Toxic Molds: Revisited (2007)

Indoor Toxic Molds and their Symptoms

By Nachman Brautbar, M.D.


In the outdoor environment molds are ubiquitous. Moist conditions involving drywall, wood, carpeting, or paper material are the proliferation medium in the indoor environment for toxic molds. Since Americans spend 75 to 90% of their time indoors, the risk of exposure to toxic molds that may grow indoors is increased. [1] Toxic molds enter the indoor environment through doorways, windows, heating and ventilation systems, and air conditioning systems, given the appropriate circumstances. Spores from toxic molds in the air deposit on people, animals, clothing, shoes, and bags, turning them into common and potential carriers of toxic molds into the indoor environments (home and office). [2] Indoor environments that contain excessive moisture such as leakage from roofs, walls, plant pots, or pet urine cause proliferation and development of molds. The most common molds which are found indoor are Cladosporium, Penicillium, and Aspergillus. In order to proliferate, molds need nutrients which are commonly present in building environments such as cellular substrates in paper, paper products, cardboard, ceiling tiles, wood, wood products, drywall, carpet, fabric, insulation materials, wallpaper, paints, and dusts.

Depending on the quantities produced and consumed, mycotoxins can cause acute or chronic toxicity in animals and humans. Home dampness with resulting mold growth may be associated with several medical conditions (one or sometimes all) including immediate hypersensitivity reaction, hypersensitivity pneumonia, or what has been described as "humidifier fever". I see these patients with recent onset asthma, and/or recent onset sinusitis. [3],[4] Several studies have suggested a correlation between the occurrence of molds in the inside air environment, dampness in the indoor environment, and the symptomatology of the skin, and respiratory tract, especially in children. This has been summarized in an interesting study published in the American Journal of Epidemiology by Robert E. Dales. [5] Since the symptoms in this study were comparable to the symptoms described with humidifier fever and mycotoxicosis, the authors suggested a common pathogenic and etiological mechanism, toxic molds being one. [5],[6]

The role of indoor molds, especially the most toxic one - Stachybotrys, has been evaluated in a scientific paper published in the journal Pediatrics. [7] The authors described a child with pulmonary hemorrhaging where Stachybotrys was isolated from the lung. Indeed, epidemiological data to support the connection between toxic mold exposure and lung hemorrhage was published in the scientific literature from Cleveland, Ohio, which was later examined and criticized by the Center for Disease Control. [8],[9] The study by Elidemir et al. shows the isolation of the toxic mold Stachybotrys atra from the BAL fluid of a child with pulmonary hemorrhage, thus connecting the epidemiological data and the historical data in this case report with objective findings of Stachybotrys from lung fluids. In the scientific paper entitled "Stachybotrys: Mycotoxin Producing Fungus of Increasing Toxicological Importance" the investigators concluded "Current data on the toxicology of mycotoxins produced by Stachybotrys demonstrates that this group of mycotoxins is capable of producing immunosuppression and inflammatory insults to the gastrointestinal and pulmonary system". [10] Bush et al. provides a diametrically opposed consensus, as far as indoor mold exposure and clinical human disease. [11] On the other hand, recent communication with the President of the American College of Occupational and Environmental Medicine (ACOEM) has criticized some of the statements in the recent position paper by ACOEM in regards to molds. [12] The major criticism by the author of the e-mail communication is that there is no scientific paper which can address safe or minimal exposure levels to molds. [13] The criticism also quotes writings from the Wall Street Journal questioning the ACOEM paper on molds [not the organization and not the ACOEM President; the organization is well-respected (I am a member), and the ACOEM President is highly qualified and nationally, internationally recognized as a scientist, writer, professor, and teacher]. [14] It seems the criticism was launched at one author or so of the position paper by ACOEM. To be balanced and fair, while the honorable court decision in the Geffcken case [15] is important, the honorable court decision in the Harold case [16] must be taken into account. One must also rely on the Institute of Medicine's position paper [17] and the rest of the scientific literature in the final analysis of causation.

What to do when you suspect toxic molds as a cause for symptomatology. First and most importantly is to see a doctor who specializes in the fields of internal medicine, occupational medicine and toxicology. Upon determination that these symptoms may be related to mold exposure, you should have an industrial hygienists inspect your residence or alternatively office/work place (depending on where the suspected mold resides) to do a careful investigation of any water damages, and air counts both inside and outside at several locations for toxic molds and spores A well-trained industrial hygienist will not only take air counts but also will go under and behind the walls and/or carpeting where the water damage is anticipated to be in order to further evaluate for mold spores and mold growth.

During the last 8 years I have treated patients with various mold related illnesses contracted at either industrial buildings such as old buildings, schools, and governmental offices, as well as residences, all of which have suffered either faulty ventilation, water damages, or both. The most common presenting symptoms are those of transient 1) cough, 2) asthma, atypical asthma, 3) nasal congestion, 4) sinusitis/rhinitis, 5) skin rashes, and 6) generalized fatigue. Based on the current available literature, symptomology is transient and improves upon removal from the exposure source or remediation. The overall consensus based on the totality of scientific data, clinical experiences and methodological causation analysis will guide the clinician in ruling in or out causation. [14],[15],[16],[18],[19],[20],[21] For causation determination, the doctor should use the methodology commonly used in diagnosing and treating the condition, and utilize, among others, careful review of other causes, temporal relationship and whether there is biological plausibility that mold have been shown in humans to cause these types of symptoms or diseases.

Immunological Studies

Much controversies center around these studies. Recently, it was concluded that the immunologic studies of "mycotoxins" are not reliable, nor can they be used for ruling in or out mold exposure. [11] The same line was followed by a recent court decision. [15] The current consensus based on most recent scientific data is that immunologic studies as a marker of mold exposure are not helpful; at best IgE antibody may suggest that one was exposed to mold some time in life, but relevancy to causation assessment in mold exposure cases is questionable.


[1]Leibowitz MD, Health effects of indoor pollutants, Annual Review of Public Health, I983, Volume 4, 203-211.

[2]Miller JD, Fungi as contaminants in indoor air, Atmospheric Environment, 1992, Volume 26, 2163-2172.

[3]Edward JH, et al, Humidifier fever, Thorax, 1977, Volume 32, 653-663.

[4]Arundel AV, et al, Indirect health effects of relative humidity in indoor environment, Environmental Health Perspective, 1986, Volume 65, 351-361.

[5]Dales RE, Respiratory health effects of home dampness and molds among Canadian children, American Journal of Epidemiology, 1991, Volume 134, Number 2,196-203.

[6]May JJ, et al, Organic dust toxicity, pulmonary mycotoxicosis associated with silo unloading, Thorax, 1986, Volume 41, 919-923.

[7]Fung F, et al, Stachybotrys, a mycotoxin-producing fungus of increasing toxicologic importance, Journal of Toxicology. Clinical Toxicology, 1998, Volume 36, 79-86.

[8]Montana E, et al, Environmental risk factors associated with pediatric idiopathic pulmonary hemorrhage and hemosiderosis in a Cleveland community, Pediatrics, 1997, Volume 99, Number 1, E5.

[9]Atzel RA, et al, Acute pulmonary hemorrhage in infants associated with exposure to Stachybotrys Atra and other fungi, Archives of Pediatrics and Adolescent Medicine, 1998, Volume 152, 757-762.

[10]Elidemir O et al, Isolation of Stachybotrys from the lung of a child with pulmonary hemosiderosis, Pediatrics, 1999, Volume 104, 964-966.

[11]Bush RK, et al, The medical effects of mold exposure, Journal of Allergy and Clinical Immunology, 2006, Volume 117, Number 2, 326-333.

[12]Hardin BD, et al. Adverse human health effects associated with molds in the indoor environment. ACOEM evidence-based statement, Journal of Occupupational and Environmental Medicine, 2003, Volume 45, 470-478.

[13]Communication between ACOEM and Sharon Kramer. Posted by Sharon Kramer on January 24, 2007. Available at:

[14]Armstrong D, Amid suits over mold, experts wear two hats. Authors of science paper often cited by defense also help in litigation, Wall Street Journal, January 9, 2007, A1.

[15]Eva Geffcken, et al. v. Samuel D'Andrea, et al. Court of Appeal of California, Second Appellate District Division Six. 137 Cal. App. 4th 1298, February 27, 2006, Filed.

[16]James Harold, et al. v. California Casualty Insurance Company, et al. Superior Court of the State of California for the County of Sacramento, Case No. 02AS04291, April 2006.

[17]Institute of Medicine, Damp indoor spaces and health, Committee on Damp Indoor Spaces and Health, Board on Health Promotion and Disease Prevention, The National Academy of Sciences, 2004. ISBN: 0-309-09193-4.

[18]Brautbar N, Science and the law: scientific evidence, causation, admissibility, reliability - "Daubert" decision revisited, Toxicology and Industrial Health, 1999, Volume 15, 532-551.

[19]Brautbar N, Scientific evidence, Chapter 15, pages 92- 121, In: Ethics in Forensic Science and Medicine, MA Schiffman (ed), Charles C. Thomas Publisher, Ltd, 2000.

[20]Gravesen S, Fungi as a cause for allergic disease, review article, Allergy, 1979, Volume 34, 135-154.

[21]Hodgson, Building-associated pulmonary disease from exposure to Stachybotrys Chartarum and Aspergillus Versicolor, Journal of Occupational and Environmental Medicine, 1998, Volume 14, Number 3, 241-249.

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