I swear that I have not been cultivating ragweed. It grows naturally and loves fields, upturned sole, the sides of the road and developing land. Some of our Giant Ragweed plants are more that 9 feet tall! It is a bumper crop this year.

Giant ragweed has a very typical leave and those large anthers (?) from which that yellow pollen falls and becomes airborn. The species is called  ambrosia- for those allergic to ragwee, truly not a drink of the gods but a real source of respiratory and ocular misery.

Short ragweed is the most problematic for allergic individuals. The specific proteins in each species does vary, but they do share a number of allergenic proteins.

                                                 Short Ragweed                                                   Ragweed pollen

Why House Dust Avoidance is Hard

Another way to title this is ‘Why allergists can be meanies’. How could we even think of shattering such a peaceful, tranquil, and sweet image? I wonder if this is the more commonplace reality of young children and stuffed animals.

A colleague of mine, Dr. Veda Ackerman once told me that an allergist can never give a talk without saying something about house dust mites and/or showing a picture of a house dust mite. She is probably correct on that.

The simple retort is that house dust mites are important allergens. Individuals can be sensitized and allergic to proteins in the fecal pellet of the house dust mites. Yes that is where the allergen is found in feces (also known by a number of other terms not allowed on this site). I recall the look of horror when a patient on oral drops from house dust mites realized the source of the allergen.

In the lore of allergy, it has been said that inch for inch that there are more house dust mites in stuffed animals than any other item manufactured by mankind. Given that fact, when there is sensitization to house dust mites and this is suspected as a reason for allergy symptoms, the most effective therapy is avoidance of the house dust mite. So the recommendation is the removal of the stuffed animals from the child’s environment. There are a few other options; placing the stuffed animal in the freezer over night once a week or dry cleaning the critter. I fear that in this situation, the freezer would be filled to capacity with these friends.

 This picture of my granddaughter clearly shows why advising avoidance of stuffed animals can be a problem. It is often said that more than one stuffed animal in the bed with a house dust mite sensitive/allergic individual is too many.  Fortunately Stella has no allergic conditions. This picture is precious. My daughter labels it as ‘Stella and her friends’.

Stella’s Papa

FEL

When I was at Henry Ford Hospital, Dennis Ownby, MD analyzed the house dust material that was used in the immunotherapy program. Of note is that there was more cat allergen in the house dust mix than what was available in the cat preparation that was available at the time. This house dust extract came from homes. I learned that dust is a mixture of many things.

During my fellowship we went on a field trip across the state of North Carolina to Greer labs. The house dust used for allergen diagnostics and for treatment sets came from collections from a large number of homes. The house dust extract had cat, dog, house dust mite fecal material, roach, other insects, food, mold, and IgA from human spittle.

The June issue of the journal Pediatrics had a quip from the editor emeritus, Jerold F. Lucey, MD regarding the ‘Dirt on Dust’. Dust is a big deal in allergy so this interested me. The note starts with the statement that simple house dust may not be as simple as all that. His source was a text box by Andrew Grant which was part of a more elaborate article by Michael Tennesen in the May 2010 issue of Discover magazine.

Mr. Grant reports that we are responsible for our own house dust. A scientific analysis of house dust reveals that it contains fibers from clothing, crumbs from food, and human dander. Hopefully, so far this is not too disgusting.

House dust has the remnants of other living creatures- plants, bacteria, mold, fungi, decaying insect carcasses, and fecal droppings from house dust mite (yes that is poop!). Had enough? It gets worse.

Our open windows and our shoes bring in the chemical villains. A study by the US Geological Survey from January, 2010 reported on numerous harmful chemicals discovered in house dust. Included in the samples were polycyclic aromatic hydrocarbons. This is used to coat parking lots. DDT, a pesticide banned 40 years ago was detected in house dust samples. Reference was made to another study in which arsenic and lead contaminated soil was found in house dust samples. The lesson here is that we track it in to our home on our shoes.

Clearly, dust is not so simple. It is a hodgepodge of items- biological and chemical. Some can elicit an allergic response; some can cause illness in other ways.

This has caused me to wonder about dust. My wonderment has lead to a few questions;

• If the house dust has all this stuff from our shoes, I wonder what is lurking on the mat at the front door?
• Are there enough food particles in house dust to trigger an allergic reaction in someone sensitive to food?
• What is the composite listing of what is in house dust? Endotoxins would be on that list.
• What is the seasonal variation in house dust composition?
• How do various methods of cleaning change what is in house dust? Now that we have been scared, what can we do about it?
• Are certain types of homes more conducive to certain dust components.

Good studies and information always beget more questions. I am now removing my workday shoes prior to walking into my home!

Fred Leickly