What causes allergies?

At the beginning of the year, people reported an increase in allergies, having a runny nose and eye irritation.
image shows pollen grains
The image shows pollen grains. This year, the Mexican Aerobiology Network detected an increase of between 40% and 100% in pollen concentrations in different parts of the city. (Illustration: Getty Images)

Since the beginning of the year, citizens of Mexico City reported on Twitter an unusual increase in allergies, a runny nose, and eye irritation. Some speculated that this is due to pollution, which is constant in the city.

However, there are several factors that explain this increase. “Pollution does have an influence, but there are other things,” says María Teresa Burguete, an allergologist, immunologist, and pediatrician at the Zambrano Hellion Hospital of TecSalud.

“Allergies are a disease in which the body reacts drastically towards a harmless stimulus,” Burguete explains. This intense reaction can happen in the eyes, skin, nose, bronchi, or digestive system, depending on what a person is allergic to.

What causes allergies?

The sudden increase in people suffering from them, or their appearance in those who had never had them, maybe due to different things. One of them is the increase in pollen. This year, the Mexican Aerobiology Network (REMA in Spanish) detected an increase of between 40% and 100% in pollen concentrations in different sites in the city, with respect to 2022. The causes of this are still unknown, but they could be linked to climate change.

Other factors include sudden changes in temperature, genetic predispositions, and habits that cause inflammation and irritation, such as smoking. “The fact that this year and the past there were many viral infectious processes has an influence too,” says Burguete. With the resumption of everyday activities and meetings after the confinement due to the pandemic, viral infections have increased significantly.

Both pollution −which is more significant every year in Mexico City− and viral infections cause a degradation of the epithelium of the nose, leaving it more sensitive to the different pollens or mites that circulate in the air. All of this creates the perfect setting for allergies to skyrocket.

How do you recognize them and know when to visit a specialist?

The allergologist comments on several key points to distinguish between an allergy and the common flu. “There are moments where it’s difficult to distinguish one from the other,” she says, “with allergies, there’s general discomfort, but the patient does not present a fever, eats well, and is in a good mood.”

In addition, allergy symptoms usually concentrate on specific hours of the day. They generally first appear around noon, then disappear almost completely and reappear in the afternoon. With the flu symptoms are constant.

Although allergies are usually considered not-so-serious conditions, these have health effects that go beyond a runny nose. According to Burguete, the constant inflammation and irritation that allergies provoke can affect dream quality in children and adults, considerably reducing our quality of life. If we don’t sleep well, our memory, our ability to concentrate, our behavior, our humor, and our emotions can be seriously affected, she says.

In addition, allergies are usually chronic and keep getting worse over time, they do not disappear. “It is important to pay attention to the symptoms, be it the patient or their children,” Burguete warns.

If allergies stay in a person’s life for a long time, more than a few weeks, the expert says it’s time to visit a specialist, be it an allergologist or immunologist. “Waking up every day with nose congestion, waking up at night to clean your nose, or having to do your activities with a Kleenex bag is not normal,” she concludes.

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Inés Gutiérrez Jaber

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