Occupation and Workplace Allergies
Allergies in the workplace are being more readily identified and are now a significant source of illness.
by Dr Adrian Morris
Occupational disease of the skin my take the form of allergic contact dermatitis from exposure to chromium in cement or be of the primary irritant type such as on exposure to benzene by motor mechanics. The nose may be affected by exposure to specific allergens such as wheat flour in Bakers, or non-specific irritants such as coal dust in miners. Among occupational diseases affecting the lungs, hypersensitivity pneumonitis affects farmers exposed to mouldy hay, miners exposed to silica and asthma in animal laboratory workers. Prompt intervention for suspected occupational allergies is most important as early detection may lead to reversibility of symptoms. Unfortunately once the disease is established, withdrawal from the offending environment may not necessarily lead to symptom improvement. Although medication and symptom control is important, the offending allergen must identified early and removed from the environment to prevent chronic ill health.
Occupational asthma is caused by sensitisation to an agent inhaled in the workplace and usually presents with cough, wheezing and variable shortness of breath. Symptom onset is slow and may only occur after years of repeated exposure to chemicals and allergens in the work environment. Two distinct types of occupational asthma occur namely Non-allergic Reactive Airways and Allergic Asthma. Allergic asthma takes longer to develop than non-allergic Reactive Airways Disease Syndrome (RADS) which may develop more rapidly due to workplace associated irritants such as chlorine , ammonia fumes or dust. Sometimes pre-exiting mild asthma is exacerbated in the workplace and smokers are more at risk for developing occupational asthma.
To date over 300 suspected causes for occupational asthma have been identified.
It is estimated that occupation induced asthma accounts for about 5% of the asthmatic population. This is possibly an under-estimate as many cases go permanently undetected. Occupational asthma occurs after repeated exposure to the offending allergen. Only a proportion of those exposed will develop asthma, and sensitivity usually increases over a period of time. Once sensitised, reactions may be triggered by exposure to minute quantities of allergen. In the early stages, symptoms will improve when away from the affected workplace over weekends or when on annual leave.
All factories and workplaces with potentially sensitising agents should be routinely inspected by occupational health physicians to monitor preventative measures and assessing air samples. Environmental control measures include the use of ventilated spray-paint booths, extractor fans, protective clothing, masks, respirators and visors. Sensitised workers should be removed from the offending environmental agent and the workplace modified to accommodate them or else they should be relocated to another work area that is unaffected. It is estimated that within a year of starting employment, 5-10% of animal handlers, 10% of Isocyanate workers and 30% of platinum workers develop symptoms of occupational asthma.
Workers in high risk areas should have routine checks for work related allergic sensitisation by means of Skin Tests, Lung Function Testing and be educated about possible risks of exposure. Lung function tests should be performed at work and then at again home to identify work related asthma. For an accurate assessment, this might necessitate 2 weeks of twice daily Peak Flow testing while at work, followed by 2 weeks testing off work and then 2 weeks testing back at work. Occasional bronchial challenges are performed using the suspected allergen or methacholine.
Those most at risk include manufacturers of foam, plastics, varnishes and spray-paints which contain Isocyanates. Electronics with exposure to solder fumes (colophony), Hospital sterilisation procedures (glutaraldehyde), Hairdressers exposed to perm agents (persulphates). Platinum-refining workers (platinum salts). Bakers asthma in those exposed to flour dust and amylase enzyme. Those involved in manufacture of Epoxy resins, plastics and glues (acid anhydrides). Organic Dust exposure from Exotic Wood, Soya and Plant Grains,
Occupational Rhinitis or Nasal Allergies
Work related sneezing, nasal discharge and obstruction should alert one to possible occupational disease. The onset of symptoms may be similar to occupational lung disease occurring after prolonged and repeated exposure to the offending allergen. Quite often Occupational Rhinitis may precede occupational asthma, thus early diagnosis of occupational rhinitis may enable the employee to avoid further exposure and prevent the development of asthma. Nasal challenge testing may need to be performed to identify the causative agent. Non-allergic Irritant occupational rhinitis may occur after exposure to coal dust, talc, chlorine and cold air.
Occupational Dermatitis or Skin Allergies
Occupational Dermatitis is by far the most common cause of occupational disease and accounts for most workdays lost. Contact dermatitis makes up the majority of work related diseases, mostly in the form of non-allergic irritant dermatitis. Allergic contact dermatitis is becoming more prevalent and accounts for 20% of work related skin disease. Those occupations most at risk include:
Florists: Primula, Ivy, Lilies
Nurses: Latex, Iodide, formaldehyde
Builders: Chromate in cement
Hairdressers: Paraphenylenediamine in dyes
Printers: Acrylic dyes
Latex allergy is a relatively “new “ allergy and is most frequent in hospital medical staff exposed to latex rubber in gloves, catheters, drip sets, but also occurs in patients who have had numerous operations and surgical procedures. The most common source of sensitisation is exposure to the latex containing powder in latex gloves. It is imperative that latex allergic patients inform the hospital on admission, so that special precautions can be taken to prevent latex exposure during an operation or whilst on the ward.
In addition to medical and hospital equipment, Latex can be also found in baby bottle nipples and dummies, condoms, gloves, adhesive tape, carpets, chewing gum, balloons, goggles, hot water bottles, elastic in clothes, scuba diving wetsuits and rubber grips, boots, toys and tyres. See UK website of the LASIX ALLERGY SUPPORT GROUP for more useful information on Latex allergy and avoidance.
There are additional problems with allergic cross-reactivity to certain fruits. Latex sensitised people may develop allergies to Kiwi fruit, Avocado, Banana and Chestnuts amongst other fruits. Latex allergy may present with itchy rashes, asthma, rhinitis and even full blown anaphylaxis with death.
Nowadays Latex allergy can readily be identified with a simple blood test. Patients sensitive to latex should wear a medic alert bracelet, inform their doctor, dentist or gynaecologist, and carry injectable adrenaline and antihistamine medication.
Points to consider in suspected Occupational Allergy
- Where do you work?
- What exactly does your job involve?
- Is your asthma worse at work or in the early evening?
- Do you symptoms improve over weekends or when you are away from work on leave?
- Do you regularly get exposed to chemicals, paint, dust or fumes at work?
- Are you repeatedly exposed to high levels of these agents on a daily basis?
- Are other people at work similarly affected with symptoms?
Choosing a job, what are the high risk occupations for developing occupational allergies?
- Bakers and flour mill workers
- Food processing with exposure to Soya beans, fish, shellfish and egg
- Farmers, dockworkers and cotton workers from mould spores, poultry and plant dusts
- Carpenters and wood workers can become sensitised to exotic hardwoods
- Detergent and pharmaceutical factory workers exposed to enzymes, medication and biological dusts
- Hospital workers exposed to powdered latex gloves and formaldehyde such as theatre nurses, cleaners and surgeons
- Laboratory workers exposed to airborne animal allergens
Occupational Allergy and the Law
Under the Health and Safety at Work Act of 1974, employers are legally obliged to protect the health and safety of their employees. The Control of Substances Hazardous to Health Regulations (COSHH 2002) requires organisations to assess risks capable of causing occupational illnesses. Employers have a statutory obligation to report suspected occupational illnesses (Reporting of Injuries, Diseases and Dangerous Occurences Regulations 1995). The local Department of Social Security in the UK will provide booklets and BI 100(OA)forms for patient eligible to claim compensation for work related illnesses including asthma (Booklet: Occupational Asthma NI 237)