Desert Ragweed (Ambrosia dumosa)

Desert Ragweed (Ambrosia Dumosa)

Desert Ragweed is a small shrub (2 ft) found throughout the Sonoran desert.  It is dormant throughout most of the year but comes to life during the spring, particularly if winter rains have been substantial, sprouting leaves and flowers until the heat of summer sets in.  In some areas, depending on rainfall and elevation, Desert Ragweed may pollinate in the fall as well as spring.  It is one of the most prevalent varieties of Ragweed in South Mountain Park and desert areas surrounding Ahwatukee.

Pollinates: March-May


Rabbit Bush (Triangle Leaf Bursage)

Rabbit Bush (Triangle Leaf Bursage)

Rabbit Bush (Triangle Leaf Bursage) is a member of the ragweed family. It is native to the Sonoran desert and is one of the most commonly encountered plants in South Mountain and McDowell Mountain Parks. It has been used in desert landscaping as a hardy, drought tolerant shrub.

Pollinates: February-May


Canyon Ragweed (Ambrosia ambrosioides)


Canyon Ragweed (Ambrosia ambrosioides)

This large plant can grow to 6 feet and is common throughout southwestern Arizona and the southern half of Baja California. It can be found in desert washes, irrigation canals, and road sides. The flower is wind-pollinated and the pollen can cause allergy symptoms in individuals sensitive to other varieties of ragweed.

Pollinates: March-June


Burrobrush (Hymenoclea salsola)

Burro Brush

Burro Brush (Hymenoclea salsola)

Burro Brush, also called White Burro Brush, is found throughout the Sonaran desert of Arizona.  It is wind pollinated, and a significant cause of allergy symptoms in the spring.

Pollinates: March-April


Mistaken asthma

There is a common saying among doctors that treat asthma: “Not all that wheezes is asthma and not all asthma wheezes”.   This is to remind us to be on the look out for conditions that look like asthma but may not be.

One of the most common asthma mimickers is a condition known as vocal chord dysfunction.  When we speak or sing, the vocal chords tighten and vibrate as a small about of air passes through the narrow opening.   The vocal cords are relaxed during normal breathing, allowing air to easily pass through the trachea.  In a condition called vocal cord dysfunction, the vocal cords and surrounding structures close together, or constrict, during one or both parts of the breathing cycle, partially blocking the windpipe and creating a sensation of not getting enough air.   The symptoms of vocal chord dysfunction are very similar to asthma: shortness of breath, chest tightness, and wheezing.  In fact, patients with vocal chord dysfunction are frequently treated with strong asthma medications including steroids for years before the proper diagnosis is made.

So what causes the vocal cords to tighten during normal breathing?  In many, vocal cord dysfunction is a type of involuntary stress reaction.  The vocal cords tighten during periods of stress.  This may be the case even though an individual does not feel particularly stressed or anxious. Vocal cord dysfunction had recently been recognized a frequent cause of exercise induced shortness of breath, particularly in children involved in school sports.  A child, who has a strong internal drive to win or feels pressure from a coach or parents to do better, may exhibit vocal chord problems.

The most important step in managing vocal chord dysfunction is suspecting it in the first place, particularly in someone who has been diagnosed and treated for asthma but is not responding to typical medications.    Effective treatment includes education and speech therapy.

When A Little Knowledge Can Be A Dangerous Thing

Food Allergy Blood Tests

Many parents are aware of the dangers of food allergies, however food allergy researchers are suggesting that strictly avoiding foods based on the results of an allergy test can make the problem worse.

Food allergy is common in young children. Just how common is unclear.  A recent report  in the Journal of Allergy and Clinical Immunology cited a review of over fifty studies  from around the world evaluating the prevalence of food allergy.   The result showed a disturbingly wide range of values with the frequency of milk allergy ranging from 1.2% to 17%, 0.2% to 7% for egg, 0% to 2% for peanut and fish, 0% to 10% for shellfish, and 3% to 35% for any food. Read more