Expert advice

Nearly 20 million people (about 9 million of them children) in the United States suffer from asthma, according to the National Institutes of Health. An asthma attack or episode can include symptoms such as wheezing, coughing and difficulty breathing. And summer, with its heat and high humidity, can be a particularly difficult season for those who have the chronic disease, says Dr. John Bacon, an allergy, asthma and immunology specialist at St. Joseph Medical Center in Towson.

Why are the summer months difficult for asthma sufferers?


Asthma triggers include pollen, animal dander, dust mites, cigarette smoke, respiratory infections like the common cold and exercise, particularly in cold weather. In the spring, there's a lot of grass and tree pollen about. Then there's a drop-off of pollen in midsummer, but that is followed in August by the ragweed season beginning and peaking around Labor Day.

And a Hopkins study found that cockroach allergens were the No. 1 indoor allergen in Baltimore City and dust mites were No. 2. Humidity encourages the growth of such allergens. In fact, high humidity is a requisite for dust mites.


What steps can those with asthma take, particularly in the hot months, to ward off or alleviate their symptoms?

Air conditioning is their friend, for several reasons. It lowers humidity, which decreases mold growth, cockroaches and dust mites indoors. And you can keep your windows shut, which keeps pollen from blowing in.

There are other things, too: Don't hang your clothes outside to dry; they'll pick up pollen. And shower in the evening. By the end of the day you are covered in pollen.

What causes asthma?

There is a genetic predisposition to asthma, and there is a large connection to the environment. So if the person is genetically susceptible and if they receive an appropriate environmental stimulus they will go on to develop asthma.

There is a theory that the decreased levels of exercise and dietary factors may play a role.

Some scientists have suggested that we've become too clean for our own good. That the lack of exposure in early life to infections and various microbes may be making children more prone to asthma. Should we really be dirtier?

That's the "hygiene hypothesis" that says that by living in such clean environments with antibacterial soaps and ultra-pasteurized foods and smaller family sizes, youngsters aren't exposed to as many infections and so tend to grow up more prone to develop allergies.


Some studies suggest that the presence of pets in the home, particularly dogs, many dogs, help with this. Like the more pets you have, the better, and the best seems to be if you have pets while you're pregnant. But this is still an active area of research, so I don't tell people to go get a dog.

What do you tell patients when they are first diagnosed with asthma?

Asthma can be controlled, it can't be cured. We achieve control in three [ways]:

Environmental control measures (such as eliminating or avoiding allergens with dust-proof covers for your bed pillow, mattress and box spring; no carpets; keeping indoor humidity at 30 to 50 percent; using air filters; and eliminating smoking in the home).

Medications, particularly anti-inflammatory measures (which may come as inhalers or tablets).

And allergy injections.


Holly Selby