Common Occupational Allergies: Where Do We Stand?Rakesh Nair MD, Karina Villalba, Deepa Dillikar MD, Shafia Rubeen MD, Indu Prasadh MD and Janvier Gasana MD, PhD

Department of Environmental and Occupational Health, Robert Stempel School of Public Health, Florida International University, Miami, FL

Common Occupational Allergies: Where Do We Stand?Rakesh Nair MD, Karina Villalba, Deepa Dillikar MD, Shafia Rubeen MD, Indu Prasadh MD and Janvier Gasana MD, PhD

Department of Environmental and Occupational Health, Robert Stempel School of Public Health, Florida International University, Miami, FL

BACKGROUND: Allergies in the workplace are being more readily identified

and are now a significant source of illness.  Occupational disease of the skin may

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

moldy 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 are important, the

offending allergen must be identified early and removed from the environment to

prevent chronic ill health.

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 evenings? Do your symptoms improve over weekends or when you are away from workplace 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 workplace similarly affected with symptoms?

Common Occupational Settings With Exposure To Hazardous Biological Agent

SECTOR EXAMPLESAgriculture • Cultivating, harvesting, forestry

• Breeding and tending animals, fishingAgricultural products • Abattoirs, food processing plants

• Storage facilities: grain silos, tobacco• Processing animal hair, leather, silk• Textile plants, sawmills, paper-mills

Animal care • Veterinary facilities, pet shopsBiotechnology/ • Production, microbiology, animal unitsresearch labs Metal • Metal working, solderingMining • Gold and coal miningHealth care • Hospitals, clinics, nursing homesPharmaceutical • Production of drugs, herbal productsSewage and • Waste removal, treatment plantswaste disposal

Chronic bronchitisChronic obstructive lung disease

Hypersensitivity pneumonitis(extrinsic allergic alveolitis)

Rhinitis, conjunctivitis, urticariaAsthma

Asthma-like syndrome (acute functional respose)

Toxic pneumonitisOrganic toxic dust syndrome

(fever, myalgia, headache, respiratory symptoms)

Inhalation fever(fever, myalgia, fatigue

Infections (including zoonosis)

Contact irritant dermatitisContact allergic dermatitisProtein contact dermatitis

Carcinoma (eg. nasopharynx, liver, lung)

Occupational Diseases

Latex Allergy

•Latex allergy is an important health problem for health care workers, long-term avoidance of natural rubber latex [Hevea brasiliensis (Hev b)] is currently recommended for health-care workers (HCWs) with established natural rubber latex (NRL) allergy.

•All studies done demonstrated the reduction of symptoms and incidence sensitisations after the changeover to a powder- free environment and the avoidance of unnecessary glove use.

•A Recent study found that latex allergy was in 4.32% (range, 4.01% to 4.63%) of health care workers HCWs and in 1.37% (range, 0.43% to 2.31%) of the general population. Also HCWs exposed to latex showed an increased risk of hand dermatitis (odds ratio [OR], 2.46; 95% CI, 2.11-2.86), asthma or wheezing (OR, 1.55; 95% CI, 1.15-2.08), rhinoconjunctivitis (OR, 2.73; 95% CI, 1.97-3.81), and at least one generic symptom (OR, 1.27; 95% CI, 1.09-1.47). In addition sensitization to latex was significantly associated with asthma and rhinoconjunctivitis

•Health care workers have an increased risk of sensitisation and allergic symptoms to latex but the use of un-powdered latex gloves by all workers and use of non-latex gloves by sensitized subjects can reduce symptoms and prevent new sensitisation.

Contact Dermatitis/ Urticaria/ EczemaOccupational dermatitis is by far the most common cause of occupational disease and accounts for most workday lost. •Occupations are: Florists (primula, ivy and lilies), Nurses (latex, iodine, formaldehyde), builders (chromate, cement), hairdressers (paraphenylene-diamine in dyes) and printers (acrylic dyes). •The diagnosis is often clinical, and may only be possible after the exclusion of allergic contact dermatitis with patch testing.

Eczema: Dry chapped hands seemed to be a problem in 33.1%, mainly among nurses, assistant nurses and laboratory assistants. Technicians and X-ray assistants(38%) and kitchen workers (35.7%) claimed to suffer significantly more from hand eczema than others.

Contact urticaria: The term contact urticaria (CU) describes a wheal-and-flare response elicited within 30-60 min after exposure to certain agents, that disappears within 24 hours. Sometimes, the symptoms are: itching, burning or tingling, alone or accompanied by erythema.The whealing reactions can be strictly confined to the area of contact but they can also appear as generalized urticaria,sometimes associated with extra cutaneous symptoms (bronchospasms, rhinoconjunctivitis, swellings of the upper airways, gastro-intestinal manifestations) and anaphylactic reactions. The severity of clinical reactions can be classified according to the system of Von Krogh and Maibach.

•Foods are the most frequent eliciting agents. Plants, animal products, drugs, cosmetics, industrial agents are also elicitors of immunologic contact urticaria (CU) recently published studies have demonstrated that an IgE mediated reaction is involved in most contact urticaria is produced by thaumetopoea Pityocampa. A high rate of sensitization and clinical allergy to latex has been reported in health care personnel, with prevalence rates up to 17% in the United States.

Occupational Rhinitis

•Rhinitis is one of the most common occupational diseases, 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.   

•The diagnosis of occupational rhinitis should be considered when sneezing, rhinorrhoea or nasal obstruction are associated with work.Occupational rhinitis is defined as exposure in the workplace to high-molecular-weight (HMW) agents, low-molecular-weight (LMW) agents and irritant substances through immunological or non-immunological pathogens, this condition frequently coexists with occupational asthma. However, if exposure to the offending agent persists, occupational rhinitis may develop into asthma.

•A recent study measured the relative risk of occupational rhinitis in different occupations and was expressed as the age-standardized rate ratio (SRR) The findings showed greatest risk of occupational rhinitis among furriers (SRR = 30.0), followed by bakers and livestock breeders (SRR = 22.0), food-processing workers, veterinarians, farmers, assemblers of electrical, electronic and tele-communication products, and boat builders were also at increased risk (SRR ranging from 7.3 to 13.0).

•Another study showed that occupational rhinitis may be connected to asthma with predictive aspects in bakers' disease.

Occupational Seafood Allergy•Workers involved in either manual or automated processing of crabs, prawns, mussels, fish, and fishmeal production are commonly exposed to various constituents of seafood.

•Aerosolisation of seafood and cooking fluid during processing are potential occupational situations that could result in sensitisation through inhalation.

•Occupational dermal exposure occurs as a result of unprotected handling of seafood and its byproducts.

•Occupational allergies have been reported in workers exposed to arthropods (crustaceans), molluscs, pisces (bony fish) and other agents derived from seafood. The prevalence of occupational asthma ranges from 7% to 36%, and for occupational protein contact dermatitis, from 3% to 11%.

•These health outcomes are mainly due to high molecular weight proteins in seafood causing an IgE mediated response. Disruption of the intact skin barrier seems to be an important added risk factor for occupational protein contact dermatitis.

•Skin prick tests and blood test for specific IgE antibodies were positive for many kinds of seafood, including sole, horse mackerel, sea eel, eel, crab, and abalone, which belonged to different taxonomic phyla, including Chordata, Arthropoda, and Mollusca.

•Oral allergy syndrome (OAS) is a complex of symptoms induced by exposure of the oral and pharyngeal mucosa to food allergens. It is seen in persons sensitized by direct hand contact with raw fish. Clinical symptoms and positive prick-by-prick test to raw fish confirms the diagnosis of OAS.

•The prevalence of dry skin, itching, rash/eczema, chapped skin and chronic sores is significantly higher among production workers in the white fish-, shrimp and salmon processing industries compared to administrative workers.

How Can we Prevent or Control Occupational Allergy (OA)?

Primary preventive measures: These measures can potentially include: (i) Identification of highly susceptible workers and locating them to areas without exposure to known sensitizers.

(ii) Limitation of exposure to potential respiratory irritants among those with pre-existing asthma to reduce work-related aggravation of asthma.

(iii) Use of engineering controls, such as elimination of a responsible agent, substitution with a safer substance/chemical, ventilation, process or equipment modification, process enclosure, dust reduction techniques, housekeeping and work practices.

(iv) Administrative controls to reduce number of workers exposed or duration of exposure, e.g. job rotation, rest periods, shift or location changes where fewer people are working with sensitizers or irritant exposures.

(v) Personal protective equipment (at the worker level), which includes respirators, gloves, goggles and coveralls.

Secondary preventive measuresAimed at detecting indicators of early sensitization or early changes of sensitizer-induced OA before there is permanent disease. This identification and early intervention with removal from further exposure can prevent permanent asthma.

Tertiary preventive measuresAimed at limiting medical impairment among those with established OA.

(i) For those with irritant-induced asthma, it has been suggested that early treatment with oral corticosteroids may improve long-term prognosis . For patients with persistent asthma induced by irritants, standard asthma management modalities, such as patient education, limitation of non-occupational irritant exposure and relevant allergen exposure as well as pharmacologic management as for non-occupational asthmatics, should be utilized

ii. For workers with sensitizer-induced OA, the best prognosis generally requires complete avoidance of re-exposure to the sensitizing occupational agent and any immunologically cross-reacting agents, in addition to standard asthma management.

Dermatitis/Eczema

Urticaria/bommels/wheals

Future Goal

•The evidence base continues to grow in relation to occupational asthma. Current areas of particular interest include novel agents, mechanisms of sensitisation and the health effects associated with complex multiple exposures. In addition, the diagnostic process in occupational asthma and choice of the most appropriate investigations is the subject of current debate •Future studies could better document the. true incidence of occupational allergic sensitization and. asthma due to fish processing as well as the exposure to airborne allergens. •Greater understanding of immunochemical properties of these agents and factors predisposing to the sensitization of exposed subjects.

References

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