La pollen allergy in Spain It has become a recurring issue every spring. Every year, millions of people notice how, almost without realizing it, sneezing, itchy eyes, and nasal congestion begin just as the days get longer and the weather improves. Although it may seem like "just" a seasonal annoyance, we are talking about a health problem that affects the quality of life, productivity, and even leisure time of those who suffer from it.
In our country, More than eight million people have pollen allergies.and around seven million are allergic to grassesThis figure also includes those who react to olive trees, Arizona cypress, plane trees, pellitory, or weeds like salsola and chenopodium. If you know which pollens are prevalent in your area, in which months they reach peak levels, and how they behave depending on the climate, you can anticipate and significantly reduce symptoms.
Main types of allergenic pollen in Spain
In Spain, there is not a single pollen responsible for the symptoms, but rather a set of plant species which pollinate throughout the year depending on the climate and region. Broadly speaking, tree pollen predominates in winter, grass pollen in spring, and pollen from various weeds in summer and autumn.
Pollen that can cause rhinitis, conjunctivitis, and asthma usually comes from plants of anemophilic pollinationThat is, they release their pollen into the air for the wind to carry. Therefore, it is not the large, showy flowers pollinated by insects (entomophilous) that most often cause respiratory allergies, but rather seemingly inconspicuous trees, shrubs, and grasses that are very efficient at dispersing pollen.
Grasses: the number one cause of allergies
The grasses (family Poaceae) are by far the main source of pollinosis in Spain. They include thousands of species, but it is the Pooideae subfamily that brings together most of the genera that are most problematic for allergy sufferers, such as Phleum, Dactylus, lolium o TrisetumThey are usually ordinary-looking weeds that grow on the edges of roads, cultivated fields, vacant lots and open spaces, which means they are everywhere.
In our country, grasses are the leading cause of hay fever in central and northern SpainIts flowering period is long, generally from April to July, although the exact distribution depends on each species and weather conditions. In regions such as Castile and León, Castile-La Mancha, Extremadura, and the interior of Levante and Andalusia, the total grass pollen load In spring, it is closely related to the rainfall between October and March: if the autumn-winter has been rainy, the season is usually more intense.
In the call “Green Spain” (Galician massif and Cantabrian coast) the presence of grasses is high, but the concentrations of pollen in the air are somewhat more moderate because the frequent rains during the flowering months wash the atmosphere and reduce, in part, the exposure.
Olive and Oleaceae family
The Oleaceae It includes several trees and shrubs, but only three have a significant influence on atmospheric pollen load: the ash (Fraxinus), the olive tree (Olea europaea) and the privet (ligustrumEach one has its pollination window: the ash usually releases pollen in February-March, the and the privet around July.
El olive It is the most important member of this group due to its prevalence and allergenic nature. It is very abundant in the mediterranean areaBoth in Spain and in other countries such as Italy, Greece, Türkiye, Portugal, and Israel. In our country, it is the second leading cause of pollen allergy after the grasses, with special relevance in Andalusia and in some areas of Castilla-La Mancha.
Jaén is a paradigmatic case: around 62% of its surface area is dedicated to olive cultivation, and it is estimated that approximately 95% of people with allergies People in the province show sensitivity to this pollen. High rates of sensitivity are also recorded in Córdoba, Seville, Málaga, Granada, Ciudad Real, and Toledo, where olive trees are part of the agricultural and urban landscape.
Parietaria and other nettles
Within Urticaceae. Of particular note is pellitory, a highly allergenic weed that proliferates in urban and peri-urban areas, especially on walls, fences, vacant lots, and ruins. The most relevant species on our Mediterranean coasts is Jewish parietariawhich produces large quantities of pollen capable of remaining in the environment for many months.
The pellitory has a very long pollination periodThis occurs approximately from February to November. This means that symptoms can appear across multiple seasons, leading to rhinitis or asthma that may be mistaken for chronic, non-allergic conditions. Furthermore, sensitization to this pollen is often diagnosed in people over 30, which is perplexing for those who have never had allergies before.
The provinces most affected by pellitory are Barcelona, Murcia and Valencia, where between 25% to 50% of patients with hay fever They test positive for this pollen. It is also significant in northern Spain: in A Coruña, sensitization has been described in 28% of the studied population, while in Bilbao the prevalence is around 4%.
Other relevant plants: cypress trees, plane trees, and weeds
The Arizona cypress, cypress and thuja trees (Cupressaceae family) are common in parks, hedges, and gardens. Their pollination is concentrated mainly in January and February, months in which many people begin to notice symptoms before spring has even arrived. They are responsible for a large proportion of winter rhinitis cases of allergic origin.
El plane tree (Platanus hispanica)This tree, widely used as an urban ornamental, releases a large amount of pollen in a relatively short but very intense period, mainly between March and April. Because it is found in streets, squares, and residential areas, exposure is direct and sometimes explosive: in a matter of days, pollen counts can skyrocket and cause acute outbreaks of symptoms.
Among the weedsBesides pellitory, other notable plants include plantains such as artemisia and other herbs that pollinate from April to July, and species such as chenopodium y Kali SalsolaThese pollens are very important in specific areas like Elche, where they are more prevalent than other pollens. These plants typically grow in agricultural fields, along roadsides, and in open fields, making them common in peri-urban and rural areas.
Geographical distribution of pollen in Spain
The combination of vegetation, climate, and land use makes the Pollen load varies greatly depending on the areaLiving on the Cantabrian coast is not the same as living in the Andalusian countryside, nor is living in a leafy neighborhood of a large city the same as living in an environment of olive or cereal crops.
At the peninsular center (Madrid, Castilla-La Mancha, Castilla y León, and part of Aragón) grasses, olive trees, plane trees, and cypress trees predominate. Spring here is often particularly intense for those with grass allergies, with clear peaks in May and June.
At Cantabrian coast, Navarre and La Rioja Grass pollen combines with that of birch, plane tree, and pellitory. The more humid environment means that concentrations can be more variable, but when dry and windy days coincide, the levels can be very bothersome.
At the mediterranean coast In Catalonia, the Valencian Community, the Balearic Islands, and Murcia, there is a strong presence of pellitory, grasses, olive trees, and plane trees. In these regions, the symptom period can last for many months, especially in people sensitized to several species simultaneously.
At the southern peninsula (Extremadura and Andalusia) are dominated by olive trees, grasses, and plane trees. The vast expanses of olive groves and cereal crops, along with increasingly irregular springs, mean that seasons classified as moderate, intense, or even extreme by the Spanish Society of Allergology and Clinical Immunology (SEAIC) are frequently expected.
The Canary Islands They exhibit a different pattern, with grasses, salsola, and pellitory being the most prominent. Depending on the island and weather conditions, there may be years with little grass pollen and others in which counts increase significantly, although recent forecasts generally point to rather mild springs in terms of this type of pollen.
How pollen levels and intensity categories are predicted
In Spain, the SEAIC works with the State Meteorological Agency (AEMET) and with the Pollen Collector Network distributed throughout the territory to produce annual forecasts. Data on temperature, precipitation, humidity, and historical pollen concentrations for each station are taken into account, applying statistical models developed in conjunction with the University of Castilla-La Mancha.
With this information, the following are established: intensity categories for spring based on the total number of grass pollen grains per cubic meter (m³) accumulated during the season:
- Mild Spring: less than about 4.000 grains/m³.
- Moderate Spring: between 4.000 and 8.000 grains/m³.
- Intense Spring: approximately between 8.000 and 12.000-15.000 grains/m³.
- Very intense or extreme spring: above 15.000-16.000 grains/m³.
These categories allow technical data to be translated into something useful for patients: knowing whether they are facing a “quiet”, moderately troublesome or potentially problematic year and adjust medication and corresponding prevention measures.
Typical forecasts by area and spring variability
Recent forecasts have shown a fairly recognizable pattern: in the southern peninsula The highest levels of grass pollen are usually expected, with potentially intense or extreme springs in provinces such as Badajoz, Cáceres, Seville, and Jaén. In some years, peaks of up to 16.000–19.000 grains/m³ have been estimated in certain locations in Extremadura.
At the peninsular center There is a great deal of variability: some areas have less than 1.000 grains/m³ (for example, some areas of Teruel, Zaragoza, or Huesca) and others have values exceeding 5.000 grains/m³, such as Toledo or Ciudad Real. Madrid is usually in an intermediate-to-high range, with springs classified as moderate or moderate-to-intense.
En Castilla y Leon A moderate spring is typical, although there can be years with significant peaks in certain provinces. In parts of Castilla-La Mancha (such as Guadalajara and Albacete) and in much of Aragón, grass forecasts usually indicate rather light levels.
At the northern peninsula (Galicia, Asturias, Cantabria, Basque Country) generally expect mild springs, with values around 1.500-2.000 grains/m³ in cities such as Bilbao, San Sebastián, A Coruña, Lugo, Pontevedra, Ourense, Santander, and Oviedo. However, some inland capitals like Vitoria may experience intense springs.
At the mediterranean arc (Catalonia, Balearic Islands, Valencian Community and Murcia) the forecasts for grasses are usually for mild springs, although the sum of other pollens (olive, pellitory, plane tree) can make the symptoms prolonged and significant for those who are sensitized to multiple allergens.
Duration of pollen allergy and pollination calendar
La duration of allergy The severity of allergies varies from person to person depending on which pollens they are sensitive to. Someone allergic almost exclusively to grasses may experience symptoms primarily from April to June, while someone allergic to cypress, plane tree, grasses, olive, and pellitory may suffer discomfort from January well into autumn.
To simplify, the pollination calendar In Spain, it tends to be organized as follows:
- January-February: Cupressaceae (Arizona cypress, cypress, thuja). In many cities, these months already bring serious problems with rhinitis and conjunctivitis.
- March-April: Plane trees, the beginnings of grasses in some areas, pine trees (although their pollen is less allergenic), and some weeds. This is a period when symptoms can suddenly appear.
- April-July: maximum of grasses and various weeds (including artemisia), with a clear association with spring rhinitis and asthma crises.
- May-June: peak of olive pollen, especially in Andalusia, Castilla-La Mancha and other inland and coastal Mediterranean areas.
- April-August: Urticaceae (pelliforms and nettle), with symptoms that can persist in Mediterranean coastal areas for months.
- July-September: Other weeds such as chenopodium or salsola are very important in certain semi-arid regions.
Each species maintains a relatively stable flowering pattern from year to year, but the amount of pollen emitted and its permanence in the air is greatly influenced by the weather of each season.
Impact of climate, climate change and pollution
Pre-spring weather conditions are key to defining the pollen season. Years with rainy autumns and winters These conditions favor more vigorous growth of grasses and weeds, resulting in springs with higher pollen concentrations. If this is combined with relatively mild temperatures and alternating periods of storms and dry weather, the pollen can remain suspended in the air for longer.
El climate change This is changing the landscape: rising average temperatures can lengthen pollen seasons and increase pollen production. It has also been observed that some pollen grains may contain higher concentrations of allergens, intensifying the immune response in sensitized individuals and increasing the likelihood of new allergies developing in the general population.
La atmospheric pollution It acts as an amplifier of the problem. Pollutants such as nitrogen dioxide (NO₂) or fine particulate matter (PM2.5) disrupt the protective barrier of the nasal mucosa, conjunctiva, and skin, facilitating the penetration of allergens. Furthermore, certain particles derived from combustion (for example, from diesel engines) can carry pollen antigens on their surface, allowing them to reach the deeper airways more easily and contributing to asthma attacks.
It is also known that some extreme episodes (such as intense thunderstorms) can fragment pollen grains, releasing smaller particles capable of reaching the bronchi within the lungs. These days, emergency departments often see spikes in asthma-related visits, especially among young patients with a marked sensitivity to grass pollen.
What is an allergy and how does hay fever occur?
Allergy is a exaggerated response of the immune system against substances that are normally harmless to most people. These substances, known as allergens, can be pollen, food, medications, dust mites, mold, animal dander, insect bites, and many more.
When an allergen first enters the body of a predisposed person, the immune system generates specific IgE antibodies against that element. These antibodies attach to the surface of cells called mast cells, which are very abundant in the nasal mucosa, bronchi, and conjunctiva of the eye.
In subsequent exposures, upon contact again with the same allergen, a reaction occurs binding reaction between the allergen and IgE from the surface of the mast cell. This triggers the release of inflammatory mediators such as histamine, leukotrienes, and other substances that are responsible for the symptoms: itching, sneezing, mucus, mucosal inflammation, bronchoconstriction, etc.
In the case of the pollinosis (Pollen allergy): The grains present in the air come into contact with exposed mucous membranes (nose, eyes, mouth, and respiratory tract) and cause rhinitis, conjunctivitis, and, in many cases, seasonal asthma. The intensity of the symptoms is usually correlated with atmospheric pollen concentrations, although each person has their own reaction threshold.
Most common symptoms of pollen allergy
Pollen allergy symptoms can range from very mild discomfort to conditions that significantly limit daily activity. Among the most common manifestations are:
- Allergic rhinitis: Sneezing fits, intense nasal itching, watery mucus, and nasal congestion. It is often accompanied by itching of the palate and ears.
- allergic conjunctivitis: Red eyes, intense itching, constant tearing, and a gritty or foreign body sensation in the eyes.
- Pollen asthma: Cough, shortness of breath, chest tightness, and wheezing. It usually appears during the same periods when the patient experiences rhinitis and conjunctivitis, although in some people it occurs in isolation.
In some cases, the reaction may be more widespread, with tiredness, headache, or worsening sleepespecially when nasal congestion is severe. Although severe reactions (such as anaphylaxis) are much less common with pollen than with other allergens, poorly controlled pollinosis can worsen pre-existing respiratory conditions, such as persistent asthma.
Diagnosis of pollinosis and the role of pollen counts
Pollen allergy is diagnosed by the specialist in AllergologyThis approach combines medical history with specific tests. It typically analyzes the relationship between symptoms and the time of year, exposure to certain plants or environments, and the response to medications such as antihistamines or inhaled or intranasal corticosteroids.
The skin tests Prick tests with extracts of suspected pollens are the basic tool for confirming sensitization. In some cases, they are complemented by blood tests for specific IgE, respiratory function tests (spirometry) if asthma is present, and controlled provocation tests (nasal, conjunctival, or bronchial) when more precise data are needed.
Los daily pollen counts Data published by networks such as the Spanish Aerobiology Network (REA) or the Aerobiology Committee of the SEAIC are very useful for correlating symptoms and exposure. These networks have sampling stations distributed throughout the country, and their data can be found in the media and on specialized websites such as www.polenes.com.
Knowing what pollen concentration usually triggers symptoms in each patient allows plan the treatment: when to start or increase preventive medication, when to take extra precautions, or when it is more prudent to avoid outdoor activities.
Treatment and measures to reduce pollen exposure
The approach to pollinosis is based on three pillars: avoid exposure as much as possibleUse appropriate medication and, in some cases, resort to specific immunotherapy (vaccines). None of these alone is usually sufficient in moderate or severe cases; ideally, they should be combined according to the specialist's instructions.
Among the main prevention measures recommended are:
- Keep them closed windows At night and during peak pollen times (early morning and evening), ventilating the house for a short time and preferably at midday.
- Use air conditioning with pollen filters at home and in the car, making sure they are renewed when appropriate.
- Avoid outings to the countryside or to areas with high vegetation density on days with peak pollen levels, especially if it is also windy or there is a forecast of storms with high electrical content.
- Traveling with the car windows rolled up and avoid traveling by motorbike or bicycle during peak pollination season.
- Do not tend clothes or sheets outdoorsbecause pollen is easily deposited on tissues.
- Shower and change your clothes when you get home to remove pollen stuck to hair, skin and clothing.
- Use Sunglasses and, if necessary, a face mask (preferably FFP2 or FFP3) on days of very high concentrations.
- Clean the dust with vacuum cleaner and damp cloths, instead of sweeping, so as not to stir up particles.
Regarding medication, the allergist may prescribe oral antihistaminesIntranasal corticosteroids, anti-allergy eye drops, bronchodilators, and other medications may be prescribed depending on the patient's individual needs. It is essential to follow the instructions regarding dosage and duration of treatment and to avoid self-medication, as some medications can cause drowsiness or other side effects that must be considered, for example, when driving.
La specific immunotherapy (The so-called "allergy shots") are reserved for patients in whom the responsible pollen is clearly identified and whose allergy significantly interferes with their daily lives despite standard measures. This treatment, always supervised by an allergist, aims to modify the immune response in the long term, reducing the intensity of symptoms and, in many cases, preventing the progression of rhinitis to asthma.
Practical tips for the daily life of pollen allergy sufferers
To better manage pollen allergies, it's advisable to incorporate a series of simple habits in the daily routine during the risk season:
- Consult the pollen levels on specialized websites (such as www.polenes.com or SEAIC) before planning outdoor activities.
- Avoid practicing outdoor sport between 5:00 and 10:00 in the morning and between 19:00 and 22:00, periods in which more pollen is usually concentrated.
- Take extra care on days with strong winds or thunderstorms, as they can increase the concentrations of respirable allergenic particles.
- Perform nasal washes with saline solutions or seawater Upon arriving home, to remove pollen from the nasal mucosa and improve breathing.
- Maintaining hygiene eyes and handsUse artificial tears if there is eye irritation and try not to rub your eyes, as this aggravates the inflammation.
- Avoid mowing the lawn or perform gardening tasks that stir up pollen on days of high pollination.
- Be especially careful with the fresh fruits and vegetables that may have pollen deposited on their surface, washing or peeling them before consuming them.
- Go to allergist If symptoms worsen or are not well controlled with the usual treatment, to assess adjustments in medication or the suitability of immunotherapy.
Count on clear and up-to-date information Knowing which pollens are prevalent in your area, how the season is progressing, and what resources are available to you makes a big difference. With a good diagnosis, appropriate treatment, and basic preventative measures, most people with hay fever can continue to lead a virtually normal life and even enjoy spring, despite the presence of pollen in the air.
