[Skin sensitization to pollens in Morocco. Multicenter study]

The objective of this study was to determine the prevalence of skin sensitization to certain pollens in some regions of Morocco. This multicentric study involving 10 centres included a consecutive series of 640 patients consulting for the first time between february and april 1998 for asthma and/or rhinitis and/or conjunctivitis. Skin prick tests (SPT) were performed with stallerpointes (Stallergenes) and interpreted according to standard procedures. Pollinosis was ascertained when SPT was positive to one or more pollens. Epi-Info was used to analyze the data. SPT were positive in 75.9% and prevalence of sensitization to pollens was equal to 28% (179 cases). It ranked second after house dust mites (63%), olive, 5 grass, cupressus, parietaria and corylus sensitization were encountered in 19.8%, 10.9%, 3.8%, 1.7% and 1.3% respectively. Prevalence of sensitization to pollens didn't vary significatively according to age: 25.4% in females versus 31.1% in males (p = 0.13). Prevalence of pollen sensitization was 26.6% in case of asthma versus 30.9% in non asthmatics patients (p = 0.30), 30.1% in case of rhinitis versus 16.9% in non rhinitics (p = 0.009), 36.4% in case of conjunctivitis versus 22.7% in case without conjunctivitis (p < 0.0002). According to the regions, prevalence was significatively high in areas like Meknes (56%), Beni-Mellal (48.1%), Marrakech (43.5%) where olive is abundant in comparison with Oujda (30.8%), Agadir (30.8%), Tanger (27.3%), Rabat (21.8%), Safi (21.3%), Casablanca (11.6%) and El Jadida (10%). The prevalence was up to 84.3% when symptoms were predominant in spring versus 16.8% in other seasons (p < 0.0001). Thus, although SPT did not include numerous other pollens, olive pollinosis seems to be prevalent in Morocco, followed by allergy to grass pollen. Such studies need to be carried out in line with pollen count.