Chapter 22
Food and Respiratory Allergies in South India: An Overview
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K. A. Vishak and R. C. Sahoo Department of Chest Medicine and Allergy, Kasturba Medical College Hospital, Mangalore-575001, Karnataka, India
Allergies especially food allergies are rarely documented in India even though they are highly prevalent. Insufficient clinical data is presently available regarding food allergies in south India and the allergen profile peculiar to Mangalore, a city in coastal India, has not been profiled so far.
The aim of this study was to estimate the incidence of food allergies in patients with rhino-bronchial allergy prevalent in Mangalore, a coastal city in south India.
Methods, Materials and Results The study was carried out in a tertiary medical college teaching hospital in Mangalore, located in coastal belt of south India. One hundred consecutive patients suffering from rhino-bronchial allergy (RBA) were included. Rhinobronchial allergy was confirmed by clinical evaluation, pulmonary function tests, chest radiographs, serum IgE estimation, and osteomeatal complex (OMC) computerized tomographic scans. All these patients were subjected to skin prick (SPT) which was done with standardized allergens as per standard recommendations. The skin tests kit included 86 different aeroallergens along with 26 common food allergens. The allergen categories were tree, weed, dust, insects, danders, food allergens, and miscellaneous allergens. © 2008 American Chemical Society
In Food Contaminants; Siantar, D., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2008.
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368 Among one hundred patients suffering from rhino-bronchial allergy, the incidence of food allergy was 41%. Allergy to a single tested food allergen was seen in 23%, while 18% showed allergies to multiple food allergens. The prevalence of food allergies were highest to egg (8%), milk (8%), and green gram (8%). The prevalence of other food allergies tested in decreasing orders of theirfrequencywere chick peas (6%), wheat (5%), pista (4%), black gram (4%), peanut (3%), mustard (3%), chocolate (3%), soya (3%), cashew nut (3%), walnut (2%), coffee (2%), banana (1%), and red gram (1%). The average total serum IgE was 1119.6 IU/mL in patients with RBA while in those with food allergies it was 1140 IU/mL and 1105 IU/mL in those with RBA without food allergies.
Discussion Allergy is a term often used 'to give a touch of mystification to ignorance'. This quote is specifically relevant to India, where allergy is highly prevalent although a grossly under-reported phenomenon. For the efficient diagnosis of the allergy and its effective treatment it is very important to know about the prevalence, seasonal and annual variations of aeroallergens, flora and fauna prevalent in the area, and the dietary profile characteristic of the local population. The chest & allergy clinic in the tertiary hospital in Mangalore is attended by a diverse mix of patients from both urban settings and a sizeable rural population from the satellite villages around the city. In today's urban Mangalore, allergies due to aeroallergens, indoor air pollution by microorganisms such as fungal spores causing sick building syndromes, and food allergies are frequently reported. As has been previously proved, dust mites are an important source of inhalant allergens particularly in the coastal areas of the country and Mangalore is no exception. Urbanization with its high levels of pollution is linked to high incidence of pollen, dust, and microbial spore induced respiratory allergies, as it enhances the airway responsiveness to aeroallergens. Rolling of tobacco in beedis is an important occupational hazard as allergy to tobacco leaf dust and fungal contamination of the tobacco leaves in the cramped workplaces lead to pulmonary symptoms. Food allergies often masquerade as other systemic diseases and often the symptoms are very subtle. The food allergy pattern of a country is influenced by the foods most commonly consumed. The dietary habits prevalent in Mangalore are quite diverse and are peculiar to this part of the world. In Mangalore, the majority of the population consumes a mixed diet made up of pulse (legumes), cereals, vegetables, and exotic sea foods, including fish. The prevalence of food allergies for a few tested allergens amongst patients with RBA was surprisingly high at 41%, with multiple allergens being implicated in 18% of these cases.
In Food Contaminants; Siantar, D., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2008.
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369 Allergy to cashew pollen (Anacardium occidentale) detected in 3% of RBA patients in this cashew growing belt often leads to asthma like symptoms (7). Also seen in this coastal belt with its strong inclination to seafoods are food allergies to shellfish, shrimp, oyster, and other exotic sea foods. We have been unable to document seafood allergies due to non-availability of standardized allergens. However quite a number of patients had historical and clinical evidence of seafood allergy. A higher incidence of other food allergies encountered in this population is also possibly linked to prior sensitization and cross reactivity to these seafood allergens. In contrast to many western countries, chickpea preparations are consumed in large quantities in this part of the world (2) and it is also reflected in our study which showed a high incidence of allergy to chickpeas. The predominant symptoms after chickpea ingestion were respiratory. Our study also showed moderate prevalence of allergy to wheat plant antigens (5%), with lesser prevalence of allergy to wheat threshing dust (WTD) and to wheat dust antigens, unlike studies reported in other parts of India which show lower incidence of allergies to wheat antigens (3). This interesting variation in clinical profile of allergy amongst the populace in this coastal city needs further validation by aerobiological studies. Also, the possible allergens need to be characterized biochemically and at a molecular epitope level for proper diagnosis and treatment of allergy. Further elaborate studies need to be done to characterize, diagnose, and treat food allergies.
References 1. Fernandes, L.; Mesquita, A. M . Anacardium occidentale (cashew) pollen allergy in patients with allergic bronchial asthma. J. Allergy Clin. Immunol. 1995, 95, 501-504. 2. Patil, S. P.; Niphadkar, P. V.; Bapat, M. M . Chickpea: a major food allergen in the Indian subcontinent and its clinical and immunochemical correlation. Ann. Allergy Asthma Immunol. 2001, 87, 140-145. 3. Lavasa, S.; Kumar, L.; Kaushal, S.C.; Ganguli, N . K. Wheat threshing dusta "new allergen" in April-May nasobronchial allergy. Indian Pediatr. 1996, 33, 566-570.
In Food Contaminants; Siantar, D., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2008.
