Rosenbach, Misha

Importance Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis characterized by sterile ulcerative skin lesions. Multiple comorbidities and clinical features have been associated with PG, but no standardized guidelines exist for classifying PG phenotypes. Objective To develop an expert-established classification framework for PG phenotypes to inform treatment guidelines and future research endeavors. Evidence Review In this modified Delphi consensus study that included 23 board-certified dermatologists and Medical Dermatology Society members with expertise in PG, panelists completed 5 rounds of anonymous, iterative online surveys that were administered from December 2023 through July 2025. Before the beginning of the consensus exercise, a literature review was performed by nonvoting researchers to summarize existing data on PG clinical associations and comorbidities. A PubMed search from inception to September 2023 identified observational studies, narrative reviews, systematic reviews, and meta-analyses describing PG clinical associations and comorbidities that were published in English. Experts indicated their agreement with proposed PG phenotypes and disease modifiers with a consensus threshold of 70% or greater. Anonymous comments and aggregated results were presented in each subsequent round. In the final round, a framework of PG phenotypes and disease modifiers was proposed for agreement. Findings Twenty-three board-certified dermatologists and Medical Dermatology Society members with expertise in PG completed 5 rounds of iterative surveys. Consensus was reached on the final set of PG phenotypes and disease modifiers, with 83% of experts in agreement. PG phenotypes were overall classified into 2 major groups: PG with autoinflammatory syndromes and nonsyndromic PG. Nonsyndromic PG included 4 phenotypes: inflammatory bowel disease–associated PG, PG in association with hematologic cancers and blood dyscrasias, drug-induced PG, and other (including idiopathic) PG. Disease modifiers of PG phenotype presentations included involvement of special sites (head/neck, genitals, or peristomal skin) and extracutaneous manifestations. Conclusions and Relevance This expert-established, descriptive framework provides a standardized classification system for distinct PG phenotypes and its modifiers. This nomenclature may inform upcoming clinical guidelines and allow for consistency in reporting epidemiological research and outcomes among patients with PG.

ImportanceMetastatic cutaneous Crohn disease (MCD) is a rare condition for which there are currently no published diagnostic criteria. Formal MCD diagnostic criteria will expand clinical care and research by enabling future diagnostic code validation, crystallizing a more uniform disease entity for the purposes of translational research, and allowing the development of more formalized outcome measures aimed at treatment response.ObjectiveTo define a set of criteria for the diagnosis of MCD.Evidence ReviewIn this consensus statement, a panel of experts on MCD and related conditions was assembled. Their opinions were gathered regarding the clinical and histologic findings that are sufficient, necessary, and highly suggestive of MCD through serial survey. Subsequent surveys were continued until consensus was achieved. Sufficient was defined as a feature that, if noted, would enable diagnosis of MCD without any other signs, symptoms, or testing. Necessary was defined as a feature that must be present to establish a diagnosis of MCD. Highly suggestive referred to any other features that were indicative of MCD but did not qualify as sufficient or necessary to diagnose MCD.FindingsOf 24 experts invited, 19 agreed to participate, with a 79% to 100% response rate across 5 rounds conducted. Five patients were also invited to participate, but none opted to participate, citing lack of clinical expertise and time concerns. The experts were all from the US; 5 (26%) have practiced medicine for 0 to 5 years, 5 (26%) practiced for 6 to 10 years, 6 (32%) practiced for 11 to 15 years, and 3 (16%) practiced for more than 20 years. A total of 18 experts (95%) worked in an academic practice setting. There was consensus agreement that MCD could present as oral disease, genital disease, or, rarely, in another location. Consensus was achieved on 2 major and 5 minor criteria for genital/other subtypes of MCD and 5 minor criteria for oral MCD. There was consensus that, while there are some pathological findings that are highly suggestive of MCD, histologic criteria are not necessary for diagnosis.Conclusions and RelevanceA panel of experts reached consensus on the diagnostic criteria for MCD described in this study. These criteria include major and minor clinical criteria, along with histopathological criteria for the diagnosis of genital and oral MCD. This consensus is a crucial step in the diagnosis of and future treatment development for MCD, a rare and clinically understudied condition.

AbstractBackgroundNecrobiosis lipoidica (NL) is a rare, idiopathic, and recalcitrant disease of collagen degeneration for which treatment options have been poorly studied. Due to its recurring nature, risk for ulceration, and high morbidity, there is a need to understand existing treatment modalities to better inform clinical care.ObjectiveThis review aims to describe the therapeutic modalities reported in the literature for the treatment of NL.MethodsA literature search of treatments was performed by searching for publications between January 2016 and May 2022 on PubMed and Scopus. Given the limited high‐quality evidence, case reports and series were included. Only publications presenting information on both attempted treatments and outcomes were included.ResultsA total of 60 novel articles were identified (54 case reports, two case series, and four retrospective cohort studies). These studies cumulatively reported on 274 patients and covered treatments including phototherapy, topical corticosteroids, topical calcineurin inhibitors, biologics, immunosuppressants, JAK inhibitors, combination therapies, and several others. The greatest amount of evidence was found for photodynamic therapy (improvement in 72 of 80 patients), UVA‐based phototherapy (12 of 33), topical corticosteroids (21 of 46), compression therapy (15 of 20), and topical calcineurin inhibitors (11 of 17). Several newer treatments were also described, including ustekinumab and JAK inhibitors.ConclusionsThis systematic review provides a comprehensive summary of recently published treatments for NL. As the existing data comes predominantly from case reports and series, statistical conclusions are not assessed. A greater number of randomized controlled trials with standardized endpoints are necessary to compare treatment efficacy.

Importance Scoring systems for Stevens-Johnson syndrome and epidermal necrolysis (EN) only estimate patient prognosis and are weighted toward comorbidities and systemic features; morphologic terminology for EN lesions is inconsistent. Objectives To establish consensus among expert dermatologists on EN terminology, morphologic progression, and most-affected sites, and to build a framework for developing a skin-directed scoring system for EN. Evidence Review A Delphi consensus using the RAND/UCLA appropriateness criteria was initiated with a core group from the Society of Dermatology Hospitalists to establish agreement on the optimal design for an EN cutaneous scoring instrument, terminology, morphologic traits, and sites of involvement. Findings In round 1, the 54 participating dermatology hospitalists reached consensus on all 49 statements (30 appropriate, 3 inappropriate, 16 uncertain). In round 2, they agreed on another 15 statements (8 appropriate, 7 uncertain). There was consistent agreement on the need for a skin-specific instrument; on the most-often affected skin sites (head and neck, chest, upper back, ocular mucosa, oral mucosa); and that blanching erythema, dusky erythema, targetoid erythema, vesicles/bullae, desquamation, and erosions comprise the morphologic traits of EN and can be consistently differentiated. Conclusions and Relevance This consensus exercise confirmed the need for an EN skin-directed scoring system, nomenclature, and differentiation of specific morphologic traits, and identified the sites most affected. It also established a baseline consensus for a standardized EN instrument with consistent terminology.