Can a Sinus Drainage cause Cough?

A chronic non-productive cough with history of nasal congestion might intuitively indicate a respiratory problem. However, it could well be something as uncomplicated as a 'post-nasal drip'. Let's understand how a sinus drainage causes chronic cough.
The most common diagnosis associated with signs of cough and trickle behind the throat is sinusitis. Here's the why and what about it. A respiratory infection causes excessive secretion of mucus on the inner membranes of nasal mucosa. This accumulated mucus tends to aggravate the mechanism of sinus drainage. The slow and constant nasal trickle caused by draining sinuses causes symptoms like sore throat and coughing.
Sinuses and their Function
Sinuses are present in four pairs; and are located on the forehead, cheekbones and nasal area. Frontal sinuses are positioned in the forehead region, maxillary sinuses behind the cheekbone, ethmoid sinuses are located between the nose and eyes; while the sphenoid sinuses are positioned deep in the skull bone.
Sinuses are small cavities in the skull bones that are air-filled and its main functions are voice resonance and mucus secretion. These air-filled cavities tend to make the bones of the skull lighter and aid the process of sound resonance.
The membranes lining the sinuses secrete mucus and are connected to the nasal passage via hair-like projections called nasal ostia. The mucus acts as a nasal lubricant and is necessary to avoid dust, pollutants and other harmful organisms from causing infection in the respiratory tract.
Why does Sinus Drainage Make You Cough?
A healthy sinus secretes watery mucus that is carried to the pharynx (in throat region) and later into the stomach. This physiological activity being involuntary normally stays unnoticed. However, individuals with nasal congestion or any other infection of the upper respiratory tract show symptoms of increased sinus drainage. This means that it interferes with the normal functioning of the nose, and mucus gets stuffed within the sinuses.
Also, because of the gravitational force, the sinuses keep draining the accumulated mucus into the throat. The nasal drip thus causes irritation to the larynx, pharynx, trachea and lungs. This results in symptoms like sore throat, dyspnea, cough which is again an involuntary reaction to protect the airways. If the infection is left untreated, the membranes may become inflamed further leading to pus accumulation.
Treating Sinus Drainage
Many people tend to brush aside symptoms of cough caused by sinusitis assuming it would heal on its own. However, you need to attend to it immediately since chronic cough may later cause unnecessary respiratory complications. An ENT specialist or a physician would first have to confirm the cause of cough whether it's a sinus problem or any other condition of the lower respiratory tract; and then treat it accordingly.
Treating the underlying condition like an allergy, sinusitis, rhinitis that has caused inflammation of nasal passage should help cure the cough. Home remedies like steam inhalation and hot drinks like tea or soups could reduce the discomfort caused by draining sinuses. Adequate water intake is recommended for proper hydration since this reduces the possibility of thickened mucus. The initial choice of drugs would be antihistamines, decongestants, nasal sprays and antibiotics. The physician would suggest a nasal wash, steroid sprays or surgical intervention depending upon the severity and duration of infection.