M.J.P. Gerritsen

Daylight photodynamic therapy for actinic keratosis: an international consensus: International Society for Photodynamic Therapy in Dermatology.

Photodynamic therapy (PDT) is an attractive therapy for non‐melanoma skin cancers including actinic keratoses (AKs) because it allows treatment of large areas; it has a high response rate and results in an excellent cosmesis. However, conventional PDT for AKs is associated with inconveniently long clinic visits and discomfort during therapy. In this article, we critically review daylight‐mediated PDT, which is a simpler and more tolerable treatment procedure for PDT. We review the effective light dose, efficacy and safety, the need for prior application of sunscreen, and potential clinical scope of daylight‐PDT. Three randomized controlled studies have shown that daylight‐mediated PDT is an effective treatment of thin AKs. Daylight‐mediated PDT is nearly pain‐free and more convenient for both the clinics and patients. Daylight‐mediated PDT is especially suited for patients with large field‐cancerized areas, which can easily be exposed to daylight. Further investigations are necessary to determine at which time of the year and in which weather conditions daylight‐mediated PDT will be possible in different geographical locations.

Pretreatment to Enhance Protoporphyrin IX Accumulation in Photodynamic Therapy

The response rates of photodynamic therapy (PDT) vary widely. Limited uptake of topically applied 5-aminolaevulinic acid (ALA), or its methyl ester (MAL), and suboptimal production of protoporphyrin IX (PpIX) may account for these differences. Recently, we demonstrated that hyperkeratosis is an important negative factor in ALA uptake. This review has its focus on pretreatment of the skin in order to improve the clinical outcome of ALA/MAL PDT. Pretreatment of hyperkeratosis can be achieved with keratolytics, curettage/debulking, tape stripping, microdermabrasion or laser ablation. Penetration enhancers may alter the composition or organization of the intercellular lipids of the stratum corneum. Several studies have been performed on the use of dimethyl sulfoxide, azone, glycolic acid, oleic acid and iontophoresis to increase the penetration of ALA. As PpIX production is also dominated by temperature-dependent processes, elevating skin temperature during ALA application may also improve treatment results. Another approach is the use of additives that interact with the heme biosynthetic pathway, e.g. by removing ferrous iron with iron-chelating substances such as: ethylenediaminetetraacetic acid; 3-hydroxypyridin-4-ones; 1,2-diethyl-3-hydroxypyridin-4-one-hydrochloride; and desferrioxamine. In conclusion, simple pretreatments or additions to the regular practice of PDT, aimed to optimize intralesional PpIX content, improve the clinical outcome.

The Impact of Chronic Skin Disease on Daily Life (ISDL): a generic and dermatology-specific health instrument

Background  In dermatological research and clinical practice, there is a need for comprehensive self‐report instruments that assess a broad spectrum of health implications of chronic skin diseases, including generic and skin‐specific aspects of disease‐related quality of life. The advantages of dermatology‐specific, multidimensional instruments over generic instruments or single‐dimensional quality‐of‐life measures are in the detailed and specific information they provide about health areas that are affected by the skin condition and that may change through therapeutic intervention.

Photodynamic therapy for skin field cancerization: an international consensus. International Society for Photodynamic Therapy in Dermatology

Field cancerization is a term that describes the presence of genetic abnormalities in a tissue chronically exposed to a carcinogen. These abnormalities are responsible for the presence of multilocular clinical and sub‐clinical cancerous lesions that explains the increased risks of multiple cancers in this area. With respect to the skin, this term is used to define the presence of multiple non‐melanoma skin cancer, its precursors, actinic keratoses and dysplastic keratinocytes in sun exposed areas. The multiplicity of the lesions and the extent of the area influence the treatment decision. Providing at least equivalent efficacy and tolerability, field directed therapies are therefore often more worthwhile than lesion targeted approaches. Photodynamic therapy (PDT) with its selective sensitization and destruction of diseased tissue is one ideal form of therapy for this indication. In the following paper the use of PDT for the treatment of field cancerized skin is reviewed and recommendations are given for its use.

A placebo-controlled randomized study on the clinical effectiveness, immunohistochemical changes and protoporphyrin IX accumulation in fractionated 5-aminolaevulinic acid-photodynamic therapy in patients with psoriasis

Background  Topical 5‐aminolaevulinic acid (ALA)‐photodynamic therapy (PDT) for the treatment of psoriasis has been evaluated in a few studies. In these studies different treatment parameters were used, there was a variable clinical response, and a nonhomogeneous fluorescence was seen after irradiation with Woods light.

Repeated tape stripping of normal skin: a histological assessment and comparison with events seen in psoriasis

The aim of the present study was to investigate the response of normal human skin to repeated courses of Sellotape stripping. The skin of healthy volunteers was stripped five times at 24-h intervals. Skin biopsies were taken before stripping (day 0) and on days 2, 4, 7 and 10. The responses were studied using H & E staining and an immunohistochemical analysis of several aspects of epidermal proliferation and keratinization. Although increased proliferation (nuclear binding to Ki-67 binding), acanthosis and parakeratosis were observed, the overall histological picture did not resemble psoriatic histology completely: no micropustules of Kogoj and no thinning of the suprapapillary plate were observed. Involucrin staining followed the recruitment of cycling epidermal cells showing a statistically significant elevation of positive cell layers from day 2 onwards. Filaggrin expression showed an increase from day 2 onwards, which was statistically significant on day 7 and day 10. Using the anti-keratin antibodies KS8.12 (K13 and K16) and RKSE60 (K10) we observed a fast induction of K13/K16 expression, while the staining of keratin 10 showed the same overall intensity at different time intervals. In conclusion, the response to repeated courses of tape stripping provides an adequate model for studies on epidermal proliferation, hypergranulosis and hyperkeratosis. This approach causes a more prolonged induction of these phenomena than a single course of stripping. In contrast to the situation following a single course of stripping, repeated tape stripping induced the expression of filaggrin. Therefore the repeated tape stripping model is less compatible with psoriasis than a single course of stripping.

High discordance between punch biopsy and excision in establishing basal cell carcinoma subtype: analysis of 500 cases

Background  Basal cell carcinoma (BCC) is the most frequently occurring cancer in humans. Worldwide incidences rise about 10% each year, increasing the burden on dermatologists, general practitioners and pathologists as well as increasing costs for the health care system. Increasingly non‐surgical treatment options are used in the treatment of BCC, without histological confirmation of BCC subtype, potentially resulting in under‐treatment.

Recruitment of cycling epidermal cells and expression of filaggrin, involucrin and tenascin in the margin of the active psoriatic plaque, in the uninvolved skin of psoriatic patients and in the normal healthy skin

The peripheral changes in the uninvolved skin adjacent to the extending psoriatic lesions may represent early events. The sequence of these events remains controversial. In the present study we evaluated epidermal and dermal aspects of the margin of the progressive psoriatic plaque, the distant uninvolved skin and normal healthy skin, using immunohistochemistry with markers for keratinization, proliferation and connective tissue: filaggrin, involucrin, Ki-67 and tenascin. The results showed that: (i) processes in distant uninvolved skin were comparable with the observations in normal skin; (ii) in the margin zone of the spreading psoriatic lesion, following the increased appearance of tenascin, the transition into parakeratosis, abnormal expression of filaggrin, involucrin and recruitment of cycling epidermal cells, happened simultaneously. The simultaneous normalization of these epidermal processes might be a consequence of a signal which is simultaneously transduced to the basal and suprabasal cell layers of the epidermis. Based on the present results and earlier findings, we would like to propose a triple stage model for the development of the psoriatic lesion: Stage 1, involvement of the stroma; stage II, inflammatory infiltrate formation and penetration into the upper layers of the epidermis, with suprabasal expression of keratin 16; stage III, recruitment of cycling epidermal cells and abnormal terminal differentiation. Further studies are required on the regulation of tenascin expression, focusing on factors derived from the stroma affecting both recruitment of cycling epidermal cells, involucrin and filaggrin expression. An intermediate step in the dermo-epithelial interrelation is the inflammatory infiltrate, penetrating into the most superficial zone of the epidermis, and the suprabasal expression of keratin 16.

Narrowband ultraviolet B therapy in psoriasis: randomized double-blind comparison of high-dose and low-dose irradiation regimens

Background  Ultraviolet (UV) B phototherapy is an established treatment option for psoriasis. The optimum dosage regimen still has to be determined. Within‐subject comparisons do not take into account the systemic effects of UVB phototherapy. The area of the body treated with low‐dose UVB may benefit from the systemic effects of the site treated with a higher UVB dose.

Photodynamic therapy for actinic keratosis in organ transplant patients

Background  The incidence of actinic keratoses (AK) and non‐melanoma skin cancer (NMSC) in organ transplant recipients (OTRs) is significantly higher than in immunocompetent patients. Rates of progression and recurrence following treatment are higher too, in part due to the effects of the immunosuppressant drugs. Conventional therapies for AK, using curettage, cryotherapy, surgical excision, topical therapies and photodynamic therapy (PDT), are often less effective, and may be inappropriate, for treating the greater numbers and extent of lesions in OTRs. Moreover, there are no specific protocols for treating this patient population that take into account the need for more frequent treatment and the increased pain associated with treating larger areas.