How to write a Critically Appraised Topic: evidence to underpin routine clinical practice.

Critically appraised topics (CATs) are essential tools for busy clinicians who wish to ensure that their daily clinical practice is underpinned by evidence-based medicine. CATs are short summaries of the most up-to-date, high-quality available evidence that is found using thorough structured methods. They can be used to answer specific, patient-orientated questions that arise recurrently in real-life practice. This article provides readers with a detailed guide to performing their own CATs. It is split into four main sections reflecting the four main steps involved in performing a CAT: formulation of a focused question, a search for the most relevant and highest-quality evidence, critical appraisal of the evidence and application of the results back to the patient scenario. As well as helping to improve patient care on an individual basis by answering specific clinical questions that arise, CATs can help spread and share knowledge with colleagues on an international level through publication in the evidence-based dermatology section of the British Journal of Dermatology.

Drug-induced photosensitivity: new insights into pathomechanisms and clinical variation through basic and applied science.

Drug-induced photosensitivity occurs when a drug is capable of absorbing radiation from the sun (usually ultraviolet A) leading to chemical reactions that cause cellular damage (phototoxicity) or, more rarely, form photoallergens (photoallergy). The manifestation varies considerably in presentation and severity from mild pain to severe blistering. Despite screening strategies and guidelines in place to predict photoreactive drugs during development there are still new drugs coming onto the market that cause photosensitivity. Thus, there is a continuing need for dermatologists to be aware of the different forms of presentation and the culprit drugs. Management usually involves photoprotection and cessation of drug treatment. However, there are always cases where the culprit drug is indispensable. The reason why some patients are susceptible while others remain asymptomatic is not known. A potential mechanism for the phototoxic reactions is the generation of reactive oxygen species (ROS), and there are a number of reasons why some patients might be less able to cope with enhanced levels of ROS.

Erythema action spectrum of topical 8-methoxypsoralen-sensitized skin re-evaluated: implications for routine clinical practice.

BACKGROUND: Published methodology used to determine psoralen plus ultraviolet A (PUVA) erythemal action spectrum does not reflect current clinical practice for psoralen sensitization. We re-evaluated the PUVA action spectrum using aqueous 8-methoxypsoralen (8-MOP) 2·6 mg L(-1) as used routinely in current clinical practice. OBJECTIVES: To determine the UVA erythema action spectrum of topical 8-MOP-sensitized normal skin. METHODS: Twenty healthy volunteers with skin phototypes I-V were recruited. Forearms were psoralen-sensitized at 37 °C for 10 min. Six UVA irradiations at 10-nm intervals between 325 and 375 nm were randomly allocated to forearm sites and were applied using a 10-nm bandwidth irradiation monochromator. The visual minimal phototoxic dose (MPD) was recorded on each site at 96 h. RESULTS: Volunteer Boston phototypes were: I, n = 2; II, n = 6; III, n = 6; IV, n = 5 and V, n = 1. The mean MPD (J cm(-2) ) for all subjects at each wavelength was as follows: 325 nm, 0·64 (SD 0·37); 335 nm, 0·80 (SD 0·58); 345 nm, 0·96 (SD 0·55); 355 nm, 1·50 (SD 0·85); 365 nm, 2·19 (SD 0·90); and 375 nm, 2·89 (SD 1·06). Therefore, the relative sensitization at each wavelength (erythemal action spectrum) was: 1, 0·83, 0·67, 0·43, 0·29 and 0·22. There were significant differences between the PUVA erythemal effectiveness at different wavelengths but none between skin types. CONCLUSIONS: This study has established the erythemal action spectrum for bath/soak PUVA therapy as is currently performed. In all volunteers, the peak sensitivity was at 325 nm. All volunteers showed a similar trend across the wavelengths studied irrespective of skin type. The determination of the action spectrum for PUVA-induced erythema is important as it permits reliable estimates of erythemal efficacy of any UVA source where the emission spectrum of the lamp is known or can be measured.

Home phototherapy for psoriasis: a review and update.

A 2006 survey of dermatologists showed that home phototherapy should be used with caution, and that general, nonevidence-based opinions were widespread about this form of therapy. This led to a randomized controlled trial to assess the safety and efficacy of home phototherapy vs. outpatient phototherapy by the same authors in 2009, which concluded that a lower burden of treatment and increased patient satisfaction were associated with home phototherapy. In the UK National Health Service, with a single exception, phototherapy is currently carried out exclusively in hospital. This contrasts with the Netherlands, where home phototherapy is now widely available. NHS dermatology services in the UK have yet to adopt home phototherapy as a treatment option, despite the strong evidence base and robust service models established elsewhere. In this review, we discuss evidence-based papers on home phototherapy, its advantages and disadvantages, economic effectiveness, and a suggested model for service sustainability.