A double-blind randomized placebo-controlled pilot study comparing topical immunomodulating agents and corticosteroids for treatment of experimentally induced nickel contact dermatitis.

BACKGROUND: Although topical glucocorticoids are effective for most inflammatory skin disorders, their use is limited by local and systemic side effects. Tacrolimus and pimecrolimus are immunomodulators that provide clinicians with steroid-sparing options in the long-term topical treatment of allergic contact dermatitis. OBJECTIVE: To obtain pilot data regarding the relative efficacies of pimecrolimus 1% cream, tacrolimus 0.1% ointment, clobetasol propionate 0.05% ointment, and triamcinolone acetonide 0.1% ointment, as compared to control preparations (Vanicream and petrolatum), for treatment of experimentally induced nickel contact dermatitis. METHODS: Twenty-one volunteers with positive patch test reactions to nickel sulfate 5% at six sites (three on each arm) applied each study medication to one nickel site, respectively, twice daily for 14 days. Study medications were prepared in identical syringes, and the site of application was randomly assigned by a computer-generated randomization schedule. Assessments were performed at 3, 7, 10, and 14 days after randomization. RESULTS: Most reactions were coded as resolved or as almost resolved by day 14 regardless of treatment. Although most pairwise comparisons were not statistically significant, a clear trend was observed for sites treated with active drug to do better than control sites. CONCLUSION: Possible explanations for these results include contamination by neighboring medication sites, timing of assessments, and lack of repeated nickel applications.

Optimizing reproducibility for clinical studies involving patch testing and application of topical preparations.

BACKGROUND: The reproducibility and consistency of patch-test techniques can be problematic, making controlled clinical trials of patch testing difficult. OBJECTIVE: To measure the accuracy and reproducibility of applying controlled quantities of petrolatum onto Finn Chambers. METHODS: Four dermatology nurses applied a total of 240 samples of white petrolatum, using three syringe sizes and types. Three different amounts of white petrolatum (0.02 mL, 0.05 mL, and the "usual" amount) were expressed onto previously weighed Finn Chambers, using three different syringe sizes (5 mL, 1 mL, and 0.5 mL), five times each on two separate days. RESULTS: The average weights of 0.05 mL of petrolatum expressed with each type of syringe (5 mL: 0.04252 g; 1 mL: 0.04084 g; and 0.5 mL: 0.04139 g) were not significantly different from each other in pairwise comparisons (p > .36) or from the "gold standard" expected value (0.04138 g, p > .72). The average weights of 0.02 mL of petrolatum expressed with two types of syringes (5 mL: 0.02138 g; 0.5 mL: 0.01778 g) were significantly different from each other (p = .0012), but neither differed significantly from the expected value (0.01655 g, p > .08). The variance due to the effect modifications of nurse, day, and interaction of nurse and day was statistically significant for measurements made with the 5 mL syringe but not for measurements made with the 1 mL or 0.5 mL syringe. CONCLUSION: The average amounts of petrolatum extruded from smaller syringes (0.5 mL and 1 mL) were less variable and more reproducible than those extruded from a 5 mL syringe.

Mohs micrographic surgery for lentigo maligna and lentigo maligna melanoma using Mel-5 immunostaining: University of Minnesota experience.

BACKGROUND: Mohs micrographic surgery (MMS) continues to become a more common and accepted treatment for lentigo maligna (LM) and lentigo maligna melanoma (LMM). The primary difficulty encountered lies in the accurate identification of atypical single melanocytes to determine tumor-free margins. Numerous methods have been used to better visualize single melanocytes, with varying results. We present our experience using Mel-5 immunostaining in MMS of LM and LMM. METHODS: Two hundred patients with primary or recurrent LM or LMM were treated using MMS from 1999 to 2003 at the University of Minnesota. The initial clinical margins were determined by Wood's light examination, and an initial debulk specimen was taken and sent for formalin fixation and later reviewed by a dermatopathologist. The first Mohs layer was then taken, and staining with hemotoxylin and eosin as well as Mel-5 immunostaining was performed. All patients were followed up to evaluate for recurrence, with a mean follow-up time of 38.4 months. RESULTS: Of the 200 patients treated, only one recurrence was noted. This patient had been treated with excision followed by radiation before MMS. Use of Mel-5 immunostaining added approximately 40 minutes to each stage. Use of the Autostainer Immunostaining System (DAKO, Carpenterina, CA, USA) shortened the added time to 20 minutes. CONCLUSIONS: MMS with Mel-5 immunostaining yielded excellent results in the treatment of LM and LMM, with only one recurrence noted in 200 patients. When an automated immunostainer was used, minimal time was added to each Mohs stage.

Lasers and light therapy for acne vulgaris.

Acne vulgaris remains an emotionally and debilitating dermatologic disease, and is conventionally treated with a variety of oral and topical therapies with a number of significant side effects. An evolving understanding of laser-tissue interactions involving Propionibacterium acnes-produced porphyrins, and the development of infrared nonablative lasers to target sebaceous glands, has lead to the development of an escalating number of laser, light and radiofrequency devices for acne. Used as monotherapy or in combination, these devices are showing promise as a method to clear acne in a convenient, non-invasive manner, though there remains a clear need for long-term data and randomized, blinded studies.

Statistical significance and clinical relevance: the importance of power in clinical trials in dermatology.

When evaluating the validity of a study, the reader must consider both the clinical and statistical significance of the findings. A study that claims clinical relevance may lack sufficient statistical significance to make a meaningful statement. Conversely, a study that shows a statistically significant difference in 2 treatment options may lack practicality. The concept of power of a clinical trial refers to the probability of detecting a difference between study groups when a true difference exists. We will discuss statistical power by examining studies too small to identify important differences, studies so large as to identify differences that are not clinically significant, difficult-to-design studies without very large patient populations, and those studies with both adequate power and clinically relevant findings. Dermatologists should not focus on small P values alone to decide whether a treatment is clinically useful; it is essential to consider the magnitude of treatment differences and the power of the study.