defining minimum clinical standards for photodiagnostic investigations, which are of such diagnostic importance in Dermatology.

Fluorescence and thermal imaging of non-melanoma skin cancers before and during photodynamic therapy.

BACKGROUND: Photodynamic therapy (PDT) has been shown to be less effective on the extremities. Protoporphyrin-IX (PpIX) fluorescence and skin surface temperature are variables that have been implicated in the differences in efficacy with body site, but objective studies have not been undertaken. OBJECTIVES: To further investigate observations from our previous study that temperature and fluorescence during pro-drug incubation are correlated, through a prospective objective investigation of the relationships between fluorescence and skin surface temperature before and during PDT and relationships with body site and efficacy. METHODS: Eighteen patients with Bowen's disease or basal cell carcinoma, who had been referred for PDT, were recruited to this study. PpIX fluorescence and thermal measurements were recorded at intervals during the pro-drug incubation and irradiation phases of PDT. Pain immediately after irradiation, and outcome at 3- and 12-months were recorded. RESULTS: Temperature and PpIX fluorescence were higher on the trunk than lower leg immediately before treatment (median temperature 32.7 °C vs. 27.8 °C, p < 0.05 and median fluorescence 16.5 vs. 6.7, p < 0.05). Higher pain levels were reported during PDT on the extremities (median 5.7 vs. 2.2, p < 0.05). Clearance rates at 12-months were 80 %. CONCLUSIONS: The study supports a correlation between temperature and PpIX fluorescence during PDT, providing robust objective data to support our previous hypothesis and observations. The higher pain levels, lower PpIX fluorescence on the lower leg, and the high efficacy rates at all body sites irrespective of temperature and fluorescence indicates that relationships between PDT treatment conditions and parameters is likely to be multifactorial.

Use of illuminance as a guide to effective light delivery during daylight photodynamic therapy in the U.K.

BACKGROUND: Daylight PDT (dPDT) is an effective and nearly painless treatment for field-change actinic keratosis. Measuring the protoporphyrin-IX (PpIX)-weighted exposure dose can give an indication of when conditions are most viable for effective dPDT. It would be advantageous for practitioners if more detailed information of exposure dose and appropriate treatment conditions were available. Where sophisticated measurement equipment is unavailable, simpler and more cost-effective methods of dose measurement are desirable. OBJECTIVES: To devise a model whereby illuminance data can be converted into PpIX-weighted exposure dose, and to use this model to estimate appropriate times for dPDT across the U.K. and Ireland. METHODS: Spectral irradiance data were analysed to obtain a conversion model for illuminance to PpIX-weighted dose. This model was applied to historic illuminance data from nine sites to obtain PpIX-weighted dose across the U.K. and Ireland. Temperature data and an analysis of conservatory-based dPDT were also considered. RESULTS: Distribution of the expected PpIX-weighted dose across the nine locations is presented. Temperature data showed that it could be too cold for dPDT, even when there is sufficient light exposure. Conservatory-based dPDT could extend the times in the year for possible treatment. CONCLUSIONS: This proposed conversion model provides a means of using an illuminance reading to calculate the PpIX-weighted exposure dose. Dosimetry of dPDT may be carried out simply and at low cost using the presented method; however, the results presented may be used as a guide for those considering dPDT, without the need to conduct measurements themselves.

Nine out of 10 sunbeds in England emit ultraviolet radiation levels that exceed current safety limits.

BACKGROUND: Exposure to ultraviolet (UV) radiation from sunlight is recognized as the principal cause of skin cancer. Moreover, sunbeds have been classified as carcinogenic by the International Agency for Research on Cancer. Despite this, there is a shortage of objective data on UV exposure levels in sunbeds in England. OBJECTIVES: We set out to measure UV emission levels in sunbeds at sites around England, and to compare these levels with both current standards and natural sunlight. METHODS: Between October 2010 and February 2011, UV spectra were measured on site from a total of 402 artificial tanning units in England. Measurement instrumentation was calibrated, traceable to the National Physical Laboratory. Compliance with the relevant British and European standard was determined, and a skin-cancer weighting factor was used to compare the carcinogenic potential of sunbeds with that of sunlight. RESULTS: For compliance with the European standard, erythemal-effective irradiance should not exceed 0·3 W m(-2). The values that we measured ranged between 0·10 and 1·32 W m(-2) with a mean of 0·56 ± 0·21 W m(-2) . Only 10% of sunbeds surveyed were within the recommended limit. Application of the skin-cancer weighting factor produced values that varied from 0·17 to 2·52 W m(-2) with a mean of 0·99 ± 0·41 W m(-2). The comparable value for Mediterranean noon day sun was 0·43 W m . CONCLUSIONS: Nine out of 10 sunbeds surveyed throughout England emitted levels of UV radiation that exceed the maximum levels contained within the European standard. Moreover, the skin cancer risk for comparable times of exposure was up to six times higher than that for Mediterranean sunlight. This situation is unacceptable and stricter control measures must be put in place.

A preliminary investigation into the effect of exposure of photosensitive individuals to light from compact fluorescent lamps.

BACKGROUND: Compact fluorescent lamps (CFLs) are due to replace common incandescent lamps over the next few years. There has been no investigation of the possible effect of this on patients with photosensitive disorders. OBJECTIVES: To determine the effect of exposure of photosensitive individuals to light from CFLs. METHODS: The spectral emission from a sample of CFLs was measured using a calibrated spectroradiometer. The erythemal response was determined in one normal individual and four photosensitive individuals by direct exposure of the skin to light from a CFL. The susceptibility of a wider group of photosensitive individuals was predicted based on the light dose known to elicit a reaction during phototesting at discrete ultraviolet (UV) wavelengths. RESULTS: CFLs emit UV radiation at wavelengths down to 254 nm. Prolonged exposure of a normal individual's skin produced erythema. However, an exposure of only 2.5 min at 5 cm elicited marked erythema in one of the abnormally photosensitive patients. CONCLUSIONS: CFLs could be a source of harmful UV radiation to photosensitive individuals. Patients with chronic actinic dermatitis are thought to be at greatest risk. The use of a protective envelope is recommended.

A clinical evaluation of a screening (Microstix) for urinary tract infections.

The effectiveness of a screening device for urinary tract infection (Microstix**) was compared to routine laboratory cultures, sensitivities, and colony counts. The Microstix were highly effective in determining the presence or absence of urinary tract infections. In addition, they could be subcultured to provide meaningful bacterial sensitivities. Microstix are economical, easy to use, and accurate. Their use in the diagnosis and follow-up of urinary tract infections is therefore recommended.