Background
Description of the condition
Rhinitis and rhinosinusitis are part of a spectrum of inflammatory disorders of the respiratory tract. Rhinitis relates to the irritation or inflammation of the nasal mucous membrane, while sinusitis refers to inflammation of a sinus. The proximity between the sinus cavities and the nasal passages, as well as their common respiratory epithelia, lead to frequent simultaneous involvement of both structures. Rhinosinusitis refers to inflammation of the nasal cavities and sinuses (Desrosiers 2011) and is defined as an inflammatory condition of the nose and paranasal sinuses, characterised by nasal blockage, obstruction, congestion or discharge. It may be accompanied by facial discomfort or reduced sense of smell, supported by endoscopic signs of nasal polyps or mucopurulent discharge or mucosal oedema, primarily from the middle meatus. Mucosal changes within the osteomeatal complex and sinuses may also appear in a CT scan (Fokkens 2012). Rhinitis and rhinosinusitis can be allergic or non-allergic(Quillen 2006). Allergic causes include immune-mediated mechanism following exposure to various types of allergens such as dust mites, moulds or pollens, which may be seasonal or perennial. Non-allergic causes include non-immune-mediated mechanisms such as exposure to an irritant that is capable of inducing an inflammatory reaction of the airways (Meggs 1996).
Occupational factors are important contributors to adult rhinitis and rhinosinusitis, and these conditions are two to four times more prevalent than occupational asthma, which is another well-known illness in the same spectrum (Siracusa 2000). The workers at risk include laboratory workers, farmers, bakers, museum workers, textile workers, food-processing workers, healthcare workers, farmers, electronic or electrical products assemblers, and boat builders (Brisman 1999; Heederik 1999; Hytonen 1997; Kaukiainen 2008; Moscato 2009; Wiszniewska 2009). Generally, rhinitis and sinusitis are two expressions of the same underlying inflammatory disease of the respiratory mucosa, affecting more than 20% of the population in the United States and European countries (Bauchau 2004; Nathan 2008). Rhinosinusitis is highly prevalent in the United States, affecting an estimated 16% of the adult population annually (Anand 2004). Medical treatment has been used for both of these conditions. The effect of work-related rhinitis or rhinosinusitis in reducing workplace productivity are well documented (Crystal-Peters 2002; Fireman 1997; Vandenplas 2010), as are their impact on health care costs (Weiss 2001).
Work-related rhinitis (WRR) is an occupational disease defined by the European Academy of Allergy and Clinical Immunology (EAACI) as an inflammatory disease of the nose, which is characterised by intermittent or persistent symptoms (i.e. nasal congestion, sneezing, rhinorrhoea, itching), or variable nasal airflow limitation or hypersecretion due to causes and conditions attributable to a particular work environment and not to stimuli encountered outside the workplace (Moscato 2009; Önerci 2010). Work-related rhinosinusitis (WRRS) includes symptoms such as nasal blockage, nasal secretion, itching and sneezing after exposure to allergens or irritants, as well as facial pressure, headache, loss of sense of smell, nasal crust formation, dryness of the nose and nosebleeds. The presence of these symptoms are sufficient evidence for reaching a diagnosis of occupational rhinosinusitis (Hellgren 2008). WRRS symptoms can be triggered by a wide variety of conditions at work, which are categorised into annoyance (e.g. perfumes or detergents), irritational (e.g. cigarette smoke or capsaicin), corrosive (e.g. formaldehyde or ammonia) and immunologic (caused by high-molecular weight or low-molecular weight allergens such as psyllium and guar gum) (Slavin 2010; Thilsing 2012). Both WRR and WRRS include allergic and non-allergic components (Moscato 2011).
Common causes found at workplaces are irritants (e.g. chemicals, dusts, fumes), physical factors (e.g. temperature changes), socio-environmental factors such as secondhand smoke, strong smells (e.g. perfumes) and allergens (e.g. psyllium and guar gum) (Zhao 2012). Exposure to multiple agents have also been documented among workers exposed to cleaning agents, pesticides, inhalant allergens, paints and microbiological contaminants, with the prevalence of rhinitis ranging from 31% to 61% (Chatzi 2007; De Fatima 2007; Kaukiainen 2008; Park 2008; Riu 2008). WRR can affect workers' quality of life, work productivity and absenteeism (Szeinbach 2007), and overall productivity losses may range from 1% to 4%, while on-the-job effectiveness can decline by approximately 11% to 40% (Vandenplas 2010).
Description of the intervention
Workplace interventions for treating WRR or WRRS, which take place irrespective of any medical care a person might be receiving, may be more effective in alleviating symptoms than medical treatment alone. As the underlying cause of WRR and WRRS are agents present at the workplace, it would seem reasonable wherever possible to address these through secondary prevention approaches. Occupational health and safety professionals commonly use a framework called the hierarchy of controls (HIRARC) to identify risks and devise appropriate control measures. In general, the hierarchical levels used, from top to bottom, are elimination, substitution, engineering controls, administrative controls, training and education and personal protective equipment (PPE). Complete elimination of the causal agents can be implemented at some workplaces, but this is usually associated with substantial socioeconomic consequences (Vandenplas 2003), so it may be more feasible to remove workers from the source of exposure (Vandenplas 2002) or substitute causal agents with safer ones, for example by replacing powdered latex gloves with non-powdered ones (Filon 2006; Kelly 2011). Other exposure reduction measures that could be implemented at the workplace include engineering controls, administrative control and use of personal protective equipment. Engineering controls can be achieved by physical modification to a process or process equipment, or through the installation of further equipment (Ignacio 2006) to protect the workers from hazards, such as filters to capture and remove airborne emissions from exhaust ventilation. Limiting exposure by job rotation is one example of administrative controls; personal protective equipment such as ear plugs for noise reduction is considered the least effective measure. In one Cochrane review on workplace interventions, the authors conclude that complete removal from the exposure is more effective in improving asthma symptoms than reduction of the exposure (De Groene 2011). Any measures to treat WRR and WRRS are likely to be more effective in improving daily function and work productivity of the affected individuals if accompanied by a rehabilitation programme for patients who respond poorly to control measures.
How the intervention might work
The interventions might work differently depending on factors such as type or rhinitis (allergic or non-allergic), type of workplace environment and type of exposure at the workplace.
While the allergic (IgE-mediated) mechanism of WRR has been well-described, the mechanism of non-allergic WRR is still poorly understood (Schroer 2012). Obtaining detailed medical history, physical assesment and occupational records remain a key step in the investigation and diagnosis of WRR. Medical history is used to establish the timing of nasal symptoms, while the physical assessment gathers information on the nature, severity, and impact of WRR symptoms. Occupational history addresses duration of work (latency period), agents, tasks or processes associated with the onset or aggravation of symptoms, and it also notes improvements away from work (weekends or prolonged holidays) (Moscato 2009). This information helps in determining the causal agents and helps employers set up appropriate workplace intervention strategies.
Targeted interventions to treat symptoms of WRR or WRRS depend largely on the type of exposure. For example, for at-risk individuals who are sensitised in their occupations, such as cleaners who are exposed to various cleaning agents (De Fatima 2007), laboratory workers to animal fur and danders (Ferraz 2013), farmers to pesticides (Chatzi 2007), greenhouse workers to pollens and pesticides (Riu 2008), construction painters to paints and solvents (Kaukiainen 2008) and automotive manufacturing workers to microbes, endotoxins and metals (Park 2008), complete avoidance of the causal agents are recommended as the most effective therapeutic option (Moscato 2009). Allergen avoidance has known beneficial effects on improving health-related quality of life among workers exposed to bee pollen (Gerth 2011) and detergent enzymes (Adisesh 2011).
In certain high-risk individuals, allergen avoidance might need to be augmented with engineering control measures. Improvement of ventilation following the installation of high-efficiency air filters and electrostatic air cleaners that reduce the inhalable particles in the workplace decreases the likelihood of having work-related respiratory symptoms (Graudenz 2004; Skulberg 2005).
Job rotation, personal hygiene and good housekeeping are some of the examples of administration controls (Harrison 2001). It has been shown, for example, that training and raising educational awarenessare beneficial in reducing symptoms among farmers with occupational asthma (Dressel 2007).
Providing workers with personal protective equipment (PPE) is also part of intervention programmes to treat WRR and WRRS. The application of PPE ensures minimal exposure to allergens via all possible routes; PPE may include safety goggles for protecting the eyes or the entire face; gloves, aprons and boots for dermal protection; and face masks or air respirators for respiratory protection against allergens (HSE 2013).
However, there are also drawbacks of to using PPE, such as sensitisation to latex gloves. Avoidance of latex gloves would be the most straightforward method among workers with sensitisation to latex (Filon 2006), but other methods may be more feasible depending on the route of exposure. For example, in individuals sensitive to latex-aeroallergens, laminar flow helmet respirators are effective in reducing exposure to latex-allergic individuals (Laoprasert 1998). Helmet respirators have also shown to be partially effective in reducing the consequences of exposure in workers with WRR and asthma due to laboratory animals (Slovak 1985).
Why it is important to do this review
Work-related illnesses such as WRR and WRRS are problems of increasing magnitude (Moscato 2009). Several Cochrane reviews on pharmacological interventions for allergic rhinitis or related conditions have been published, including on the use of antibiotics (Arroll 2005), injection immunotherapy (Calderon 2007) and sublingual immunotherapy (Radulovic 2010). However, medical interventions targeting individuals have obvious limitations in reducing the incidence and severity of work-related conditions, and workplace strategies need to be evaluated rigorously in a systematic review that synthesises the best available evidence on current practice for stakeholders and health care decision makers and informs future research. To date, there has been no systematic review that evaluates non-pharmacological interventions instituted at the workplace with an aim to alleviate symptoms and shorten the recovery process from WRR or WRRS.