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SICK BUILDING SYNDROME

by Dr Nerys Williams MB ChB, MRCGP, FFOM, Consultant Occupational Physician, Solihull

In sick building syndrome (SBS), individuals experience a range of symptoms when they are in specific buildings. It has been recognised by the World Health Organisation (WHO) since 1982, but was described by Black as long ago as 1960. There are different definitions of the syndrome in different countries, but they all define it in terms of its presentation rather than its cause. Studies and reviews have failed to find a single proven cause and the condition remains difficult both to diagnose and to manage. It is a complex phenomenon with physical and psychosocial factors in its aetiology.

Sick building syndrome is common. It has been estimated that 30-50% of new or refurbished buildings with recirculating ventilation or air conditioning have symptomatic workers and up to 85% of people working in specific buildings may be affected. Apart from effects on productivity and morale, SBS has been shown to increase absenteeism and unofficial time off, reduce overtime availability and increase staff turnover. It therefore presents a problem for both workers and employers.

GPs can also find SBS in their own staff where the consequences can be just as disruptive as in industry. Buildings have been closed whilst investigations are carried out.

Symptoms of SBS

The symptoms of SBS include tiredness, headaches, fatigue, dry ears and skin, sore throats, hoarseness and wheezing, itching and an increased frequency of respiratory infections (Box 1). They tend to occur in certain buildings, increase as the day progresses and improve when the affected patient(s) leaves the building. A sufferer may give a history of symptoms during the daytime, with symptom-free periods in the evenings, at weekends and during holidays. Shift workers may have symptoms outside usual working hours. The severity of symptoms varies, and the complaints are often so mild that GPs are not consulted. Although there is no evidence of any long-term deleterious effect on health, studies have shown that even mild symptoms affect individual performance and productivity, and may lead to disciplinary action for poor performance and personal stress.

It is important to exclude medical conditions which have similar symptoms to SBS, such as vasomotor or allergic rhinitis. When SBS is suspected, it is useful to question the patient about general workplace conditions as SBS occurs more frequently if certain features are present (Box 2).

Other contributory environmental factors include:

inadequate ventilation;
high uniform temperature and lack of air movement;
poor lighting, particularly little daylight;
airborne organic matter from the air-conditioning system;
airborne chemical pollution, and
low morale and general dissatisfaction with work and/or the environment.

Airborne chemical pollution

Airborne chemical pollution may originate in the building itself, in the furnishings or in equipment. It can be caused by:

Ozone. This gas is emitted from photocopiers and laser printers which are inadequately serviced. The characteristic 'fresh' smell of the gas is not found if in-built filters are regularly checked and maintained.
Volatile organic compounds. These are emitted by paints and cleaning agents.
Dusts. Human skin, paper and photocopy toners can all generate dust.
Formaldehyde. This is emitted from fabrics, carpets and insulation materials.
Organic (house dust mite) and inorganic (eg tobacco smoke) materials must also be considered if symptoms are to be minimised.

Differential diagnosis

It is important to exclude other building-related conditions (Box 3) before concluding that SBS is the cause of a patient's symptoms.

Air conditioner lung diseases

Two distinct syndromes of air conditioner lung disease have been described.

Humidifier fever

This is not notifiable, so the true prevalence of humidifier fever is unknown. Outbreaks are rare and occur when there is excessive microbiological growth in the sludge of spray humidifiers. As recirculated water enters the air of the workplace, workers (and it is usually more than one) begin to complain of symptoms ranging from mild influenza to an acute illness with fever, headache, myalgia and breathlessness.

Symptoms usually resolve within 24 hours and are distinguished from extrinsic allergic alveolitis by their periodicity. In humidifier fever, the symptoms are usually most severe on the first working day, improve towards the end of the week and then reappear when the person returns to work after an absence.

Between 2.5 and 40% of individuals will be affected in an outbreak1 and there are unlikely to be any X-ray changes. The diagnosis is made from the history, peak flow records over several weeks and by measuring serum precipitins. Provocation testing, using a sample from a suspected humidifier, can also be undertaken.

Future ill health can be prevented by improved management of air conditioning units. GPs should consider humidifier fever, and the need for workplace action, in any patient who has recurrent episodes of a febrile illness, a normal chest X-ray and symptoms which are worse at the beginning of the working week. It is important to ask whether the patient has any colleagues with a similar problem.

Extrinsic allergic alveolitis (EAA)

The symptoms, physical signs, lung function and radiology are identical to EAA due to other causes. Patients with chronic disease have a gradual onset of breathlessness on exertion.

There have only been two published reports of workplace outbreaks(2,3), so more common causes of EAA should be considered first. It can be caused by a number of agents, including thermophilic actinomycetes.

The diagnosis is made from the history, peak flow readings (which show gradually reducing air flow as the week progresses), radiological changes, measurement of serum precipitins and, if there is doubt, provocation testing. Unlike in humidifier fever, which patients usually recover from, EAA may result in a persisting disability.

Legionellosis

This term covers a group of conditions which includes legionnaire's disease (pneumonia) and the milder, and less common, Pontiac fever (which is caused by the same bacterium). About 200 cases are reported annually in England and Wales (PHLS unpublished data), most of which are sporadic and community-acquired.

There are also occasional outbreaks related to identifiable sources, such as evaporative cooling towers, spray humidifiers, spa baths and whirlpools. Legionella bacteria are widespread in the environment(4) and require moisture and warmth (25-42°C) for survival and growth. Legionnaire's disease is a severe condition, with 12% mortality and significant morbidity. Survivors often recover slowly with prolonged fatigue and poor memory.(5) The pneumonia has an incubation period of 2-10 days. However, only about 1% of people exposed to legionella actually develop symptoms, which include fever, cough, chills, muscle pains and breathlessness. Susceptible individuals include the elderly, smokers and those with chronic chest disease.

The diagnosis of legionellosis is made from the history, chest X-ray, and culture of the organism or a positive antigen test. It is treated using antibiotics and supportive therapy. Erythromycin is the antibiotic of choice, with rifampicin being added in severe cases.

Role of the GP

When faced with possible SBS, it is important to exclude other building-related illnesses. The diagnosis can be made easier by asking the patient to keep a symptom diary, documenting any symptoms and their relationship to work. If the diary confirms the diagnosis, the GP can then explain the condition and reassure the patient that SBS does not cause long-term health problems.

As the core of the problem rests in the work place, GPs are limited in how they can intervene. Patients should be asked for permission to inform their employer. Ideally GPs should liaise with the occupational health physician; if there is not one available, an occupational health nurse or trade union safety representative may be acceptable first contacts, before speaking or writing to company management (a step that some employees would be reluctant for you to take).

When contacting the company, it may be worth referring to the Health and Safety Executive published guidelines on SBS (see Further Reading).

If employers refuse to take action, employees have the option of consulting the health and safety regulators - either the Environmental Health Officers at the local council, for most offices, or inspectors of the Health and Safety Executive.

Sick notes

GPs should base their decision on whether to write a sick note for a patient with SBS on the clinical symptoms and the strength of their diagnosis. Signing a person off sick will not change the building environment, which is usually the problem. It is better to exclude other pathology, explain the condition thoroughly and offer help in liaising with the company.

SBS in the surgery

The following are among the points that should be considered if SBS is suspected within the surgery:

Could a local flu or URTI outbreak be the cause?
Is the problem local to one part of the building, or throughout it?
Are the heating and ventilation systems working correctly (particularly the humidity of the air and the number of air exchanges)?
Is the system being cleaned adequately, so that dust is not transported through the system?
What are the employees' views? Investigate their complaints - this may identify factors, such as ambient tobacco smoke or excessive temperature, which are causing or aggravating symptoms.

Conclusion

Sick building syndrome can be complicated to manage, either for GPs (Box 4) or for employers.

However, the simple steps outlined by this article should enable you to approach the problem in a consistent and targeted way and avoid devoting valuable resources unproductively.

Box 1. Symptoms associated with sick building syndrome

Eyes
- irritated, itching, dry
Nose
- irritated, runny, dry, blocked
Throat
- irritated, dry, sore
Head
- headache, lethargy, fatigue, difficulty in concentrating
Skin
- dry, rashes, irritating, itching.

Box 2. Characteristics of SBS

The work.
- SBS sufferers usually have sedentary jobs
- and are often intensive computer users.
Buildings
- problem buildings tend to date from the 1960s and 1970s
- more modern buildings can be affected
- while the condition is usually reported in offices, cases have also occurred in hospitals and factories
Environment
- workers have little control of their immediate workplace environment
- the ventilation system is usually centrally managed and cannot be adjusted in individual offices
- there may be no windows, or a lack of them
- levels of airflow and humidification may have been designed to suit the computers and equipment, rather than the workers
- it is not always appreciated how much heat several computers can generate, and how this can dry air, lower its humidity and lead to dry eyes (particularly uncomfortable for contact lens wearers) and facial dermatitis

Box 3. Other building-related illnesses

Air conditioner lung diseases
- humidifier fever
- extrinsic allergic alveolitis
Legionellosis

Box 4. Potential pitfalls

Taking total ownership of the problem and of its solutions
Not excluding other building-related illnesses
Liaison with the company or its advisers without the written permission of the patient

Practical points

Sick building syndrome is where individuals experience a range of symptoms when they are in specific buildings.
Thirty to fifty percent of new or refurbished buildings with recirculating ventilation or air conditioning are believed to have symptomatic workers.
It is essential to exclude medical conditions, such as allergic rhinitis.
Contributory factors include inadequate ventilation, high uniform temperature, lack of air movement, poor lighting, airborne organic matter, airborne chemical pollution and low morale.
Before concluding that SBS is the cause of the patient's symptoms, it is important to exclude other building-related conditions, such as air conditioner lung disease and legionellosis.
The patient should be asked to keep a symptom diary to allow any patterns to be established.
Permission should be sought to communicate the diagnosis to the company. GPs should ideally liaise with their local occupational health department.

References

1. Edwards JH, Griffiths AJ, Mullins J. Protozoa as sources of antigen in humidifier fever. Nature 1976; 264: 438-9.
2. Robertson AS, Burge PS, Wielnad GA, Carmalt MHB. Extrinsic allergic alveolitis caused by a cold water humidifier. Thorax 1987; 42: 32-7.
3. Fergusson RJ, Milne LJR, Crompton GK. Penicillium allergic alveolitis: faulty installation of central heating. Thorax 1984; 39: 294-8.
4. Fliermans CB, Cherry WB, Orrison LH, Thacker L. Isolation of Legionella pneumophilia from non-epidemic related aquatic habitats. Appl Environ Microbiol 1979; 37: 1239-42.
5. Nordstrom K, Kallings I, Dahnsjo H, Clemens F. An outbreak of legionnaire's disease in Sweden: report of sixty eight cases. Scand J Infect Dis 1983; 15: 43-55.