No abstract

Importance Systemic sclerosis (SSc) is a severe, chronic, and incurable autoimmune fibrotic skin disease with significant extracutaneous involvement. Low concordance rate in twin studies and unequal geographic distribution of SSc argues for importance of environment in disease initiation and progression. Objective In this manuscript we provide a summary of all investigated potential external risk factors for SSc. Data sources A literature search in PubMed and EMBASE database was performed for studies published until January 1, 2020 by 2 reviewers (EN and LO) independently. Findings Occupational and/or environmental exposures to silica and organic solvents are associated with increased incidence and severity of SSc. Exposure to epoxy resins, asbestos, and particulate air pollution favors increased risk of SSc, but data are based on limited number of observational studies. There is insufficient evidence to conclude an association between SSc development and other occupational (eg, welding fumes) or personal exposures (eg, smoking, vitamin D deficiency). Association of SSc with silicone breast implants has been disproven. Infectious pathogens (eg, Helicobacter pylori and angiotropic viruses) and dysbiosis seem to play a role in SSc development and severity, but their role remains to be clarified. Conclusions and relevance It may be prudent to counsel our patients with SSc (or those at risk of SSc) to avoid occupations with exposure to silica, organic solvents, asbestos and epoxy resins; restraint from smoking, using cocaine or drugs with pro-fibrotic potential. While the association between low vitamin D and SSc remains to be confirmed, we believe that SSc patients should be encouraged to maintain healthy vitamin D levels as benefits outweigh the risks.

Bullous pemphigoid (BP) is an autoimmune blistering skin disease. Current treatment strategies are limited by their efficacy and/or side effect profile and the need for safer and effective alternatives is undeniable. We aimed to conduct a systematic review focusing on the efficacy and safety of omalizumab in BP patients. Embase, PubMed, Cochrane, and clinicaltrials.gov were searched for English and French articles published from inception to July 1, 2021, using search terms “omalizumab” OR “Xolair” OR “IGE025” OR “olizumab” AND “bullous pemphigoid.” Screening and data extraction was performed by two raters independently. The primary outcome was complete response (CR), and secondary outcomes were partial response (PR), flare-ups, adverse events/vital status. In total, 22 articles were included, with a total of 56 patients. All patients had a refractory BP with mean disease duration of 13.5 ± 20.2 months (Standard Deviation (SD)) and failed 3.1 ± 1.6 therapies and many remained corticosteroids dependent. Overall, 87.5% of patients responded to treatment (55.4% CR and 32.1% PR), 7.1% discontinued the protocol and only 5.4% were non responders. A third of patients were able to discontinue all other therapies and most others were able to discontinue or taper systemic corticosteroids to <10 mg daily. Flare-ups occurred in 57.7% of patients upon discontinuation of omalizumab and/or steroid tapering, most patients recaptured response thereafter. Omalizumab was well tolerated by most patients. Omalizumab appears to be a promising treatment for BP with a good response rate and safety profile. However, several limitations were identified in current literature, and highlight the need for randomized controlled trials of omalizumab in BP.