The Etiologies, Pathophysiology, and Alternative/Complementary Treatment of Asthma

Alternative Medicine Review, Feb, 2001 by Alan L. Miller

Gastrointestinal symptoms occur more frequently in children with asthma and atopic dermatitis;[47] and abnormal gastrointestinal permeability is found in a greater percentage of asthmatics compared to non-asthmatic controls.[48] It is possible there is a common defect in the respiratory and gastrointestinal mucosa, either caused by the asthma or as a possible cause of asthma. Increased gastrointestinal permeability can allow large antigenic molecules to be absorbed through the mucosa, causing sensitization to foods. Possibly the increased permeability in the lungs caused by dust mite antigen causes a similar increase in transfer of antigenic material across the respiratory epithelium.[27]

Although the role of food allergies as a causative factor in asthma remains ambiguous, it seems some individuals do benefit from avoidance of identified problem foods. This option should not be overlooked in dealing with asthma.

Yeast/Fungi

Fungi are known to be causative factors that induce asthmatic symptoms. Outdoor airborne fungi, including Cladosporium, Alternaria, Penicillium, and Aspergillus are significant triggers of IgE formation, as are the indoor fungi Aspergillus, Neurospora, and Eurotium. In addition, some practitioners believe there is a strong fungal/yeast component in the lung and/or gut microflora in individuals with asthma.[31,49,50] Ridding the home or work environment of these organisms and utilizing antifungal treatments as appropriate has been reported to improve asthma symptomatology.

Subjective symptoms and peak expiratory flow (PEF) in 74 children with asthma were followed for 16 weeks, and correlated with the amount of bacterial endotoxin and fungal 1,3-beta glucan levels present in house dust. After adjusting for pet presence, type of floor cover, and dust mite allergen levels, yeast levels were positively correlated with PEF variability in these children.[51]

Sensitivity to fungal allergens has also been found to be a risk factor for severe life-threatening asthma. A New Zealand study of patients admitted to a hospital intensive care unit (ICU) revealed that patients admitted to the ICU had a significantly greater incidence of reactivity to Alternaria tenuis, Cladosporium cladosporoides, Helminthosporium maydis, or Epicoccum nigrum (54% vs 30% for other groups not admitted to the ICU or not hospitalized for asthma).[52]

Fungal cultures were performed from bronchial secretions of 13 asthma patients and from the skin of 91 patients with atopic dermatitis. The predominant yeast species present on the skin were Candida and Rhodotorula species, while Candida species were the most prominent species isolated from bronchial secretions.[53] Candida albicans may well be a prominent allergen for people with asthma. The cell wall constituent, mannan, and acid protease -- an enzyme secreted by C. albicans -- are both highly allergenic, and serum IgE antibodies are often increased in atopic individuals.[54,55]

Animal and in vitro studies suggest if there is an imbalanced Th1/Th2 ratio of immune activity, Candida infection is more likely to Occur.[56-60] There has been little investigation to date as to whether asthmatics are more likely to have Candida infections because of Th2-dominance, or whether Candida infection predisposes an individual to experience asthma symptoms. What data there is suggests both may be true.[49,50,61,62] Regardless, these data suggest that environmental fungi and/or colonization with Candida or other organisms probably contribute to asthma severity. Environmental eradication of fungi, as well as internal antifungal agents, should be considered in those testing positive for reactivity to these organisms.