الفهرس 
EpidemiologyOnly 14 pages are availabe for public view
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Abstract
Allergies are increasing dramatically worldwide. Approximately 10% to 30% of the world’s adult population and up to 40% of children are affected by some form of allergy. Few studies evaluated asthma prevalence in Egypt, Ranged from 4.8 % to 9.1%.
There is a strong epidemiologic association between rhinitis and asthma when both relate to inhalant allergy, a finding that represent the pathophysiologic link between these two disorders so the concept ‘‘one airway, one disease’’ has been labeled accordingly.
Aeroallergens are relatively large and complex particles, such as pollens, moulds, insect parts, animal dander, plant fragments, and house dust mites that are capable of eliciting allergic reactions in susceptible persons. Fungi are eukaryotic, unicellular or multicellular. They are mostly spore-bearing organisms that exist as saprophytes or parasites of animals and plants. The fungi constitute a very large and diverse set of organisms, and the taxonomy is complicated. Classification schemes have undergone numerous revisions to develop a system easier to follow. Most fungi produce sexual and asexual spores and the taxonomy is based on that spore characteristics.
The role of fungi in producing allergic and respiratory symptoms is well established and has been described since the early 1700s. Of these aeroallergens Indoor moulds are most problematic in homes with high humidity, standing water, or water damage and in outdoor high dose exposures. Aspergillus, Cladosporium, Alternaria, Curvularia and Fusarium species have been reported as the most prevalent fungi of indoor and outdoor fungi around the world.
The major taxonomic groups of fungi that are currently recognized are the ascomycetes, basidiomycetes, and zygomycetes. Some authors also refer to a separate group, the deuteromycete that contains a large number of allergenic fungi that reproduce asexually by the differentiation of specialized hyphae called conidiophores. Among these, about 80 mould genera have been shown to induce type I allergies in atopic individuals. The most important allergenic fungi belong to the genera Alternaria, Aspergillus and Cladosporium, whereas members of the genera Candida, Penicillium, Clavularia and others seem to be less important as allergenic sources.
Fungi can cause problems to the lung either by acting as aeroallergens or by acting as a pathogen causing infection or even both mechanisms. Fungal allergic burden to human is broad and still need much clarification about diagnostic criteria to diagnose each such as Allergic bronchopulmonary aspergillosis (ABPA) , severe asthma with fungal sensitization (SAFS) and Allergic fungal sinusitis (AFS)
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Many studies in past decades showed that severity of respiratory allergic disease is correlated with fungal sensitivities. These studies began early in the 1870s by charles Blackley with inhaling fungi from straw bristle mould Chaetomium elatum and Penicillium glaucum. Many studies later stated that sensitization to Alternaria or Cladosporium is a powerful risk factor for severe asthma in several European countries. Asthma deaths, multiple hospital admissions, respiratory symptoms and peak expiratory flow rates can be adversely affected by high fungal spore dose in outdoor air. Although it is reasonable to expect that exposure to fungi in sensitized individuals with asthma is likely to lead to symptoms, it is less clear that exposure to fungi is likely to increase the risk of developing asthma.
The aim of present study is to evaluate the prevalence of sensitization to various species of mould and yeast allergens among other common aeroallergens in Egyptian patients with respiratory allergy.
The present study included 200 patients diagnosed with bronchial asthma and/or allergic rhinitis. For each patient, the following had been done: Detailed allergic history and clinical examination with assessment of asthma control level, allergic rhinitis severity, Spirometry and SPT to aeroallergens using commercial standardized extracts. Extracts for skin testing included standardized extracts of 10 fungal allergen extract in addition to other 6 aeroallergens, positive and negative controls
Mean age of the patients was 32.2 ± 14.4 years with a range from 6 -70 years old. Females represented 65% of the study population while males represented 35 %. Of studied patients, 14 % were aged between 6-14 years; 66 % had age range from 15-44 years and 20% were aged between 45 and 70 years. Asthma represented 40% of the study population while allergic rhinitis represented 47% and combined allergic bronchial asthma with allergic rhinitis represented 13 %.
The results of skin prick test to all studied patients revealed that 74 % had positive results to at least one allergen extract and only 26 % had negative skin prick test. As regards patients with positive skin prick test to at least one allergen extract, positivity towards fungus extract was 41.9 % and positivity towards other allergen was 58.1 %.
Regarding the severity degree of allergic rhinitis, there were 28.3 % of studied allergic rhinitis patients had mild degree and 71.7 % patients had moderate to severe allergic rhinitis. Regarding the control state of bronchial asthma, there were 26 out of 106 patients (24.5 %) were well controlled, whereas, 62 out of 106 patients (58.5 %) were partially controlled and 18 out of 106 patients (17 %) were poorly controlled.
When comparing the incidence of skin prick test results between various age groups, the study showed 14 % of 6 years to 14 years; showed positive results towards fungal extract in 42.9%. Out of 132 patients who had age of 15 to 44 years, 30.3% of them had positive results towards fungal extracts and out of 40 patients who
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had age range of 45 to 70 years, 25% of them had positive results for fungal extracts. Percentage of fungal sensitivity among age group who had aged from 6 years to 14 years was higher than percentage of fungal sensitivity among other age groups
Regarding results of skin prick test to common fungal extracts in the studied positive fungal population, Alternaria alternate represents 32.2%, Pencillium mix respresents 32.2% followed by Aspergellus mix and Chaetomium globosum each accounting for 22.6% of positive fungal sensitivity patients, then in 5th order was Mucor racemosus accounting for 19.4%. Regarding the results of skin prick test to common non fungal allergen extracts in the studied positive skin prick test study population, the study showed that dust mites extracts with its two species Dermatophagoides farina and Dermatophagoides pteronyssinus sensitivity represent the highest prevelence of allergen extracts senstivity. In patients with combined allergic rhinitis and allergic bronchial asthma, the results showed significant sensitivities to Pullularia pulluans, Merulium lacrymans and Chenopodiaceae weed mixtures.
Studies of fungal ecological systems found that Aspergillus and Pencillium are usually considered the major indoor fungi. Alternaria alternate has been reported in house dust samples in absence of environmental mould spores and so it can represent outdoor and indoor mould exposure. Egyptian ecological studies about fungal exposures found that, fungi concentrations were significantly higher on working weekdays than weekends. Although highest prevalence of fungal sensitivities among respiratory allergic patients in our research was in category of mostly indoor fungi, these fungi could also be found in outdoor environment.
Many studies tried to answer questions of fungal species prevalence in respiratory allergic patients with skin prick tests or even sputum cultures. These studies denoted that Aspergillus, Alternaria, Cladosporium and Pencillium were the most identified fungal allergen
When studying the relation of the level of asthma control and the number of positive fungal sensitivity, The results showed that highest percentage (19.2%) of patients in well controlled category were sensitized to only one of studied fungal extracts, whereas, the highest percentage (11.1%) of patients in poorly controlled category were sensitized to 3 of studied fungal extracts. With a significant P value 0.02, it can be said that the number of fungal species extract sensitivities was related with level of asthma control.