Cypresses are the oldest plants that exist on Earth. In Spain there are several species of cypress, of which the most important are the common cypress (Cupressus sempervirens), the Arizona cypress (Cupressus arizonica) and the Monterrey cypress (Cupressus macrocarpa).
What species of cypress is the most frequent?
The common cypress is the most widespread, well-known species and also the tallest of all. It is also the longest-lived species, being able to live more than 500 years. There are two varieties of common cypress, the most frequent is the narrow crown, almost columnar. It is characterized by its vertical growth. This variety is very common to find in cemeteries, monasteries and churches.
In our area the most frequent species is the common cypress. This is partly due to the fact that it is native to the eastern Mediterranean and to the fact that in recent years its presence as an ornamental tree in parks, gardens and hedges in homes has increased.
Why does cypress pollen cause allergy?
Pollen is the male spore of plants and contains all the genetic information needed to complete fertilization. Pollen also has allergenic proteins. These are inside but can escape into the atmosphere by passing through their pores and micropores or by breaking the pollen itself.
Pollens after release (pollination) are suspended in the atmosphere at the mercy of the wind. This facilitates their transport from areas of high concentration to areas of low concentration. If pollen, or its allergenic proteins, comes into contact with allergic patients, it can cause respiratory allergy symptoms. Windy days, rain and thunderstorms favor the breakdown of pollen by increasing exposure to allergenic proteins.
When do cypress trees pollinate?
Cypress trees can pollinate at almost any time of the year, but late winter to early spring is considered to be the most pollinated months. In our area it is common to find high levels of cypress pollen between February and March.
In general, pollen is usually affected by the “sweeping” effect produced by rainfall, but in the case of cypress pollen its levels tend to be higher in years with more rainfall.
Is allergy to cypress pollen common in our area?
No, allergy to cypress pollen is not very common in our area. In the case of allergic rhinitis, it is the fourth most important pollen in Catalonia, far behind the pollen of grasses, plane trees and olive trees. It is estimated that in our area cypress pollen is responsible for 22% of cases of allergic rhinitis and 14% of cases of allergic asthma.
What symptoms does cypress pollen allergy produce??
The symptoms of allergy to cypress pollen are respiratory: rhinitis and asthma.
Patients with rhinitis have sneezing, nasal itching, liquid mucus and nasal congestion. Symptoms appear during the day, especially in open environments. Symptoms usually subside at night, or indoors. Pollen can also affect the eyes causing itching, redness and tearing (allergic rhinoconjuntivitis). Some patients may also have asthma symptoms, such as cough, shortness of breath, chest tightness, and wheezing.
Patients allergic to cypress pollen usually have more severe symptoms than those patients allergic to other types of pollens.
What can I do to avoid cypress pollen?
he best measure is to stay indoors for as long as possible during the days of greatest pollination.
At home, do not open the windows first thing in the morning or when the sun goes down. Try not to hang clothes outside, especially on days of high exposure, since pollen can get trapped in the clothes. It is preferable to wash the pollen from the terraces rather than collect it.
When you go outside, wear sunglasses so that pollen cannot come into contact with your eyes. Avoid outdoor activities first thing in the morning and late in the afternoon. If you are going to be outdoors for a long time, when exposure levels are high, the use of masks (FPP2) is recommended.
When traveling by car, do so with the windows closed. Use anti-pollen filters in the air conditioning of the car.
Cypresses, unlike other trees, can produce pollen from the foot of the plant to the top. Pollen is grouped into small brown sacs located at the ends of the branches. It is for this reason that pruning before the pollination season can reduce exposure if you live in close contact with these trees.
How does pollution and climate change affect cypress pollen?
Greenhouse gases (CO2, NO2, etc.) are increasing the global temperature. The increase in temperature is producing pollens with more allergenic proteins. The absence of rain is bringing forward the pollination season.
In the particular case of cypress pollen, the increase in temperature during the winter is producing an earlier pollination. In pollen collectors it is increasingly common to find broken pollen grains which suggests that patients are increasingly exposed to greater amounts of allergenic proteins. There are studies that have shown that these allergenic proteins could be modified due to pollution-induced stress creating more reactive proteins, with greater capacity to induce allergy symptoms.
From ClinicAL we hope to have provided information about allergy to cypress pollen, a very frequent allergy in the last weeks of winter and early spring.
Dr Federico de la Roca
Especialista en Alergología.