Our finding of frequently reported respiratory symptoms suggests a need for additional studies on exposed workers in this field.

The aim of this study was to determine concentrations of particulates and volatile organic compounds (VOCs) emitted from 3D printers using polylactic acid (PLA) filaments at a university workroom to assess exposure and health risks in an occupational setting. Under typical-case (one printer) and worst-case (three printers operating simultaneously) scenarios, particulate concentration (total and respirable), VOCs and formaldehyde were measured. Air samples were collected in the printing room and adjacent hallway. Size-resolved levels of nano-diameter particles were also collected in the printing room. Total particulate levels were higher in the worst-case scenario (0.7 mg/m 3 ) vs. typical-case scenario (0.3 mg/m 3 ). Respirable particulate and formaldehyde concentrations were similar between the two scenarios. Size-resolved measurements showed that most particles ranged from approximately 27 to 116 nm. Total VOC levels were approximately 6-fold higher during the worst-case scenario vs. typical situation with isopropyl alcohol being the predominant VOC. Airborne concentrations in the hallway were generally lower than inside the printing room. All measurements were below their respective occupational exposure limits. In summary, emissions of particulates and VOCs increased when multiple 3D printers were operating simultaneously. Airborne levels in the adjacent hallway were similar between the two scenarios. Overall, data suggest a low risk of significant and persistent adverse health effects. Nevertheless, the health effects attributed to 3D printing are not fully known and adherence to good hygiene principles is recommended during use of this technology.

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Chlorhexidine is a synthetic biguanide used as an antiseptic in hospital and household products. Chlorhexidine exposure has been implicated in various hypersensitivity reactions, including allergic contact dermatitis, fixed drug eruptions, occupational asthma, generalized urticaria and anaphylaxis. 1 Perioperative anaphylactic reactions to chlorhexidine have been reported since the 1990s and are typically caused by chlorhexidine-containing lubricants for in-dwelling urinary catheters, chlorhexidine-coated central venous catheters (CVCs) and topical chlorhexidine application. 2 Up to 9% of cases of IgE-mediated perioperative anaphylaxis in the UK have been attributable to chlorhexidine; a similar figure has been reported by a Danish study. 3,4 Since 1998, the US Food and Drug Administration has communicated the risk of serious hypersensitivity reactions to chlorhexidine. Notably, patients may exhibit early, unrecognized features of chlorhexidine sensitization prior to development of anaphylaxis. Guleri et al described three patients exhibiting pruritic rashes after topical chlorhexidine exposure who developed anaphylactic shock after insertion of a chlorhexidine-coated CVC. 5 In the dialysis setting, chlorhexidine is used for disinfection of skin and catheter exit sites for arteriovenous fistulas. A recent case series from a Canadian tertiary care centre of haemodialysis patients who developed life-threatening anaphylaxis induced by chlorhexidine-coated CVCs during renal transplantation suggested dialysis patients as an at-risk population. 6 Haemodialysis patients have previously reported rates of perceived chlorhexidine hypersensitivity from 12% to 23%. 7 Frequent chlorhexidine exposure could predispose both dialysis patients and staff to allergic sensitization.The purpose of our study was to assess the prevalence of chlorhexidine skin allergy symptoms and chlorhexidine sensitization in patients and staff in a dialysis setting. | ME THODSNurses and patients were recruited from haemodialysis units at the Toronto General Hospital from June 2018 through August 2018.Consenting participants were administered a questionnaire regarding chlorhexidine exposure history, allergic symptoms to chlorhexidine, and atopic history (Supplementary Material) and offered chlorhexidine skin prick testing (SPT). Serum samples were requested from participants with symptoms suggestive of chlorhexidine allergy or positive SPTs for measurement of serum specific IgE (sIgE) to chlorhexidine (ImmunoCAP, Phadia AB). Positive test criteria included SPT chlorhexidine weal diameter ≥3 mm with concordant positive control (histamine 1 mg/mL) and negative control (glycerinated phenol 0.9% saline) at 10 minutes, and/or sIgE >0.35 kUA/L. Reactions to chlorhexidine were classified as likely contact urticaria/pruritus, possible contact urticaria/pruritus or a rash/pruritus occurring more than 3 hours after chlorhexidine contact (Table 2 footnotes).Chlorhexidine skin allergy was defined as having a clinical history suggestive of chlorhexidine-associated ...

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treatments. 2 In contrast to systemic symptoms, this subset of patients with dermatomyositis is characterized by milder inflammatory cutaneous manifestations, usually associated with calcinosis cutis and peripheral edema. Skin disease remission is easier to achieve in these patients 2 compared with those who have long-standing systemic symptoms.In this observation, we describe a rare case of dermatomyositis with Degos-like skin lesions. To our knowledge, the literature contains few other reports of analogous cutaneous manifestations in connective tissue diseases, including dermatomyositis, systemic lupus erythematosus, and systemic sclerosis. 3,4 This case report describes a specific manifestation of dermatomyositis and a phenotypic overlap: both a Degos disease-like presentation and NXP-2 antibodies are indicative of vascular injury with involvement of the gastrointestinal tract. 5,6 Therefore, this case report stimulates future speculation about the interplay between inflammation and autoimmunity, which could translate into a new skin phenotype.

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