What's hot?
What's hot
June 27, 2019
In this monthly column, members of the Dermatology World Editorial Advisory Workgroup identify exciting news from across the specialty.
Mallory Abate, MD
Many dermatologists initiate a test dose of methotrexate, followed by laboratory evaluation prior to prescribing the second dose. However, is a test dose of methotrexate really necessary? A recent retrospective study — Initiation of methotrexate with or without a test dose: A retrospective toxicity study — demonstrates that laboratory evaluation after the test dose rarely leads to management changes and results in significantly more lab draws (J Am Acad Dermatol. 2019; 80(4): 1160-2). No difference in the incidence of methotrexate toxicity was found in patients initiated with and without a test dose. Thus, the authors conclude that this practice can be safely omitted in patients with normal renal function. The authors further note that data from clinical trials even suggest that starting doses of 15 to 17.5mg/week are associated with a low risk of serious adverse events.
Rosalie Elenitsas, MD
Approximately 25 to 50% of patients with chronic lymphocytic leukemia (CLL) develop non-specific or paraneoplastic dermatoses. Eosinophilic dermatosis of hematologic malignancy is one of these types of reactions. It is also termed insect bite-like reaction. While initially thought to be an exuberant reaction to insect bites, it is now accepted that insect bites are not the etiology. It was assumed that these patients had an altered immune response resulting in skin lesions containing many eosinophils. In a recent paper by Meiss et al (Journal of Cutaneous Pathology. 2019; 46(3): 175-181), the authors examined eight biopsies from five patients with eosinophilic dermatosis in patients with CLL. By immunohistochemistry, they noted up to 20% of the lymphocytes in the infiltrate were B cells. Additionally, IgH clonal rearrangements were noted in four of the five patients and three of them had identical clones to the patients’ known CLL clones. This suggests that the leukemic B cells may play a role in the pathogenesis of these skin lesions, and are not just simply “along for the ride.” In either case, dermatologists should be familiar with this entity, as patients may seek care for these persistent and refractory lesions.
Sylvia Hsu, MD
The commercially available bullous pemphigoid 180 (BP180) NC16A enzyme-linked immunosorbent assay (ELISA) is a test that can be used to aid in the diagnosis of bullous pemphigoid (BP). A result of > 9 U/mL is defined as a positive test. However, does a positive test necessarily mean the patient has BP? The answer is no. Circulating BP180 autoantibody can be detected in patients who do not have BP. In this study, the authors sought to determine an optimum cutoff value of BP180 ELISA to detect true BP. A total of 173 inpatients were included: 26 patients with BP and 147 patients in which BP was initially suspected, but later excluded (J Am Acad Dermatol. 2019; 80(3): 774-5). The titers of BP180 autoantibodies in non-BP patients were significantly lower than those of BP patients (median titer 17.1 U/mL versus 67.1 U/mL). Receiver operating characteristic curve [plot of sensitivity vs. (1 specificity)] analysis was used to generate paired sensitivity and specificity values based on BP180 autoantibody titers. The optimum cutoff value to determine true BP patients from non-BP patients was calculated on the basis of maximizing the Youden index (J = sensitivity + specificity 1). This optimum cutoff was found to be 27.2 U/mL, which has a sensitivity of 65.4% and a specificity of 98.0%, in contrast to the standard cutoff of 9 U/mL, which has a sensitivity of 73.1% and much lower specificity of 85.7%. These results show that low-level BP180 autoantibodies can be found in patients who do not have BP and the results of BP180 ELISA should be interpreted in conjunction with clinical findings and immunopathologic test results.
Kenneth A. Katz, MD, MSc, MSCE
I wish medical journals more often read like Consumer Reports. That’s not because I’m obsessed with consumer goods. (I’m not.) Rather, it’s because their approach — comparing goods or services within a category — is incredibly valuable to me as a consumer. I want to know how one vacuum cleaner stacks up against another, after all, not whether it beats a placebo.
By contrast, too often in medicine we get placebo-controlled trials, often done to obtain FDA approval for a new treatment. For conditions for which a treatment is available, trials like those arguably have little value for clinicians and patients seeking to choose between treatments.
Research that studies the comparative effectiveness of treatments is called, not surprisingly, comparative effectiveness research. A good example relevant to dermatology is a randomized trial of four treatments for actinic keratosis (N Engl J Med. 2019; 380:935-46).
Enrolling 624 participants who each had at least five clinically diagnosed AKs on the head, the trial investigated effectiveness of fluorouracil 5% cream, imiquimod 5% cream, methyl aminolevulinate photodynamic therapy (MAL-PDT), and ingenol mebutate 0.015% gel. The primary outcome — a 75% decrease in the number of AK lesions 12 months after treatment ended — was reached by significantly more participants who received fluorouracil (75%; 95% confidence interval [CI], 67% to 81%) compared with imiquimod (54%; 95% CI, 45% to 62%), MAL-PDT (38%; 95% CI, 30% to 45%), or ingenol mebutate (29%; 95% CI, 22% to 36%).
Bottom line: For AKs, fluorouracil appears to be the best vacuum.
