Quality of Life and Capsaicin Sensitivity in Patients with Airway Symptoms Induced by Chemicals and Scents: A Longitudinal Study
Ternesten-Hasseus, Ewa, Lowhagen, Olle, Millqvist, Eva, Environmental Health Perspectives
OBJECTIVE: It is common in asthma and allergy clinics to see patients presenting with upper and lower airway symptoms that are induced by chemicals and scents and not explained by allergic or asthmatic reactions. Previous studies have shown that these patients often have increased cough sensitivity to inhaled capsaicin; such sensitivity is known to reflect the airway sensory reactivity. The aim of this study was to evaluate the duration of symptoms induced by chemicals and scents and to measure health-related quality of life (HRQL) in patients with chemically induced airway symptoms. We also wished to determine and compare repeatability of the cough response to capsaicin inhalation, and to evaluate the patients' airway sensory reactivity in a long-term perspective.
PARTICIPANTS: Seventeen patients with a history of at least 12 months of airway symptoms induced by chemicals and scents were followed over 5 years with repeated questionnaires, measurements of HRQL, and capsaicin inhalation tests.
RESULTS: The symptoms persisted and did not change significantly over time, and the patients had a reduced HRQL that did not change during the 5-year period. The capsaicin sensitivity was increased at the start of the study, the cough sensitivity was long-lasting, and the repeatability of the capsaicin inhalation test was considered to be good in a long-term perspective.
CONCLUSIONS: Upper and lower airway symptoms induced by chemicals and scents represent an entity of chronic diseases, different from asthma or chronic obstructive pulmonary disease, with persistent symptoms, a reduced HRQL, and unchanged sensory hyperreactivity.
KEY WORDS: asthma, capsaicin, cough, environment, health-related quality of life, multiple chemical sensitivity, sensory hyperreactivity. Environ Health Perspect 115:425-429 (2007). doi:10.1289/ehp.9624 available via http://dx.doi.org/ [Online 19 December 2006]
Previous studies have described patients with upper and lower airway symptoms induced by chemicals and scents (Johansson et al. 2006; Millqvist 2000; Millqvist et al. 1998; Ternesten-Hasseus et al. 2002a, 2002b). Inducing factors can include perfume, flowers, cleaning agents, car-exhaust fumes, and cigarette smoke. Steroids, [[beta].sub.2]-agonists, and other pharmacologic treatment for asthma or allergy have weak effects or none at all. Common symptoms are heavy breathing, difficulty getting air, cough, hoarseness, phlegm, nasal blockage, rhinorrhea, and eye irritation. The symptoms are often misinterpreted as asthma and/or allergy. Sensory hyperreactivity (SHR) is one suggested explanation for these airway symptoms induced by chemicals and scents (Johansson et al. 2002; Millqvist et al. 1998). The diagnostic criteria for the proposed diagnosis of SHR include self-reported sensitivity to chemicals and scents and a positive reaction to a capsaicin inhalation test, with the cut-off values described by Johansson et al. (2002). The prevalence of SHR has been estimated at 6.3% (Johansson et al. 2006).
There is a strong resemblance between SHR and multiple chemical sensitivity (MCS), but the diagnosis of SHR implies that just one organ is affected--the airways--whereas in MCS, symptoms from multiple organs are involved. However, some patients with SHR also complain of more general symptoms, such as sweating, dizziness, headache, and fatigue, bordering on a diagnosis of MCS (Ternesten-Hasseus et al. 2002a). MCS is also known as "the 20th century disease," "chemically acquired immunodeficiency syndrome," "total allergy syndrome," and "idiopathic environmental intolerances" (American Academy of Allergy, Asthma and Immunology Board of Directors 1999; Graveling et al. 1999). MCS is associated with a generalized sensitivity to low doses of chemicals (normally regarded as nontoxic) in the environment, with symptoms from various organs (including the airways) and often nonspecific symptoms such as fatigue and cognitive difficulties. …