BackgroundElevated endotoxin levels have been measured in ambient air around livestock farms, which is a cause of concern for neighbouring residents. There is clear evidence that occupational exposure to high concentrations of airborne endotoxin causes respiratory inflammation, respiratory symptoms and lung function decline. However, health effects of exposure to low levels of endotoxin are less well described. The aim of this systematic review is to summarize published associations between exposure to relatively low levels of airborne endotoxin and respiratory health endpoints.MethodsStudies investigating respiratory effects of measured or modelled exposure to low levels of airborne endotoxin (average < 100 EU/m3) were eligible for inclusion. In total, 1362 articles were identified through a Pubmed database search, of which 31 articles were included in this review. Studies were included up to February 2017. Overview tables and forest plots were created, and study quality was assessed.ResultsTwenty-two included studies had a cross-sectional design, others were designed as longitudinal observational (n = 7) or experimental (n = 2) studies. Most studies (n = 23) were conducted in an occupational setting, some involved domestic or experimental exposure. Several studies reported statistically significant effects of exposure to low levels of endotoxin on respiratory symptoms and lung function. However, considerable heterogeneity existed in the outcomes of the included studies and no overall estimate could be provided by meta-analysis to quantify the possible relationship. Instead, a best evidence synthesis was performed among studies examining the exposure-response relationship between endotoxin and respiratory outcomes. Significant exposure-response relationships between endotoxin and symptoms and FEV1 were shown in several studies, with no conflicting findings in the studies included in the best evidence synthesis. Significantly different effects of endotoxin exposure were also seen in vulnerable subgroups (atopics and patients with broncho-obstructive disease) and smokers.ConclusionsRespiratory health effects of exposure to low levels of airborne endotoxin (< 100 EU/m3) seem plausible. Future studies are needed to investigate ambient exposure to endotoxin and potential respiratory health effects, especially in vulnerable subgroups of the population.Electronic supplementary materialThe online version of this article (10.1186/s12940-018-0360-7) contains supplementary material, which is available to authorized users.

BackgroundMulticentric reticulohistiocytosis is a rare form of non-langerhans cell histiocytosis presenting with skin changes and erosive arthritis. Infiltration of histiocytes and multinucleated giant cells are typical histological findings and confirm the diagnosis.Case presentationThis case report describes a newly diagnosed case of multicentric reticulohistiocytosis in a healthy 26-year-old female originally from the Philippines. Eruption of papules and nodules on the hands and pain in multiple joints were the main complaints at the initial presentation. Radiographical findings of erosions in the small hand and feet joints were impressive. Initial histological findings did not match the clinical image, although later the clinical diagnosis was supported by histological findings in additional biopsies.ConclusionsAlthough initial histological findings did not match the clinical image, additional biopsies were valuable to confirm the diagnosis.