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Asthma Articles and Research Abstracts

	ASTHMA & COUGHING
	CIGARETTES AND COUGH A cigarette can modestly alleviate morning cough! (As well as providing a small degree of bronchodilation). It is important for health professionals to recognise this, and not to deny the likelihood that whilst attempting smoking cessation, cough will often be worse. Forty-four healthy smokers in the UK were enlisted in a double-blind, crossover study to determine any effect of a 400 mcg inhalation of Ventolin™, compared with placebo, immediately before the first cigarette of the day. (Ventolin being considered to have some cough-suppressant action) [1]. Cough frequency was recorded for 20 minutes before Ventolin or placebo/lighting up, and for 60 minutes afterwards. The result was rather annoying. Smoking a cigarette significantly reduced cough frequency for those on placebo, down from 0.3 to 0.2/minute, whereas the slighter reduction with Ventolin (0.23–0.19/minute), was not significant. Whilst slowly undermining health, with many other effects besides provoking lung cancer and emphysema, smoking can produce an immediate reduction in smoker's cough, adding to the problems of smoking cessation. Ventolin did come into its own when cough was provoked after 60 minutes; compared with inhaled placebo, a 31% greater concentration of inhaled citric acid was required to provoke cough after inhalation of Ventolin. The authors wonder whether a different, perhaps long-acting, reliever, might be more effective than a cigarette for relief of smokers' morning cough.   ATOPIC COUGH Atopic cough (allergy-based), and cough-variant asthma (c-var-a), are relatively common causes of chronic, unproductive cough in Japan, where gastro-oesophagoeal reflux and post-nasal drip, common in Western countries, are rare. A recent Japanese study [2] compared atopic cough with c-var-a, and found that 79 subjects with atopic cough did not proceed to typical asthma within 4-5 years, in contrast to subjects with c-var-a, of whom 6 out of 20, untreated, did develop asthma within 3-4 years . (Of interest too, only 2 out of 35 with c-var-a who received Becotide proceeded to typical asthma, suggesting a worth-while protective effect in this condition). The authors point out that raised levels of eosinophils (allergy indicators), are in atopic cough only found in the larger airways, and in induced sputum samples, but not in broncho-alveolar lavage fluid, (which samples small airways) as in atopic asthma. Further distinctions are the absence of ‘twitchy airways’ (increased BHR, lower threshold for bronchiole contractility), which is different from the low threshold for cough; and the absence of response to reliever drugs which are helpful in c–var-a. On the other hand, both conditions respond to inhaled steroids, so that one wonders whether both conditions, observed for much longer untreated, would develop typical asthma. It would seem worth while, for patients with atopy and unproductive cough, to try a month on a low dose of an inhaled steroid when other causes have been excluded. Cough sensitivity has been explored in another Japanese study [3]. The authors point out that although sensitivity is increased during attacks of asthma (and lung infections), it is not, (in patients with allergic asthma whose main symptoms are wheezing and breathlessness but not cough), related to airway calibre, “twitchy airways”, or eosinophilic inflammation. References: [1] Thorax 2002;57 Suppl iii::24 [2] Ibid 2003;58:14-18 [3] Ibid: 9-22
	(Published in Open Airways - Journal of the Wanganui Asthma Society Inc. Abstracts and comment by Dr Kenneth Thomson)

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