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PAPERS: Mahmoud Zureik, Catherine Neukirch, Bénédicte Leynaert, Renata Liard, Jean Bousquet, and Françoise Neukirch Sensitisation to airborne moulds and severity of asthma: cross sectional study from European Community respiratory health survey BMJ 2002; 325: 411 [Abstract] [Full text]

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Sensitisation to airborne moulds and severity of asthma

Michael J. Abramson, Shyamali Dharmage, Frank Thien and E.Haydn Walters   (29 August 2002)

ACUTE SEVERE ASTHMA – DIFFERENT RISK FACTORS IN DEVLOPING COUNTRIES

Dr. J.K. Samaria   (9 September 2002)

Sensitisation to airborne moulds and severity of asthma 29 August 2002
Michael J. Abramson, Associate Professor of Epidemiology & Preventive Medicine Monash University, Melbourne, Australia 3004, Shyamali Dharmage, Frank Thien and E.Haydn Walters Send response to journal: Re: Sensitisation to airborne moulds and severity of asthma	The cross-sectional analysis of international data from the European Community Respiratory Health Survey (ECRHS) by Zureik and colleagues[1] is a timely reminder of the importance of fungi in severe asthma. However this is not the first time that an association between fungal sensitisation and asthma has been noted in our part of the world. In an analysis of ECRHS data from Melbourne, we found that sensitisation to the mould Cladosporium was the strongest risk factor for current asthma in young adults[2]. Unfortunately the number of sensitised subjects was small and it was not feasible to examine asthma severity. Furthermore in the inland towns of Moree and Narrabri, sensitisation to Alternaria was a stronger risk factor than sensitisation to Dermatophagoides pteronyssinus for childhood asthma[3]. Further insights are provided by studies that have directly measured fungal exposure. In a cross sectional study with our ECRHS cohort of 485 young adults, we observed an association between high fungal exposures and increased bronchial reactivity[4]. As this association could have been confounded by the season, we subsequently conducted a one year longitudinal study of asthmatics allergic to fungi. Mouldy houses were associated with increased peak flow variability, which confirmed our previous findings on the relevance of fungal exposure in severe asthma[5]. In our cross sectional study, we also observed an association between high cumulative fungal exposure and sensitisation to fungi. This finding suggested that sensitisation was an intermediate step in the biological pathway between fungal exposure over time and severe asthma. However there is now also increasing interest in the non-specific stimulation of 'allergic-type' asthmatic airway inflammation by non-allergenic biological adjuvants such as endotoxin and fungal products. It is of concern that the prevalence of severe asthma among young adults appears higher in Australia and New Zealand than in Europe or North America. This is similar to the pattern observed in children by the ISAAC study. The analysis by Zureik et al[1] would suggest that sensitisation to moulds and dust mites may explain some of the more severe asthma in our region. However it is difficult to infer causation from cross-sectional data and other environmental factors that may co-exist with allergens are undoubtedly also involved. Hopefully longitudinal analysis of data already collected or currently being collected for ECRHSII will shed further light on these issues. References 1.Zureik M, Neukirch C, Leynaert B, Liard R, Bousquet J, Neukirch F. Sensitisation to airborne moulds and severity of asthma: cross sectional study from European Community respiratory health survey. BMJ 2002;325(7361):411-. 2.Abramson M, Kutin J, Raven J, Lanigan A, Czarny D, Walters EH. Risk factors for Asthma among young adults in Melbourne, Australia. Respirology 1996;1:291-97. 3.Peat JK, Tovey E, Mellis CM, Leeder SR, Woolcock AJ. Importance of house dust mite and Alternaria allergens in childhood asthma: an epidemiological study in two climatic regions of Australia. Clin Exp Allergy 1993;23:812- 19. 4.Dharmage S, Bailey M, Raven J et al. Current Indoor Allergen Levels of Fungi and Cats, But Not House Dust Mites, Influence Allergy and Asthma in Adults with High Dust Mite Exposure. Am J Respir Crit Care Med 2001;164:65 -71. 5.Dharmage SC, Bailey M, Raven J et al. Mouldy houses influence symptoms of asthma among atopic individuals. Clin Exp Allergy 2002;32(5):714-20.
ACUTE SEVERE ASTHMA – DIFFERENT RISK FACTORS IN DEVLOPING COUNTRIES 9 September 2002
Dr. J.K. Samaria, Counsultant Chest Physician Deptt. Chest Diseases,Institute of Medical Sciences,Banaras Hindu University,Varanasi-5.INDIA Send response to journal: Re: ACUTE SEVERE ASTHMA – DIFFERENT RISK FACTORS IN DEVLOPING COUNTRIES	Acute severe asthma remains an important medical emergency with a risk of respiratory arrest and death. It requires prompt clinical assessment with aggressive medical management. Acute severe asthma is the most common presentation of life threatening asthma in which more than 70% patients are to be kept on mechanical ventilation. Most patients with severe acute asthma sit or stand with shoulder muscles braced, in an attempt to assist their breathing. Ill patients are usually pale and sweaty. Obvious cyanosis indicates severe hypoxaemia. Confusion and drowsiness only accompanies gross hypoxaemia and hypercapnia. Respiratory acidosis should be regarded as evidence of impending death. On auscultation, it is not uncommon to find bilateral silent chest. Measurement of heart rate and degree of pulses paradoxus are invaluable in initial assessment and subsequent monitoring of response to the treatment. Episodes of acute bronchial asthma may be observed during the changing season and weather conditions. Outbreaks of asthma were associated with thunderstorms. Some fungi depend on weather conditions for spore release (e.g. Didymella); hence fungal aeroallergens may cause epidemics of clinical asthma, similar to those seen in countries that experience ragweed seasons. The effects of weather changes on asthma are probably largely related to the indirect effects on local allergens, e.g. fungal spores, pollens or house-dust mite populations, rather than to direct cold or irritant effects on the airways. Tropical countries viz. India, mould and house dust mite are less important risk factor for acute bronchial asthma as most of houses both in cities or rural areas are well ventilated and less use of air- conditioning. In country like India, the most important cause of acute severe bronchial asthma is uncontrolled respiratory tract infections, inadequate or maltreatment of bronchial asthma due to high percentage of illiteracy.