A.C. Chu

Phototherapy with blue (415 nm) and red (660 nm) light in the treatment of acne vulgaris

In this study we have evaluated the use of blue light (peak at 415u2003nm) and a mixed blue and red light (peaks at 415 and 660u2003nm) in the treatment of acne vulgaris. One hundred and seven patients with mild to moderate acne vulgaris were randomized into four treatment groups: blue light, mixed blue and red light, cool white light and 5% benzoyl peroxide cream. Subjects in the phototherapy groups used portable light sources and irradiation was carried out daily for 15u2003min. Comparative assessment between the three light sources was made in an observer‐blinded fashion, but this could not be achieved for the use of benzoyl peroxide. Assessments were performed every 4u2003weeks. After 12u2003weeks of active treatment a mean improvement of 76% (95% confidence interval 66–87) in inflammatory lesions was achieved by the combined blue–red light phototherapy; this was significantly superior to that achieved by blue light (at weeks 4 and 8 but not week 12), benzoyl peroxide (at weeks 8 and 12) or white light (at each assessment). The final mean improvement in comedones by using blue–red light was 58% (95% confidence interval 45–71), again better than that achieved by the other active treatments used, although the differences did not reach significant levels. We have found that phototherapy with mixed blue–red light, probably by combining antibacterial and anti‐inflammatory action, is an effective means of treating acne vulgaris of mild to moderate severity, with no significant short‐term adverse effects.

Topical calcipotriol as monotherapy and in combination with psoralen plus ultraviolet A in the treatment of vitiligo.

Background u2003Recent advances in the pathophysiology of vitiligo have demonstrated defective calcium homeostasis in depigmented skin. 1,25‐Dihydroxyvitamin D3 may be involved in the regulation of melanin synthesis, and receptors for 1,25‐dihydroxyvitamin D3 have been demonstrated on melanocytes.

Investigation of the mechanism of action of nonablative pulsed-dye laser therapy in photorejuvenation and inflammatory acne vulgaris

Backgroundu2002 Nonablative lasers are widely used for treatment of wrinkles, atrophic scars and acne. These lasers stimulate dermal remodelling and collagen production, but the early molecular stimulus for this is unknown. The mechanism of nonablative lasers in inflammatory acne is variously suggested to be damage either to sebaceous glands or to Propionibacterium acnes. Their effects on cytokine production are unknown.

The confusing state of the histiocytoses.

The histiocytoses are reactive or malignant conditions in which various tissues, including the skin, are infiltrated by cells of the monocyte macrophage lineage. They are a heterogeneous group of disorders that are made very confusing by their rarity and by the large number of terms that have been used to describe them. The Writing Group of the Histiocyte Society have reclassified the histiocytoses into three classes: Class 1: Langerhans cell histiocytosis. Class 2: Non-Langerhans cell histiocytoses Class 3: Malignant histiocytoses. This classification has been generally adopted and has been very useful, particularly in Langerhans cell histiocytosis. It still leaves, however, an enormous group of Class 2 histiocytoses that are very diverse and still very confusing. Many of these conditions have been reported in the literature only on a few occasions and full investigation of the patients, particularly with respect to histology and immune histochemistry, have not been performed. Histiocytes in themselves are a diverse group of cells, having the CD341 bone marrow precursor as their progenitor cell but then entering a number of rather confusing ontological pathways to finally become morphologically recognizable cells in the skin and other tissues. One type of histiocyte was first identified in 1986 by Hedington, who termed the cell `a dermal dendrocyte. Unfortunately, little is known about the kinetics and turnover of the dermal dendrocyte and, although we assume that the bone marrow CD341 cell is the precursor, this has not been scientifically demonstrated. Dermal dendrocytes are MHC Class II antigenpositive, suggesting a role in antigen presentation, but functional studies on their immune function have not been conducted to date. An important surface marker for the dermal dendrocyte is the blood clotting transglutaminase Factor XIIIa. The presence of this factor on the dermal dendrocytes has led to speculation that this cell could have a function in controlling blood loss following damage to the superficial plexus of blood vessels in the skin. In normal human skin dermal dendrocytes are found in the upper papillary dermis perivascularly and around adnexal structures.

Abnormal immunoreactivity of the E-cadherin/catenin (α-, β-, and γ-) complex in premalignant and malignant non-melanocytic skin tumours

E‐cadherin/catenin (α‐, β‐, and γ‐) complex plays a critical role in the control of epithelial differentiation. The aim of this study was to examine the immunoreactivity of E‐cadherin and α‐, β‐, and γ‐catenins in premalignant and malignant non‐melanocytic skin tumours (NMST) and to correlate their expression with the grade of tumour differentiation, as assessed by the established histopathological criteria and by the Ki‐67 index. Benign NMSTs were also studied. To investigate any possible influence of immunosuppression in the expression of E‐cadherin and catenins, the study compared tumours obtained from renal transplant recipients (RTRs) and immunocompetent patients. Immunoperoxidase staining of E‐cadherin and α‐, β‐, and γ‐catenins was performed in 42 squamous cell carcinomas (SCCs) (26 from RTRs and 16 from non‐RTRs), 30 lesions of Bowens disease (11 from RTRs and 19 from non‐RTRs), 11 atypical squamoproliferative lesions from RTRs, 19 actinic keratoses (9 from RTRs and 10 from non‐RTRs), and 20 viral warts from RTRs. The findings of this study were as follows. Firstly, the probability of abnormal expression of E‐cadherin and α‐, β‐, and γ‐catenins increased from benign to premalignant and malignant NMSTs (p<0.001 for all). Secondly, there was agreement in abnormal expression between most of the molecules measured in malignant and premalignant NMSTs (p<0.05). Thirdly, in SCC, abnormal expression of E‐cadherin and catenins was more frequent in lesions with a high (>40%) Ki‐67 index than in those with a low Ki‐67 index (<40%) (p=0.003). However, only the abnormal expression of γ‐catenin increased with the grade of SCC differentiation (p=0.008). Fourthly, abnormal expression of γ‐catenin predicted a high proliferation index (Ki‐67 index 40%) in NMSTs (p<0.01, OR=6.19). Finally, there was no difference in the abnormal expression of E‐cadherin and catenins between NMSTs from immunosuppressed and immunocompetent patients. Thus, abnormal expression of the E‐cadherin/catenin complex was quite common in SCC and Bowens disease and also in a proportion of intraepithelial dysplastic lesions, such as atypical squamoproliferative lesions and actinic keratosis, suggesting that these changes may be early indicators of the neoplastic process. Abnormal expression of γ‐catenin was the sole predictor of high proliferation in NMST and was also correlated with the tumour grade, suggesting a possible important role for γ‐catenin in tumourigenesis. Copyright

p53 induction in normal human skin in vitro following exposure to solar simulated UV and UV-B irradiation.

Exposure of normal human breast skin ex vivo to physiological levels of UV-B and solar simulated UV results in a UV dose- and time-dependent increase in epidermal p53, as determined by PAGE analysis. Peak p53 levels are detected 12 to 24 h post irradiation with UV-B (470-1410 mJ cm-2) and solar simulated UV (5-12 minimal erythema dose (MED) equivalents). Irradiation with an FS20 UV-B lamp, contaminated with UV-A and UV-C (74-1111 mJ cm-2), also induces peak levels after 12 h incubation at 37 degrees C but these levels persist to 36 h post UV irradiation. In all cases p53 levels start to return to normal by 48 h culture. A significant positive correlation is demonstrated between UV-B dose (47-1645 mJ cm-2) and p53 level (p < 0.01, R > 0.977) in explants cultured for 24 h at 37 degrees C post irradiation. The FS20 induces a UV-B dose-dependent increase in p53 to a maximum from 370 to 1111 mJ cm-2. Similarly, solar simulated UV induces a plateau of peak p53 induction between 5 and 15 MED equivalents. Immunohistochemical analysis using microwave retrieval on 5 microns sections shows the same pattern of p53 staining with UV-B and solar UV insult, but proves unreliable as a method of quantification. These results suggest that the skin explant model may be a useful tool in the evaluation of UV-induced epidermal cell damage, providing a valuable alternative to in vivo studies.

Treatment of xanthoma disseminatum with cyclophosphamide

Xanthoma disseminatum is a rare non‐Langerhans cell (class II) histiocytosis, which is often resistant to treatment. We describe an illustrative case with extensive mucocutaneous, ocular, laryngeal, pituitary and central nervous system involvement, which responded to treatment with cyclophosphamide. The presentation, course and treatment of the condition are reviewed. Many of the non‐Langerhans cell histiocytoses represent a spectrum of diseases of dermal dendrocytes ranging from self‐limiting and benign conditions to multisystem progressive diseases that respond poorly to treatment and severely impair quality of life. We suggest that chemotherapy should be considered at an early stage in the more aggressive subtypes of non‐Langerhans cell histiocytoses.

The potential role of abnormal E-cadherin and α-, β- and γ-catenin immunoreactivity in the determination of the biological behaviour of keratoacanthoma

Backgroundu2003Failure of E‐cadherin and its associated proteins α‐, β‐ and γ‐catenin is believed to lead to disruption of cell–cell adhesion and to contribute to neoplasia.

Erythema gyratum repens and acquired ichthyosis associated with transitional cell carcinoma of the kidney.

Both erythema gyratum repens (EGR) and acquired ichthyosis are distinctive dermatoses which have strong associations with internal malignancy. EGR usually precedes the diagnosis of malignancy whereas acquired ichthyosis commonly manifests after the detection of malignancy. We report a patient who initially presented with a figurate eruption of EGR which later developed into a widespread ichthyosis with disappearance of the serpiginous rash. Further investigations revealed an underlying transitional cell carcinoma of the kidney, an association which has not previously been reported with either EGR or acquired ichthyosis. The occurrence of two paraneoplastic skin disorders in the same patient may be explained by tumour cell secretion of transforming growth factor alpha, which has been shown to be mitogenic for keratinocytes.

Xanthogranuloma is the archetype of non‐Langerhans cell histiocytoses: reply from author

s are invited for a 3-day symposium, Àdvances in Medical and Surgical Dermatology, to be held 79± December 2001 in New York, USA. Closing date for abstracts is 1 November, 2001. The timetable for the meeting is as follows: Friday December 7: Surgical meeting. Cutting edge lectures on all aspects of surgical and cosmetic dermatology: Saturday December 8: Live patient demonstrations of filler substances, Botox, laser treatments. Scientific meeting lectures by leaders in dermatological research. Prizes of