“My Worst Allergy Spring Was the Winter I Just Spent in Arizona”: Part Two

Arizona Ash Flower

While walking my dog several weeks ago, I noticed something unexpected; a number of ash trees in full bloom.   This was unexpected because it was the first week of February and ash trees usually pollinate later in the month.  It was also unexpected because this was near a school in the Foothills of Ahwatukee were the ash trees are supposed to be of a less allergenic variety.   This is in distinction from the Arizona Ash, Fraxinus velutina, which is notorious for it’s prolific production of allergenic pollen. For this reason landscapers have been discouraged from planting Arizona Ash trees for a number of years although they are very numerous in older communities such as the Warner Ranch area as well as old Ahwatukee and Tempe.

Ash trees are in the same family as olive trees, possible the most allergenic tree in Phoenix, and so people who are allergic to one will be allergic to the other

So the ash trees are pollinating a full two to three week early this year, probable because of the warm weather.  This along with large amount of Arizona Cypress and Juniper pollen in the air is creating a very difficult winter for people with allergies.

“My Worst Allergy Spring Was the Winter I Just Spent in Arizona”

When we think of allergy season, fall and spring comes to mind, but not so much winter.  Yet this December, January, and now into February, patients have been coming into our allergy clinic in the suburbs of Phoenix complaining of some of the worst allergy symptoms all year.  Typical complaints include sneezing, itchy nose, and particularly, very itchy eyes.

Alligator Juniper

Alligator Juniper Payson, Arizona

When patients undergo testing for allergies, many show sensitivity to a number of different allergens such as plant pollen, mold, foods, and animal dander.  However, in the case of the winter allergy sufferers, the majority show sensitivity to only one thing: juniper, or more specifically, Cupressaceae.

The Cupressaceae are a family of evergreen conifers found throughout the world. Arizona is home to a number of native species of cupressaceae including Rocky Mountain Juniper (Juniperus scopulorum), Utah Juniper (Juniperus osteosperma), One Seed Juniper (Juniperus monosperma), Alligator Juniper (Juniperus deppeana) and Arizona Cypress (Cupressus arizonica).

Although Phoenix has a number of ornamental varieties of Cupressaceae used in landscaping, the majority are found at 3000-7000 feet elevation and cover millions of acres surrounding Phoenix on all sides.    When conditions are right, a large amount of cupressaceae pollen finds its way into the valley.  One of the chief offenders is Arizona Cypress which is very prevalent in the higher areas surrounding the valley and produces  pollen November through March.

The pollen produced by the different varieties of Cupressaceae cross react with one another, which means that if you are allergic to one you will be allergic to all.  Mountain cedar (Juniperus ashei) is the leading cause of respiratory allergy in South Texas and affects so many with severe allergy symptoms that it has been given it’s own diagnosis, “cedar fever” .

Oral Desensitization for Peanut Allergy

This week the Lancet reported results of an oral desensitization study in children with peanut allergy.   Peanut allergic children age 7-16 were gradually exposed to increasing oral doses of peanut over a six month period.  The goal of the study was to achieve a level of desensitization that would allow the children to safely ingest 1400 mg of peanut protein (about 10 peanuts) without symptoms.

At the end of the study period, 62% of the children had reached the target goal and were able to tolerate 1400 mg of peanut protein. 84% were able to tolerate 800 mg of peanut protein, the equivalent of about five peanuts.  In the untreated control group, none of the children were able to tolerate the full dose of peanut protein.  Side effects in the group receiving peanut including vomiting, itching of the mouth and wheezing.  One child had an allergic reaction to the peanut severe enough to require an injection of epinephrine.

This is another study showing that oral desensitization to peanut in peanut allergic children can be successful and relatively safe.  The process does require significant time and effort and is associated with some risk.  It is a procedure that cannot be undertaken at home and requires careful monitoring in an allergy specialist’s clinic or hospital setting.

Is it worth the effort?  Currently, oral desensitization may significantly reduce the risk of a life threatening allergic reaction occurring in a peanut allergic child who is exposed to peanut by mistake.   The procedure is not a cure and does not allow children to enjoy peanut butter or a granola bar without concern of a reaction.