Date Published: February 28, 2017
Publisher: Springer Medizin
Author(s): Gerhard A. Wiesmüller, Birger Heinzow, Ute Aurbach, Karl-Christian Bergmann, Albrecht Bufe, Walter Buzina, Oliver A. Cornely, Steffen Engelhart, Guido Fischer, Thomas Gabrio, Werner Heinz, Caroline E. W. Herr, Jörg Kleine-Tebbe, Ludger Klimek, Martin Köberle, Herbert Lichtnecker, Thomas Lob-Corzilius, Rolf Merget, Norbert Mülleneisen, Dennis Nowak, Uta Rabe, Monika Raulf, Hans Peter Seidl, Jens-Oliver Steiß, Regine Szewszyk, Peter Thomas, Kerttu Valtanen, Julia Hurraß.
This article is an abridged version of the AWMF mould guideline “Medical clinical diagnostics of indoor mould exposure” presented in April 2016 by the German Society of Hygiene, Environmental Medicine and Preventive Medicine (Gesellschaft für Hygiene, Umweltmedizin und Präventivmedizin, GHUP), in collaboration with the above-mentioned scientific medical societies, German and Austrian societies, medical associations and experts. Indoor mould growth is a potential health risk, even if a quantitative and/or causal relationship between the occurrence of individual mould species and health problems has yet to be established. Apart from allergic bronchopulmonary aspergillosis (ABPA) and mould-caused mycoses, only sufficient evidence for an association between moisture/mould damage and the following health effects has been established: allergic respiratory disease, asthma (manifestation, progression and exacerbation), allergic rhinitis, hypersensitivity pneumonitis (extrinsic allergic alveolitis), and increased likelihood of respiratory infections/bronchitis. In this context the sensitizing potential of moulds is obviously low compared to other environmental allergens. Recent studies show a comparatively low sensitizing prevalence of 3–10% in the general population across Europe. Limited or suspected evidence for an association exist with respect to mucous membrane irritation and atopic eczema (manifestation, progression and exacerbation). Inadequate or insufficient evidence for an association exist for chronic obstructive pulmonary disease, acute idiopathic pulmonary hemorrhage in children, rheumatism/arthritis, sarcoidosis and cancer. The risk of infection posed by moulds regularly occurring indoors is low for healthy persons; most species are in risk group 1 and a few in risk group 2 (Aspergillus fumigatus, A. flavus) of the German Biological Agents Act (Biostoffverordnung). Only moulds that are potentially able to form toxins can be triggers of toxic reactions. Whether or not toxin formation occurs in individual cases is determined by environmental and growth conditions, above all the substrate. In the case of indoor moisture/mould damage, everyone can be affected by odour effects and/or mood disorders. However, this is not a health hazard. Predisposing factors for odour effects can include genetic and hormonal influences, imprinting, context and adaptation effects. Predisposing factors for mood disorders may include environmental concerns, anxiety, condition, and attribution, as well as various diseases. Risk groups to be protected particularly with regard to an infection risk are persons on immunosuppression according to the classification of the German Commission for Hospital Hygiene and Infection Prevention (Kommission für Krankenhaushygiene und Infektionsprävention, KRINKO) at the Robert Koch- Institute (RKI) and persons with cystic fibrosis (mucoviscidosis); with regard to an allergic risk, persons with cystic fibrosis (mucoviscidosis) and patients with bronchial asthma should be protected.
In April 2016, the German Society of Hygiene, Environmental Medicine and Preventive Medicine (Gesellschaft für Hygiene, Umweltmedizin und Präventivmedizin, GHUP), in collaboration with the above-mentioned scientific medical societies, German and Austrian societies, medical associations and experts, presented the AWMF mould guideline “Medical clinical diagnostics of indoor mould exposure” .
The problem of indoor mould exposure needs to be addressed in a more fact-based manner.Relevant levels of indoor mould infestation must not be tolerated for precautionary reasons. For the assessment of damage extent, the reader is referred to the “Guideline on the prevention, investigation, evaluation and remediation of indoor mould growth” (mould guideline) issued by the German Federal Environment Agency (Umweltbundesamt, UBA) . A revised version of the UBA mould guideline is expected in 2017.The most important measures in indoor mould exposure include cause identification and appropriate remediation (see mould remediation guides [3, 5]).Medically indicated indoor mould measurements are rarely helpful. In general, both quantitative and qualitative determinations of the mould species can be dispensed with in the case of visible mould infestation. Instead, identifying the cause of infestation is far more important, followed by the elimination of infestation and its primary causes.Mould exposure can generally lead to mucous membrane irritation (MMI), odour effects and mood disorders.Specific clinical pictures seen in mould exposure are pertinent to allergies and fungal infections (mycosis).It is the physician’s duty to objectify suspected links between indoor moisture damage/mould and gastrointestinal or renal disease, reproductive disorders, teratogenicity or cancer.Risk groups warranting particular protection include:individuals on immunosuppression according to the classification of the German Commission for Hospital Hygiene and Infection Prevention (Kommission für Krankenhaushygiene und Infektionsprävention, KRINKO) at the Robert Koch-Institute (RKI) ,individuals with cystic fibrosis (mucoviscidosis),individuals with bronchial asthma.The risk for developing asthma (“allergic march”) is increased in:patients with allergic rhinoconjunctivitis,patients with allergic rhinosinusitis,atopic patients.It is likely that all moulds are capable of causing sensitization and allergies. Their allergenic potential is considered lower compared with other environmental allergens [12, 13].As polysensitized individuals, atopics (those susceptible to hypersensitivity reactions, such as allergic rhinitis (hay fever), allergic asthma, and atopic dermatitis on contact with environmental substances) often also exhibit IgE antibodies to moulds; however, this does not necessarily indicate relevant disease.The core elements of allergy diagnostics include medical history, skin testing (skin prick test), in vitro serological examination of specific IgE antibodies in type I sensitization or specific IgG antibodies in hypersensitivity pneumonitis (HP; extremely rare in non-occupationally related indoor exposure) and provocation testing.The identification of specific IgE means that a specific sensitization to relevant allergens is present. However, this cannot be equated to a clinically relevant allergy any more than a positive skin test reaction can be.Negative in vitro and in vivo tests do not exclude sensitization or mould allergy.The determination of specific IgG antibodies as part of the diagnostic work-up for immediate-type mould allergy (type I allergy) is of no diagnostic relevance and is therefore not recommended.Lymphocyte transformation testing (LTT) for moulds is not indicated as a diagnostic method .Mould-related infections are rare and are most likely to occur via the inhalative route. In practice, Aspergillus fumigatus—the most important mycotic pathogen—is of the greatest relevance among the 460 moulds classified in risk groups 2 and 3 according the German Technical Rules for Biological Materials (Technische Regeln für Biologische Arbeitsstoffe, TRBA). Individuals with local or general immunodeficiency are by far those most frequently affected.Core elements of the diagnostic work-up for mould infection include microbiological, immunological, molecular biological and radiological methods.Mould-allergic individuals, as well as patients with diseases that weaken the immune system, should be provided with specialist patient information on the hazards of indoor mould exposure and the preventive steps that can be taken to minimize this exposure.
The guideline is intended to close the existing gap in the rational and efficient medical diagnostics of indoor mould exposure. To date, only guidelines on building-related procedures in the case of moisture damage [2–6] and overview articles on associated diseases [7–10] have been available—however, no comprehensive, patient-related diagnostic procedure.
A national network of experts belonging to the German Society for Hygiene, Environmental Medicine and Preventive Medicine (Gesellschaft für Hygiene, Umweltmedizin und Präventivmedizin, GHUP) was used to compile the AWMF mould guideline. The guideline builds on the statements of the Robert Koch-Institute (RKI) Commission ‘Methods and Quality Assurance in Environmental Medicine’ (Kommission Methoden und Qualitätssicherung in der Umweltmedizin) , the World Health Organization (WHO) Guidelines for Indoor Air Quality: Dampness and Mould  and the scientific workshops held at the GHUP annual conferences (GHUP 2009–2012) on the subject of “mould and health” [15–18].
Even if no causal link can be established between symptoms/findings/disorders and the occurrence of indoor mould/dampness, the first “therapeutic” measure to be undertaken from a preventive and hygienic perspective in the case of dampness/mould damage is prompt appropriate and professional remediation; moreover, in the case of severe clinical pictures associated with high risk (immune suppression according to KRINKO criteria , cystic fibrosis [mucoviscidosis], asthma), immediate minimization of exposure needs to be achieved.
Proper remediation of dampness/mould damage includes the elimination of structural cause(s), the drying out and removal of all mould-infested materials as well as subsequent fine cleaning. Details of these procedures do not form part of this guideline. More detailed information can be found in the relevant mould guidelines [2, 3, 5], as well as the revised version of the UBA guideline (due to be published 2017).
Statistical surveys show that dampness/mould damage is more frequently reported in homes of individuals with low social status compared with the general population (e. g. German Federal Statistical Office, 2006). This gives rise to particular problems for low-social-status individuals in terms of the likelihood of dampness/mould damage and its remediation .
It is important, as a first step, to provide susceptible and immunosuppressed patients with information on the risks associated with indoor mould exposure and preventive measures [238, 239], possibly supplemented by home visits to inspect for Aspergillus fumigatus and Aspergillus flavus (only rarely found indoors) .