PracticeUpdate Dermatology Best of 2018

TOP STORIES 2018 9

Comprehensive Patch Testing for Contact Dermatitis By Christen Maria Mowad MD C ontact dermatitis has been identified as the fifth most common skin disease in the US, affecting more than 13 million Amer- icans of all ages and races, and accounting for $1.529 billion in healthcare expenditures. Until the causative allergen is identified, aller- gic contact dermatitis will remain a chronic disease with numerous quality-of-life issues and significant eco- nomic and personal costs to individuals and society. With a delay in diagnosis or an incorrect or incomplete diagnosis, the eruption continues indefinitely. Comprehensive patch testing is essential to accurately identify causative allergens, resulting in resolution and prevention of disease. ACD can be cured in most cases with the identification of the causative allergen and proper education regarding identification and avoidance of these allergens in the environment. Although FDA-approved allergen series with limited, static numbers of aller- gens are available, these can have limited diagnostic capacity and have been shown to detect at best 66% of relevant reactions. Comprehensive patch testing is needed to accurately and more fully identify causative allergens. A paper entitled, “The Medical Necessity of Comprehensive Patch Testing,” outlines the benefits and necessity of compre- hensive patch testing. 1 History, physical examination, and a query of personal care products, work exposures, avocations, as well as other daily contactants, help direct allergen selection for testing. Expanded/supplemental allergen testing series have been shown to improve diagnostic yield, resulting in better chances at a cure of what would otherwise remain a chronic disease. Patch testing is the criterion standard for diagnosing and resolv- ing allergic contact dermatitis. The limitations on the number of allergens tested hinders the ability to identify causative allergens and limits our ability to potentially cure a chronic disease with sig- nificant costs both economically and personally to patients and society. This paper is important as it highlights the value of compre- hensive patch testing and its ability to diagnose and help resolve a significant and costly skin problem. As limitations on this valua- ble tool are increasingly being imposed, this paper outlines why comprehensive patch testing is of significant value and needs to remain a tool for detection and management of one of the most common skin diseases in the United States. Reference 1. Zhu TH, Suresh R, Warshaw E, et al. The Medical Necessity of Comprehensive Patch Testing. Dermatitis 2018;29(3):107-111. www.practiceupdate.com/c/76154 " …comprehensive patch testing is of significant value and needs to remain a tool for detection and management of one of the most common skin diseases… "

• There were no significant differences in the 5-year RFS, with 60.9% in the observation group compared with 59.9% in the CLND group. • A subgroup analysis was performed based on tumor load in the SLNB: x x The DMFS rate differed between those patients with a SLNB tumor load ≤1.0 mm versus those with a SLNB tumor load >1 mm, but not between the observation and CLND treatment groups. x x The 5-year DMFS for those with a SLNB ≤1.0 mm was 72.5% in the observation group versus 68.7% in the CLND group; the data for those with a SLNB with a metastasis of >1mm was 51.7% (observation group) versus 54.7% (CLND group). x x The 5-year lymph-node recurrence-free survival was 65% (observation group) vs 65.9% (CLND group). The authors performed a multivariable analysis, demonstrat- ing that tumor thickness and tumor load in the SLNB were independent prognostic factors for DMFS, OS, and RFS. In the conclusion of the presentation, the authors stated that “immediate CLND in SLNB-positive patients is not superior to observation. We would no longer recommend CLND in patients with micro-metastases.” This is a major change in what was previously recommended and will spare our patients the morbidity of a CLND for those who have a micro-metas- tasis on SLNB. References 1. Eggermont AMM, Blank CU, Mandala M, et al. Adjuvant pembrolizumab versus placebo in resected stage III melanoma. N Engl J Med 2018;378(19):1789-1801. 2. Tawbi HA, Forsyth PA, Algazi A, et al. Combined nivolumab and ipilimumab in melanoma metastatic to the brain. N Engl J Med 2018;379(8):722-730. 3. Leiter UM, Stadler R, Mauch C, et al. Final analysis of DECOG-SLT trial: survival outcomes of complete lymph node dissection in melanoma patients with positive sentinel node. J Clin Oncol 2018;36(15_suppl):9501. 4. Nam J. Complete lymph node dissection may not improve outcomes in melanoma. Can Ther Adv Published June 4, 2018. Accessed November 5, 2018. www.practiceupdate.com/c/75706

VOL. 2 • NO. 4 • 2018