Allergens: How to Identify Common Indoor Allergens and Mold by Visual Inspection, Photos and Description InspectAPedia® -
Photo guide to common allergens in buildings
Photographs and comments about cat dander, dog dander, and dust mites in buildings
Photo guide to cockroach infestation in buildings
Photos and comments about fleas, bedbugs, mold, and pollen in buildings
This article uses photographs to illustrate and help identify various indoor allergens like mold, cat allergens, dog allergens, mouse or rodent allergens, dust mites, cockroach
and other insect fragments, mite fecals, and other help in identification of indoor
allergens such as cockroaches, dust mites, fleas, house dust, mold, mildew, pet
dander, pollen.
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers nor with topics or services discussed at this website.
Photographs of Indoor Allergens and Allergenic Particles
Cat Dander and Cat Hair in buildings
Cat dander (the black kitten Pippin at above left) is for many people a more serious allergen (and asthma aggravator) than dog dander (the dog katie, above left). Our page top photo shows insect jaws collected during a survey for dust containing cockroach parts and allergens.
Cat dander is widespread and we even find it present, usually at lower levels, in offices and homes where no cats reside. Animal dander may be brought in by dust and clothing on visitors. Our second photo (above left) shows cat hair in the microscope.
Details about finding and removing animal dander in buildings are provided at CAT DANDER in buildings.
Dog Dander and Dog Hair in buildings
Animal allergen Photos is our article on inspecting and addressing allergens from cats, dogs, and many other animals.
Pets, Pet Hair and Pet Dander as well as dust mites associated with animal dander are very common allergens in buildings.
The wall stains in this photo were caused by pets, probably a large dog, indicating that further indoor screening for animal dander may be in order.
Details about finding and removing animal dander in buildings are provided at CAT DANDER in buildings.
Our photos above show dog dander (along with human skin cells) stained pink with acid fuchsin to aid visibility for the photograph). Our photo at right shows dog hair collected in an indoor dust sample, in this case the hair is further identified as from a golden retriever.
Testing people for exposure to allergens is a different activity from testing buildings for the presence of animal or other allergens. When human tests, such as the ELISA and RAST tests for exposure to allergens, indicate that someone has been exposed to problematic levels of animal allergens, there may still be confusion about just where the exposure is occurring. We discuss testing buildings for presence of allergenic particles such as dog dander, cat dander, insect or roach fragments, etc. at ALLERGEN TESTS for buildings.
ELISA and RAST tests for Allergen Exposure - The Basics
ELISA "enzyme-linked immunosorbent assay" is a rapid immunochemical test procedure that involves an enzyme (a protein that catalyzes a biochemical reaction) that tests for hormones, bacterial antigens, and antibodies. ELISA testing also involves an antibody or antigen (immunologic molecules).
RAST is an older allergen test (exposure detection) in popular use for testing humans, radioallergosorbent test, an IgE test: In this test, a sample of blood is taken, mixed with the suspected allergen, and the level of immunoglobulin E (IgE) is measured. IgE is an antibody produced by the immune system that indicates an allergic reaction.
The ELISA and RAST allergen exposure tests, their accuracy and their usefulness are discussed at ALLERGEN TESTS for buildings.
Cockroach Fecals, Fragments, Hairs as Indoor Allergens and Causes of Asthma
Cockroaches (also see photo at page top) - are the source one of the most common insect allergens found indoors in urban areas.
Cockroach fecal pellets, insect hairs, and insect fragments are often identified in house dust where roaches are present.
Our photo, left, shows cockroach carapace parts and hairs from an indoor dust sample.
Photos and Examples of Dust Mites and Dust Mite Fecals in buildings
Dust mites: our photo (left) shows a dust mite collected in an indoor surface dust sample.
We've stained the mite blue using lactophenol cotton blue to make its parts more attractive and easy to discern.
Dust mite fecal pellets: Our photo (left) shows a mix of dust mite fecal pellets and Penicillium/Aspergillus spores collected in a surface dust sample from a building. The dust mite fecal pellets can assist in a building investigation for allergens by telling us what the dust mite or other insect was eating - in this case mold spores.
Dust mite surrounded by other house dust particulate debris
Here is a mite found among pollen in the flower of a Tulip Poplar.
You won't see dust mites without a microscope, but if your home has any or all of dampness, wet areas, pets, lots of dust and organic debris, old mattresses and pillows, couches, carpets, heavy curtains,
or if you go to sleep with wet hair on your pillow, you're likely to have a high dust mite population.
Mites, mite parts, and mite fecals show up in indoor dust samples examined by microscope. Dust mites are
present wherever people and animals live. But high levels of mite fecals raises the level of allergens in the Building and may be a problem.
Fiberglass Insulation Mold comments about a field study in process, & more about health hazards from fiberglass insulation - DJF
Fleas and Bedbugs as serious building pests also may produce allergens.
Pollen Allergens in Building Air and Dust Samples
Pollen Photo Library a photo library of pollen & the flowers, shrubs, trees from which pollen was collected.
Mice and Rats in buildings as Allergen Sources
Mice hair, dander, and fecals are often observed during an indoor air quality or environmental inspection.
Our photo (left) shows mouse hair found in indoor dust during an environmental inspection and test.
We often find mouse droppings, hair, dander, and mouse remains in attics, basements, walls, ducts, and food-storage cabinets.
If mice and rats are a problem in a building, in addition to needing professional extermination services, you'll need to look at the housekeeping practices in the home and in neighboring apartments or homes, especially food storage.
Recognizing Mold: What mold looks like mold identification photos to help identify mold - choosing what to sample in buildings
Check With Your Doctor About Allergens and About Whether or Not Building Tests for Allergens or Mold are Recommended
Of course since individual sensitivity to allergens varies, we suggest that anyone suffering from allergies and considering steps to further clean their home should also consult with their allergist and their general physician.
Safety Warning: if indoor air quality complaints include respiratory distress, headaches, nausea, and similar symptoms, it is important to immediately rule out unsafe heating equipment, chimneys, flues, or carbon monoxide hazards. See CARBON MONOXIDE - CO
The types, accuracy, and variability of human tests for allergy sensitivity and allergy or mold exposure are discussed further at ALLERGY TESTS.
The combination of allergy testing limitations and occupant complaints that may in some cases justify a building survey for physical particles or other evidence of significant levels of problem allergens, molds, or other conditions is discussed at ALLERGY TEST LIMITATIONS.
See MOLD EXPERT, WHEN TO HIRE for advice on determining when it is appropriate and justified to order inspections and tests of a building for mold or allergens.
See BIOLOGICAL POLLUTANTS for information about recognizing and removing these indoor contaminants.
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Additional technical contributors & reference sources for this article are listed below.
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MedicineNet.com provides a detailed definition of ELISA at www.medterms.com/script/main/art.asp?articlekey=9099
ELISA testing accuracy: Here's a critique of ELISA
http://www.betterhealthusa.com/public/282.cfm - Townsend Letter for Doctors and Patients
The critique included in that article raises compelling questions about IgG testing assays, which prompted my interest in actually screening for the particles that could carry allergens - dog dander or cat dander in the case at hand.
http://www.tldp.com/issue/174/IgG%20Food%20Allergy.html contains similar criticism in another venue but interestingly by the same author, Sheryl Miller. Sheryl Miller, MT (ASCP), PhD, is an Immunologist and Associate Professor of Basic and Medical Sciences at Bastyr University in Bothell, Washington. She is also the Laboratory Director of the Bastyr Natural Health Clinic Laboratory.
Testing for the level of exposure to animal allergens is discussed at http://www.animalhealthchannel.com/animalallergy/diagnosis.shtml (lab animal exposure study is interesting because it involves a higher exposure level in some cases)
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
Kansas State University, department of plant pathology, extension plant pathology web page on wheat rust fungus: see http://www.oznet.ksu.edu/path-ext/factSheets/Wheat/Wheat%20Leaf%20Rust.asp
"A Brief Guide to Mold, Moisture, and Your Home",
U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
US EPA - Mold Remediation in Schools and Commercial Building [Copy on file at /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
US EPA - Una Breva Guia a Moho - Hongo [Copy on file as /sickhouse/EPA_Moho_Guia_sp.pdf - en Espanol
Allergies, Allergens, Allergy Testing in buildings - References & Products
Allergen Tests in buildings advice about how to test, what to look for, in evaluating the level of dog, cat, or other animal allergens in a building
"IgG Food Allergy Testing by ELISA/EIA, What do they really tell us?" Sheryl B. Miller, MT (ASCP), PhD, Clinical Laboratory Director, Bastyr University Natural Health Clinic - ELISA testing accuracy: Here is an example of Miller's critique of ELISA
http://www.betterhealthusa.com/public/282.cfm - Townsend Letter for Doctors and Patients
The critique included in that article raises compelling questions about IgG testing assays, which prompts our interest in actually screening for the presence of high levels of particles that could carry allergens - dog dander or cat dander in the case at hand.
http://www.tldp.com/issue/174/IgG%20Food%20Allergy.html contains similar criticism in another venue but interestingly by the same author, Sheryl Miller. Sheryl Miller, MT (ASCP), PhD, is an Immunologist and Associate Professor of Basic and Medical Sciences at Bastyr University in Bothell, Washington. She is also the Laboratory Director of the Bastyr Natural Health Clinic Laboratory.
Allergens: Testing for the level of exposure to animal allergens is discussed at http://www.animalhealthchannel.com/animalallergy/diagnosis.shtml (lab animal exposure study is interesting because it involves a higher exposure level in some cases
Allergens: WebMD discusses allergy tests for humans at webmd.com/allergies/allergy-tests
Animal Allergens: Dog, Cat, and Other Animal Dander - Cleanup & Prevention Information for Asthmatics and regarding Indoor Air Quality.
Recognizing Allergens: What various indoor allergens look like - identification photos to help identify pollen, dust mites, animal dander, toxic or allergenic mold - Common Mold and other Allergens, Irritants, Remedies & Advice
Rodent control issues, including dander, fecal, and urine contamination of buildings and Building insulation are discussed at our
Associations: Sick House, Sick Building, SBS - Air Quality, Government, Private Associations and Information Resources
Atlas of Clinical Fungi, 2nd Ed., GS deHoog, J Guarro, J Gene, & MJ Figueras, Centraalbureau voor Schimmelcultures, Universitat Rovira I Virgili, 2000, ISBN 90-70351-43-9 (you can buy this book at Amazon) - The Atlas of Clinical Fungi is also available on CD ROM
Atlas of Indoor Mold, Online Clinical Mold Atlas, Toxins, Pathogens, Allergens and Other Indoor Particles - Medical Health Effects of Mold (separate online document)
Black Mold that is Harmless Photos of recognizable, usually harmless black mold on wood, bluestain, ceratocystis, ophistoma
Building Floods: quick steps after a building flood or plumbing leak can prevent costly mold contamination
Classes of Mold: what types of cosmetic, allergenic, or toxic mold are a problem? Can mold be cleaned-up successfully?
"A Brief Guide to Mold, Moisture, and Your Home", U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
"Disease Prevention Program for Certain Vegetable Crops," David B. Langston, Jr., Extension Plant Pathologist - Vegetables, University of Georgia (PDF document) original source: www.reeis.usda.gov/web/crisprojectpages/209797.html
"Disease Prevention in Home Vegetable Gardens,"
Patricia Donald,
Department of Plant Microbiology and Pathology,
Lewis Jett
Department of Horticulture, University of Missouri Extension - extension.missouri.edu/publications/DisplayPub.aspx?P=G6202
Fifth Kingdom, Bryce Kendrick, ISBN13: 9781585100224, is available from the InspectAPedia online bookstore - we recommend the CD-ROM version of this book. This 3rd/edition is a compact but comprehensive encyclopedia of all things mycological. Every aspect of the fungi, from aflatoxin to zppspores, with an accessible blend of verve and wit. The 24 chapters are filled with up-to-date information of classification, yeast, lichens, spore dispersal, allergies, ecology, genetics, plant pathology, predatory fungi, biological control, mutualistic symbioses with animals and plants, fungi as food, food spoilage and mycotoxins.
Ozone Warnings - Use of Ozone as a "mold" remedy is ineffective and may be dangerous.
Rot concerns in buildings-some building mold such as Meruliporia incrassata "Poria" risks serious rot and hidden structural damage
US EPA: Una Breva Guia a Moho - Hongo [Copy on file as /sickhouse/EPA_Moho_Guia_sp.pdf - en Espanol
OTHER IAQ ISSUES: How To Find and Address Other Indoor Air or Indoor Environment Contaminants Besides Mold
Mold or allergens may not be the only or even the main indoor environmental contaminant. Don't let media attention to mold
cause so much enviro-scare fear that other, possibly more urgent hazards go un-addressed.
Ozone Warnings - Use of Ozone as a "mold"
remedy is ineffective and may be dangerous.
Pet control - if you can't say goodbye to your bird, cat, dog, guinea pig, hamster, tropical fish, then limit the
areas they occupy and limit the airflow from that area to sleeping or other areas of the building, use allergenic
bedding, eliminate wall-to-wall carpeting, improve housecleaning including use of a HEPA-rated vacuum cleaner. For more details
see our article Dog, Cat, and Other Animal Dander - Information for Asthmatics and Indoor Air Quality
Rodents, Mice, Squirrel Control - I find high levels of mouse and rodent dander, fecal dust, and urine-contaminated dust in some buildings,
and high levels of these materials in building insulation in those locations. If you have a mouse problem, particularly if mice and their waste (fecals or urine) are contaminating
the building HVAC or building insulation, may need both steps to clean up or remove infected materials and steps to stop an ongoing
rodent problem. If squirrels are a problem, the cleanup needs to include closing off entry openings into the building. Get some
help from a licensed pest control expert.
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