Allergy Alert! Arizona Ragweed

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Arizona Ragweed pollen is reaching it’s peak this April.  Pollen counts are unusually high because of the rainy, wet winter and the windy, warm, dry spring.  These conditions are likely to continue through April and most of May.  Although the summer heat will put an end to ragweed pollen production in the valley deserts by late May to June,  pollen can travel for thousands of miles and so plants growing at higher elevation such as the Catalina Mountains and Mogollon Rim area will affect residents of Phoenix until mid summer.

Desert Ragweed South Mountain

There are an estimated 41 species of Ragweed found around the world.  Many varieties of ragweed are adapted to the arid desert environment with an estimated ten species found in the Sonoran desert. In contrast to ragweed varieties found in the Coastal, Midwestern and Southern regions of the United States, desert varieties of ragweed typically pollinate in the spring rather than late summer to fall.

The most important varieties of ragweed affecting the communities of Chandler, Ahwatukee, Queen Creak, and Tempe,  are Rabbit Bush (ambrosia deltoidea), Desert Ragweed (ambrosia dumosa), and Canyon Ragweed (ambrosia ambrosioides).  Burro brush pollen (hymenoclea salsola) may cause problems in individuals sensitive to ragweed.

House Dust Allergy

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Many people recognize allergy symptoms such as a runny or stuffy nose, itchy, watery eyes and sneezing (allergic rhinoconjunctivitis) from dust exposure related to common household chores such as vacuuming, sweeping, and dusting. House dust exposure can also trigger asthma symptoms such as wheezing, coughing, chest tightness and shortness of breath.

Why does house dust cause allergic reactions?

House dust is a mixture of many substances. Its content may vary from home to home, but the most common allergy triggers are:
·         Dust mites
·         Cockroaches
·         Fungi (Mold)
·         Animal Dander (house pets as well as rodents)
Being ” allergic” to these components of house dust means that your immune system produces antibodies called Immunoglobulin E (IgE), that react with  proteins unique to the substance.  Exposure to only small amounts of the offending allergen produces an allergic inflammatory response and allergy symptoms.

Is dust allergy a sign of a dirty house?

No. A dirty house can make a house dust allergy problem worse, however. Normal housekeeping may not be enough to get rid of house dust allergy symptoms. This is because many of the substances in dust cannot be removed by normal cleaning procedures. Vigorous cleaning methods can actually put more dust into the air making symptoms worse. Even if the house is very clean, some people are so allergic that even minimal exposures may trigger their symptoms.

Dust Mite Allergy

Dust mites are the most common cause of allergy from house dust. They belong to the family of eight-legged creatures called arachnids that also include spiders, chiggers and ticks. Dust mites are hardy creatures that live and multiply easily in warm, humid places. They prefer temperatures at or above 70 degrees Fahrenheit with a relative humidity of 75 percent to 80 percent. They die when the humidity falls below 40 percent to 50 percent. They are not usually found in dry climates.

Dust samples from homes in Arizona rarely contain significant levels of house dust mite.  These is an exception however.  Home that use evaporative coolers have humidity levels high enough to support house dust mites.  It is also possible that using a room humidifier regularly will increase humidity to levels that will encourage mite infestation.
High levels of exposure to dust mite are an important factor in the development of asthma in children. People who are allergic to dust mites react to proteins within the bodies and feces of the mites. These particles are found mostly in pillows, mattresses, carpeting and upholstered furniture. They float into the air when anyone vacuums, walks on a carpet or disturbs bedding, but settle out of the air soon after the disturbance is over.
Dust mite-allergic people who inhale these particles frequently experience allergy symptoms. There may be many as 19,000 dust mites in one gram of dust, but usually between 100 to 500 mites live in each gram. (A gram is about the weight of a paper clip.) Each mite produces about 10 to 20 waste particles per day and lives for 30 days. Egg-laying females can add 25 to 30 new mites to the population during their lifetime.