## 5 Discussion  
Nationwide, 79.3% of patients diagnosed with conjunctivitis and rhinitis (rhinoconjunctivitis) have an allergic cause well above the frequency of other causes. Conjunctivitis is considered intermittent when symptoms occur four days or fewer per week or for four consecutive weeks or fewer. Persistent forms occur more than four days per week and for more than four consecutive weeks. According to these criteria, 50.6% of patients suffer from intermittent conjunctivitis and 48.8% from persistent conjunctivitis (in the case of rhinitis, it is 34% and 66%, respectively, for intermittent and persistent rhinitis). In addition, 50% suffer from mild allergic conjunctivitis, 47% moderate, and 1.6% severe (annoying signs and symptoms, impact on vision, interference with academic or work tasks, and impairment in daily activities, reading, and/or sports are considered to assess the severity of the disease) [25]. In recent decades, there have been significant increases in allergic rhinitis, especially in Western countries. In international epidemiological studies, such as that carried out in 1994 in children in 54 countries by the ISAAC (International Study of Asthma and Allergies in Childhood), very variable prevalence figures were recorded (1.4-39.7% in children aged 13 to 14 years, and 0.8-14.9% in children aged 6 to 7 years), while in Spain there were intermediate values: between 11.7% and 21.8%. In adults, it is around 25% in Western Europe in the general population and 21.5% in Spain [25; 26; 27; 28]. Some 52.5% of patients who visit allergy clinics in Spain for the first time (with the main reason being nasal symptoms -89.4%-, followed by eye discomfort -56.5%-, and, less frequently, cough -26.9%-, dyspnea -26.9%-, and chest noises -10.9%-) are diagnosed with rhinoconjunctivitis, compared to 21% in the case of asthma, which is the second cause of visits to the allergy specialist. In addition, 17.5% of patients consult for both diseases at the same time. People with rhinoconjunctivitis mostly come from urban environments (65.1% of the cases)--some 24.3% live in semi-urban areas and 10.3% in rural areas. Of the patients, 62.7% have a family history of atopy, specifically rhinitis at 46.7% of cases, asthma in 28.1%, and conjunctivitis in 17.8%. This is followed by drug allergy (6.3%), atopic eczema (5.4%), food allergy (4.9%), Hypenoptera allergy (0.7%), and others (3.15%) [25]. In the CAM, 12.4% of these patients are sensitized to mites, 27.5% to animal epithelia, and 7.9% to fungal spores. More specifically, the types of pollen to which patients with rhinoconjunctivitis show a sensitization reaction are _Gramineae_, 87.1%; followed by _Olea_, with 58.9%; _Cupressaceae_, with 40.5%; and _Platanus_, with 23.9%, among the most prominent. Sixty-six percent of patients seen for the first time in allergology clinics in Spain for allergic rhinitis are of the persistent type (symptoms occurring more than four days per week and for more than four consecutive weeks), compared to 34% of the intermittent type. In addition, 29.9% suffer from mild allergic rhinitis, 59.7% from moderate, and 8.7% from severe allergic rhinitis [25]. Although some epidemiological studies have questioned that the trend of increasing prevalence of allergic pathologies in the last three decades may be due to an increase in the concentration of pollutants in the atmosphere, several botanical studies affirm that there is an increase in the expression of allergenic proteins in several types of pollen grains, as a consequence of the joint effect of atmospheric pollutants and changes in weather patterns [12]. This fact could indicate, as suggested by different researchers, the need to study the concentrations of pollen allergens and these pollutants to perform an epidemiological evaluation of the environmental determinants of respiratory allergies.