Occupational allergies, mainly Asthma and Dermatosis, are one of the most frequent occupational diseases, with an estimated 10,000 new cases occurring each year, of which many remain undiagnosed. Allergic respiratory and skin diseases caused by agents and substances present in the workplace are included in the list of Occupational Diseases of the Social Security and are currently a major cause of incapacity for work.
What is occupational allergy?
An allergy is a reaction that occurs as a consequence of an abnormal or inadequate response of the immune system to a sensitizing substance or agent called an allergen. When the sensitizing agent or allergen comes from the work environment, we speak of occupational allergy, in which there is a demonstrable cause-effect relationship between the substance present in the work environment and the allergic symptomatology.
How does it manifest itself?
The clinical manifestations of occupational allergies can be divided into two main groups, respiratory diseases and skin diseases, with a third group that would be assigned to the most severe form of manifestation of allergic diseases, anaphylaxis.
Respiratory allergic diseases
Respiratory allergic diseases caused by the inhalation of substances and agents present in the workplace are the most prevalent group in countries with a high level of development and, according to published data, represent the fourth cause of absenteeism from work in Spain. The most frequent forms of allergic respiratory disease are rhinitis and asthma, and both can be of occupational origin (the disease debuts in the workplace) or preexisting to a specific work activity that exacerbates the pathology (work-exacerbated disease).
Work-related asthma is currently the most frequent respiratory disease of occupational origin in developed countries, and it is estimated that it can cause up to 25% of all cases of asthma in adulthood. This asthma can be of allergic cause (immunological asthma) or of non-allergic cause (irritative asthma) and the allergens most frequently involved in the allergic form are substances of high molecular weight, with atopy as a risk factor (atopic dermatitis, allergy to pollens, etc.).
With respect to professions with a higher risk of occupational asthma have been described:
- Laboratory technicians.
- Painters (with spray paint, containing isocyanates).
- Bakers and food industry workers in general.
- Plastics and rubber industry workers.
- Welders.
- Employees in cleaning tasks.
In relation to rhinitis, it is important to know that it is common for the nasal symptoms of rhinitis to precede the onset of asthma symptoms by months or years, and in many cases rhinitis is considered to be the “prelude” to asthma. Several studies establish that rhinitis symptoms precede those of occupational asthma in between 20% and 78% of patients, especially in the case of high molecular weight allergens.
Other respiratory allergic diseases
Among the respiratory allergic diseases, we must also highlight the group formed by hypersensitivity pneumonitis or extrinsic allergic alveolitis, mainly due to the risk it entails for the worker’s health as it is a disease that can evolve into pulmonary fibrosis.
A multitude of agents responsible for triggering this condition are currently known and new agents are frequently added to the list as time goes by. The two best known entities within extrinsic allergic alveolitis are “poultry keeper’s lung” caused by proteins in poultry serum and droppings, and “farmer’s lung” caused by fungi present in moldy hay, where the concentration of exposure is an important risk factor in the development of the disease.
Hypersensitivity pneumonitis should be suspected in a worker with exposure to organic substances who develops a respiratory clinical picture with predominantly dry cough and dyspnea, and associated fever and malaise. The symptoms will subside when contact with the allergen ceases and will reappear if such contact occurs again, except in chronic forms of the disease that may not subside. It is important to note that chronic forms of hypersensitivity pneumonitis can be difficult to diagnose and are sometimes mistaken for COPD. The diagnosis will be confirmed with a thorough clinical history and specific findings in imaging (X-ray, CT) and laboratory tests (serology).
Cutaneous allergic diseases: occupational dermatoses
Occupational dermatoses represent 30% of work-related diseases, and include skin conditions caused, conditioned, promoted, maintained or aggravated as a consequence of work activity. Basically, occupational dermatosis is any skin disease caused by work and contact dermatitis is the most frequent form of expression.
It is estimated that 90-95% of occupational dermatoses correspond to contact dermatitis, of which 20-25% are allergic dermatitis and the rest are irritant. The clinical manifestations of a dermatitis will be different according to the phase of the disease:
- In its acute phase, erythema (redness) of the skin with intense itching and inflammation will appear, sometimes accompanied by vesicles and exudation of clear fluid.
- In its chronic phase the symptoms of dermatitis will consist of thickening of the skin, desquamation, edema, vesicles (sometimes even blisters), and painful fissures. With regard to localization, the hands are the most frequently affected organ (up to 80-90% of occupational dermatitis affects the hands), followed by the arms, face and neck, which can be affected by environmental exposure to dusts or vapors (airborne mechanism), and also by accidental transmission of allergens and/or irritants through contaminated hands and gloves.
Anaphylaxis
The European Academy of Allergology and Clinical Immunology (EAACI) defines Anaphylaxis as a severe and potentially fatal systemic hypersensitivity reaction characterized by a rapid onset of respiratory, circulatory or gastrointestinal problems, usually associated with skin and mucosal changes in the form of urticaria and angioedema.
Occupational anaphylaxis would be defined as anaphylaxis produced by agents or conditions attributable to a particular work environment, with an estimated incidence of the pathology between 0.1 and 2.4%. Anaphylaxis is the most severe expression of an allergic disease, can occur at any time and can very quickly compromise the patient’s life due to the development of anaphylactic shock caused by the massive release of inflammatory mediators after contact with the allergen to which the patient is sensitized.
The food industry is one of the occupational settings described as a cause of occupational anaphylaxis due to inhalation of allergens present in foods and additives. Cases of anaphylaxis have been described in workers handling foods of plant origin, foods of animal origin and food additives. Another important cause described in cases of occupational anaphylaxis is latex proteins.
What does the law say about occupational allergies?
From a medical point of view, the main problem when a worker develops an allergy to some agent or substance present in his workplace is that the symptoms of the allergic disease will appear whenever he is exposed to the substance, even at very low concentrations. Applying legal concepts to this premise of occupational allergy, an allergen must always be understood as a toxic agent for the individual who is sensitized, and therefore the concept of occupational allergy must be linked to the concept of occupational injury, defined in article 4 of Law 31/1995, of November 8, 1995, on Occupational Risk Prevention (LPRL), as that derived from work, and which includes diseases, pathologies or injuries suffered as a result of or on the occasion of work.
Allergic respiratory and skin diseases at work will be classified as occupational diseases as established by Royal Decree 1299/2006 of November 10, 2006, when the substances or the immunological sensitizing mechanism fall into one of these groups:
- Group 1: occupational diseases caused by chemical agents.
- Group 4: occupational diseases caused by inhalation of substances and agents not covered elsewhere.
- Group 5: occupational diseases of the skin caused by substances and agents not covered elsewhere.
An individual suffering from any of the occupational diseases caused by agents included in these groups must be diagnosed as an occupational disease of allergic origin and must always be removed from the workplace in which the substance is present.
Occupational allergies are a serious public health problem both because of the consequences for the quality of life of those affected and because of the economic repercussions for society due to the loss of productivity of sick workers and the expenses derived from their health care and economic benefits for situations of incapacity, which in many cases will be permanent. This, added to the progressive increase in the prevalence of allergic diseases in multiple work environments, makes the application of a Specific Occupational Health Protocol for the Prevention of Occupational Allergic Diseases increasingly necessary.
In addition to improving worker protection, the application of a Specific Occupational Health Protocol for allergic diseases will protect against possible liability claims for inadequate health surveillance of workers, by complying with Article 22 of Law 31/1995 of November 8, 1995 on Occupational Risk Prevention (LPRL), which states that to ensure that health surveillance is effective and is carried out with maximum guarantees for the worker, one of the characteristics it must meet is to be Specific.