A constant shallow cough is often referred to a smoker’s cough. This is due to the fact that smoke causes constant irritation in the airways. Some long term smokers will also suffer with airway disease such as chronic bronchitis where a persistent cough is one of the characteristic symptoms. However, there are various other causes of a persistent cough even in non-smokers. It is important not to ignore a symptom like coughing even if it is dry and shallow. It may not seem dangerous but could be a symptom of a serious underlying disease.
Initially the irritants in smoke inflames the airways and stimulates cough receptors. This causes a person to cough until the irritant is removed. Cigarette smokers tend to indulge several times in a day and shortly after the irritant is cleared, it is inhaled again. The cycle is ongoing unless a person stops smoking. It can also be due to secondary smoke which is why passive smokers may also have this smoker’s cough.
The other reason for the ongoing cough among cigarette smokers is post nasal drip where excessive secretions from the nasal cavity leaks into the back of the throat. Smoking worsens existing post nasal drip as well. Here it tickles the throat and elicits a shallow and abrupt cough. Long term cigarette smoking can cause permanent damage to the airways and even lungs. This is seen in chronic obstructive pulmonary diseases like chronic bronchitis and emphysema. A cough is more prominent in chronic bronchitis.
The main causes of coughing due to smoking is irritants in the airways, post nasal drip and chronic bronchitis as mentioned above. These conditions can also affect non-smokers. There are also other possible causes which may be seen in both smoker’s and non-smokers.
This is a commonly ignored cause of a cough but occurs when acid rises up as high as the throat. It irritates the throat and elicits coughing. Reflux is more likely to occur in the elderly and even though heartburn and other typical symptoms are absent, it needs to be investigated since it is very common.
Although the main respiratory symptom of asthma is wheezing, asthmatics also tend to suffer with mild coughing. This is present even when a person feels that they are able to breathe freely. Once the airways tighten up, the wheezing becomes more prominent than the cough.
Respiratory tract infections include the common cold, flu and acute bronchitis. Even after these conditions clear up there may be a persistent cough for days or weeks afterwards. It usually settles on its own over time.
Allergies to dust, pollen and spores causes excessive production of mucus in the nose. It is known as allergic rhinitis or commonly as hay fever. Patients also suffer with sensitivity to strong odors and smoke. The mucus can drip down into the back of the throat and irritate it – post nasal drip. The term post nasal drip is a broad term for irritation of the throat caused by the nasal mucus and includes hay fever.
Slowly progressing cardiac failure can cause “water” in the lungs over a long period of time. This affects the lung capacity and irritates the respiratory tissue. A persistent cough is therefore possible. This is a significant cause in the elderly who are more likely to be suffering with cardiac failure for a number of reasons.
Some drugs may also cause constant coughing as a side effect. This is mainly medication such as ACE inhibitors used in the treatment for high blood pressure. ACE inhibitors are widely used by the elderly who are more likely to suffer with hypertension. Other drugs may also be responsible but none as are as major a contributing factor as ACE inhibitors.
The main infection that causes prolonged coughing is tuberculosis (TB). Other TB symptoms like weight loss and coughing up blood (hemoptysis) may not be identifiable in the early stages. Weight loss and night sweats along with the coughing should raise the concern about TB. It is more likely to occur in the elderly who have lower immune defenses.
Tumors in the throat, airways and lungs can also cause coughing. Generalized symptoms like weight loss and fatigue may be the only other noticeable symptom in the early stages. A tumor should not be suspected immediately without doing further tests to confirm its presence.
Various other conditions can also cause chronic coughing although it does not involve the lung directly. This includes diseases such as chronic tonsillitis, tonsil stones and enlarged thyroid gland.