With a new heat wave arriving combined with the dry weather, common at this time of year, respiratory allergies are gaining strength. Asthma and rhinitis are among the most prevalent. The reduction in air humidity, which is generally below 30% at this time of year, combined with conditions of less atmospheric dispersion of gases and particulate materials, irritates the airways, predisposing to infectious conditions. In Brazil, the seasonality pattern varies between regions, being more marked in those with better defined climatic seasons, such as in the South, Southeast and Center West.
Dr. Maria Cândida Rizzo, member of the Rhinitis Scientific Department of the Brazilian Association of Allergy and Immunology (ASBAI), explains below which diseases are most common at this time of year, the treatments available and how to prevent winter allergies.
Which diseases are most common during these periods?
Influenza is a typical example of greater transmissibility in the winter months, which is why vaccination campaigns begin in the autumn months. In addition to the influenza virus, all other respiratory viruses are included in this context, such as rhinoviruses, adenoviruses, coronaviruses, mouthviruses, metapneumoviruses and others.
What age group is most susceptible to these diseases?
These are children and the elderly. In children there is immunological immaturity proportional to the age group and in the elderly the responses tend to be slower and often insufficient. This has been applied to most viral and bacterial infectious agents with the exception of the new coronavirus, where a smaller number of illnesses were observed in healthy children. The explanation comes from the fact that the child has a good innate immune response (which is ready since birth), which is important in defending against coronavirus. As for immunodeficient people (primary or secondary to treatments), this is a group that is extremely vulnerable to clinical complications when infected, due to a lack of immunological defenses.
And allergic respiratory diseases, which ones can we highlight?
I highlight rhinitis and asthma. Allergic rhinitis is more common after the age of 2 and affects around 26% of Brazilian children. In adolescents, this percentage reaches 30%, according to data from ISAAC (International Study of Asthma and Allergies in Childhood), applied in several Brazilian states.
Rhinitis symptoms are characterized by frequent itching in the nose and/or eyes, repeated sneezing, especially in the morning and at night, frequent coryza (runny nose) and nasal obstruction, even in the absence of colds.
I also highlight the asthma, which affects around 10% of the Brazilian population and is the cause of death for approximately two thousand people per year. It is a chronic inflammatory disease of the respiratory tract that can be caused or intensified by several factors such as dust mites, mold, pollens, respiratory virus infection, excess weight, rhinitis, gastroesophageal reflux, medications and genetic predisposition. From children to young adults, allergies are important factors in causing asthma attacks.
Is it possible to prevent these winter respiratory illnesses?
The most effective form of prevention is to have an up-to-date vaccination record. We can also prevent infections by trying to avoid poorly ventilated environments with lots of people.
Another important recommendation is the control of chronic diseases, whether respiratory or not. For example, asthma and rhinitis, which tend to be more severe during cold times of the year, and if they are not under control, viruses and bacteria will certainly cause a greater inflammatory process, often leading to serious respiratory conditions.
Other chronic diseases such as high blood pressure and diabetes must also be controlled to avoid worsening respiratory infectious processes. During the new Coronavirus epidemic, this fact was highlighted and many deaths occurred in these patients with comorbidities, especially uncontrolled ones.
