R.S. Dawe

Incidence of skin cancers in 3867 patients treated with narrow-band ultraviolet B phototherapy.

Background Narrow‐band ultraviolet B (NB‐UVB) phototherapy is a widely used treatment. Psoralen‐UVA photochemotherapy (PUVA) increases skin cancer risk and some animal studies have raised the possibility of an increased risk with NB‐UVB. The risk of skin cancer in humans following treatment with NB‐UVB is unknown.

An update and guidance on narrowband ultraviolet B phototherapy: a British Photodermatology Group Workshop Report.

Summary These guidelines for use of narrowband (TL‐01) ultraviolet B have been prepared for dermatologists by the British Photodermatology Group on behalf of the British Association of Dermatologists. They present evidence‐based guidance for treatment of patients with a variety of dermatoses and photodermatoses, with identification of the strength of evidence available at the time of preparation of the guidelines, and a brief overview of background photobiology.

Topical 5-aminolaevulinic acid photodynamic therapy for cutaneous lesions: outcome and comparison of light sources

Background: Topical 5‐aminolaevulinic acid (ALA) photodynamic therapy (PDT) is increasingly used for superficial non‐melanoma skin cancers and their precursors.

Cutaneous expression of cytochrome P450 CYP2S1: individuality in regulation by therapeutic agents for psoriasis and other skin diseases

BACKGROUND Treatment of common skin diseases such as psoriasis is complicated by differences between individuals in response to topical drug treatment and photochemotherapy. Individuality in hepatic expression of drug-metabolising enzymes is an important determinant of systemic drug handling; we investigated whether similar variation in cutaneous gene expression contributes to individuality in response to topical therapies. METHODS We used quantitative real-time RT-PCR to demonstrate the expression in skin of a recently identified cytochrome P450, CYP2S1, in healthy volunteers (n=27) and patients with psoriasis (n=29). We also investigated regulation of CYP2S1 by ultraviolet radiation, psoralen-ultraviolet A (PUVA), and topical drugs used to treat psoriasis. FINDINGS We found that CYP2S1 is expressed in skin and showed pronounced individuality in constitutive expression of the enzyme and its induction after ultraviolet irradiation or topical drug treatment. Cutaneous expression of CYP2S1 was induced by ultraviolet radiation, PUVA, coal tar, and all-trans retinoic acid; expression was significantly higher in lesional psoriatic skin than in adjacent non-lesional skin (geometric mean 3.38 [95% CI 2.64-4.34] times higher; p<0.0001), which implies that topical drugs are differentially metabolised in psoriatic plaque and non-lesional skin. We showed that all-trans retinoic acid is metabolised by CYP2S1, which has higher cutaneous expression than CYP26, previously described as the specific cutaneous P450 retinoic-acid-metabolising enzyme. INTERPRETATION These findings increase our understanding of the interaction between therapeutic agents and the skin and suggest a functional role for CYP2S1 in the metabolism of topical drugs and in mediating the response to photochemotherapy in psoriasis.

The photocarcinogenic risk of narrowband UVB (TL-01) phototherapy: early follow-up data.

Background  Limited information is available on the carcinogenic risk associated with narrowband TL‐01 UVB phototherapy in humans.

Ultraviolet A1 phototherapy

Summary  Long‐wavelength ultraviolet A (340–400 nm; UVA1) therapy is currently available in only a few dermatology departments. Equipment capable of delivering this waveband has been available since 1981, but it is only over the past decade that increasing numbers of studies assessing the potential of this as a therapy have been published. High‐dose UVA1, which requires expensive and space‐occupying apparatus, is effective as a monotherapy for acute flares of atopic dermatitis, but it has not yet been formally assessed as an adjunct, rather than as an alternative to conventional therapies including potent and very potent topical corticosteroids. Low‐dose (which can be administered using a standard phototherapy cubicle fitted with appropriate lamps) and medium‐dose UVA1 may be less effective for this indication. Another condition for which UVA1 is effective, and is particularly promising because we have no reliably effective treatment already, is localized scleroderma. It also appears to be effective in systemic lupus erythematosus (although it is not yet clear when it is indicated, and its safety needs to be assessed in more patients) and in polymorphic light eruption (although there have been no studies suggesting that UVA1 will have any advantages over standard prophylactic phototherapies). Open studies and case series suggest that UVA1 may prove beneficial for various other diseases, including cutaneous T‐cell lymphoma, lichen sclerosus, keloids, systemic sclerosis and hand dermatitis. In the centres where it is available, UVA1 has already proved a useful addition to the range of phototherapies previously available. However, much more research is needed to confirm its efficacy for many of its potential indications, and to determine when and how it should be used.

A randomized, double‐blind, placebo‐controlled study of the efficacy of tetracaine gel (Ametop®) for pain relief during topical photodynamic therapy

Background  Many patients find topical 5‐aminolaevulinic acid (ALA) photodynamic therapy (PDT) painful. Local anaesthetics are not routinely used and their effect on PDT pain has not been examined.

A pilot study of treatment of lentigo maligna with 5% imiquimod cream.

Background  Lentigo maligna (LM) is an in situ form of malignant melanoma, and surgical excision is often unsatisfactory. Imiquimod cream is an immune response modifier and induces a predominantly T‐helper 1 type response.

A randomized, observer‐blinded trial of twice vs. three times weekly narrowband ultraviolet B phototherapy for chronic plaque psoriasis

Summary Background The optimum treatment frequency for narrowband (TL‐01) ultraviolet B (NB‐UVB) in psoriasis is not yet known. We have previously found three times weekly to be preferable to five times weekly treatment in our population.

A randomized controlled trial of narrowband ultraviolet B vs bath-psoralen plus ultraviolet A photochemotherapy for psoriasis.

Summary Background  In 1991, consensus guidelines recommended psoralen plus ultraviolet A photochemotherapy (PUVA) for those requiring second‐line therapy for psoriasis. Narrowband (TL‐01) UVB has since become more widely available, replacing the less effective broadband sources.