post-title Allergens for Every Season: Winter Allergies 2012-11-28 14:43:30 yes no Posted by

Allergens for Every Season: Winter Allergies

by Joseph Bullock, M.D. Recent global warming has had a negative effect upon people with respiratory allergy symptoms. Global warming has had an effect upon the intensity and duration of the pollen seasons. Normally, the tree pollen season occurs from mid- April until the end of May. Usually there is a substantial frost around “income tax day” (April 15) […]

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by Joseph Bullock, M.D.

Recent global warming has had a negative effect upon people with respiratory allergy symptoms. Global warming has had an effect upon the intensity and duration of the pollen seasons. Normally, the tree pollen season occurs from mid- April until the end of May. Usually there is a substantial frost around “income tax day” (April 15) which markedly blunts the production of tree pollen. Last Spring, there was no such frost, and the tree pollen counts were so high that some cities reported pollen counts five to ten times record highs. Grass pollen season occurs from mid-May to the end of June. Its abundance is influenced by rain, which washes pollen out of the air. Last year’s drought encouraged very high grass pollen levels.  The “dog days of summer” (early July to mid August) usually bring high humidity which encourages outdoor mold growth. When the sun starts shining on the Earth at a certain angle around August 15, the giant and dwarf ragweed plants start to pollinate. The abundance of pollen in the ragweed season is again encouraged by drought conditions.

In past years, the ground outdoors was almost totally frozen from November to March, killing all outdoor pollens and molds. In recent years, however, there has been more freezing and thawing in the late Fall and Winter, with longer periods of warmer than normal temperatures. This warmer climate has allowed outdoor molds to survive during the winter and thus cause respiratory allergy symptoms in patients allergic to molds even in the heart of the winter. Last Winter was a good example of this.

When Winter comes, if it is cold enough, some allergy sufferers feel better, but some may actually get worse. During Winter, very cold weather and the dry heat in the house eliminate molds, but we tend to stay indoors more with the forced air heat blowing, and we are more exposed to dust mites and indoor animal dander. Dust mites (dermatophagoides pteronyssinus and farinae) are microscopic, eight-legged creatures which live in our bed and bedding and eat our dead skin scales (keratin).  Dust mites are present in all indoor environments, and are not to be confused with “bed bugs.” They excrete waste products, fecal pellets, and eggs which, when inhaled, cause respiratory allergy symptoms. Symptoms from dust mite allergy may be worse through the night and first thing in the morning, as dust mite allergen is inhaled from the bed all night long. Dust mite allergy may not cause as much itching or sneezing as pollen allergy does. Many people who suffer from dust mite allergy also develop significant congestion, post nasal drainage and sinus pressure and headaches.

The following measures are effective in reducing or eliminating dust mite exposure:

  1. Encase the mattress, box springs, and pillows in commercial allergen proofencasings. These can be found at most home goods stores.
  2. Wash and electric dry all bedding (sheets, pillow cases, blankets and mattress pads) in hot (130 degrees Fahrenheit) water weekly. Only hot water will denature the dust mite allergens.
  3. Wash and electric dry children’s’ stuffed animals, and try to limit the number of stuffed animals in the bed.
  4. Remove carpeting in bedroom or vacuum with a HEPA filter vacuum cleaner.
  5. High humidity (70-80%) encourages dust mite growth, so keeping the indoor relative humidity around 40-50% helps.

Animal danders are a second cause of indoor allergen exposure. In cases of animal dander allergy, it is optimal to remove the animal from the house. We understand that this is not always possible, and a compromise may be to keep the animal out of the major living areas of the house, ideally in a basement, garage or separate room.  It is definitely worthwhile to keep the animal out of the bedroom and run a HEPA filter in the bedroom with the door closed. Bathing of dogs twice a week may be effective. Unfortunately, bathing of cats does not appear to be terribly effective.  Special soaps and anti-dander sprays and shampoos that claim to render the animal less allergenic have no proven efficacy. There are numerous advertised breeds of “hypoallergenic” dogs and cats but, sadly, there are no scientific data to support the concept of “hypoallergenic animals”.

Winter also brings more people together in the indoor environment which encourages the sharing of viral respiratory infections and increases exposure to environmental tobacco smoke. These aggravate existing allergy symptoms and encourage sinusitis and bronchitis in patients with allergies. Atopic dermatitis (also known as eczema) is an allergic disorder that also may worsen in the winter due to dry air, dust mites, and increased animal dander exposure.

As you can see, there are allergens for every season!

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