The purpose of this study was to investigate if iron deficiency has a role in unexplained chronic cough by contributing to irritability of the larynx.
Twenty-two non-smoking women with chronic unexplained cough and iron deficiency (a serum ferritin below 15 ng/ml) were examined initially, and then again after 2 months of treatment with an anti-histamine and proton pump inhibitor. After assurance that their cough would not respond to those two treatments, and they had normal lung function tests, no respiratory infections and no relevant systemic disease, women with a ferritin less than 15 ng/ml were given iron supplementation for 2 months in the form of iron sulphate tablets daily of 330 mg-660 mg.
The cough dramatically improved in all of the patients after iron supplementation.
Commentary:
Chronic cough is a common condition with known and easy to diagnose causes and successful treatments the majority of the time. However, in up to 20% of patients, the cough remains unexplained or does not improve to targeted treatments. Cough is much more frequent and severe in women than in men, although the reason for this is unknown. One line of reasoning though is the different hormonal environment in men and women, and the other line of reasoning is a decrease in iron stores that differentiate adult women from adult men and pubertal girls. Nearly 20% of childbearing women have iron deficiency, because of menstruation and pregnancies. While we do not yet know how iron deficiency may be related to chronic cough, there is a reduced epithelial tongue thickness in those with iron deficiency, suggesting that the cough could be a result of increased mucosal surface permeability of irritants.
It is also suggested that since in children, gender does not influence cough, but perhaps puberty does. Researchers theorize that because asthma becomes more prevalent in girls than in boys after puberty, perhaps this is also true of chronic coughs.
This study offers a welcome new insight into chronic cough in women with one more reason to test ferritin levels; when ferritin levels are < 15 ng/ml in women with chronic unexplained cough, a simple experiment of iron supplementation is a welcomed safe treatment.
Reference
Bucca C, Culla B, Burssino L, et al. Effect of iron supplementation in women with chronic cough and iron deficiency. Int J Clin Pract 2012;66(11): 1095-1100.
