Cough is your body's reflex to expel a large column air from your lungs to clear your airway from mucous, foreign bodies and irritants. However, when it is excessive, it is likely a symptom of an underlying conditoon. There are many potential reasons for a dry cough but the two most common cause seen in my practice would be:
1. Postnasal drip - this refers to excessive or thick mucous flowing down from the back of your nose to your throat. The mucoud from the nose can irritate your voice box, resulting in an irritative cough. The two most common cause of postnasal drip are Rhinitis (sensitive nose) and Sinusitis (infection of the sinuses). Patients with Rhinitis usually experience frequent blocked nose, clear runny nose, sneezing, postnasal drip, itchy nose and eyes and watery eyes. Rhinitis is treated with allergen or trigger avoidance, nasal steroid sprays and anti-histamines.
On the other hand, patient with sinusitis will experience blocked nose, facial congestion or pain, coloured mucous (yellow, brown, green or blood-stained) and reduced or loss of sense of smell. Sinusitis is usually treated with a course of antibiotics, saline nose wash and nasal steroid sprays.
2. Laryngopharygeal reflux (LPR) - this is a condition in which acid contents from the stomach back flows up to the level of the voicebox in the throat. The voicebox is a very sensitive organ that can be easily inflamed from acid contents from the stomach. An inflamed (swollened) voice box can result in a feeling of something stuck in the throat (globus pharyngeus), sore throat, cough, hoarse voice and frequent throat clearing. Treatment of LPR include lifestyle modifications (e.g. taking small meals, avoid eating or drinking 3-4 hours before sleeping, avoiding acid reflux causing food such as deep fried food, spicy food, chocolates, caffeine and alcohol). From the clinical history that you provided, if you do not have any nasal symptoms, this may be the reason for your persistent cough.
Of course there are many other causes of a prolonged cough such as side effects of medications (e.g. ACE-inhibitors used for blood pressure control), cigarette smoking and lung conditions (e.g Asthma and Bronchitis). If your cough is prolonged, I would suggest that you visit a General Practitioner (GP) first. If necessary, a chest X ray or a referral to an ENT Specialsit or Lung Specialist may be needed, depending on the GP's suspicion of the likely cause based on clinical history and physical examination.
Hope this helps and all the best!
