Allergy, sinusitis or reflux: how are they told apart?

Postnasal drip does not make a diagnosis by itself — the same symptom can be seen in allergic rhinitis, in sinusitis and in reflux. What distinguishes them is the character of the discharge and the accompanying findings:

In allergic rhinitis: the discharge is thin and watery, usually with sneezing and watery eyes. Patients mostly describe “a constant need to clear my throat” or a slight sensation of dripping.
In sinusitis: the discharge is thicker and stickier, with a feeling of fullness in the throat, a bad taste or smell and facial pain; there may also be fever.
In reflux: the sensation of drip is often accompanied by hoarseness, a need to clear the throat that is worse in the morning, and a sour or bitter taste in the mouth — classic heartburn is not always present.

An important point: the swelling of the lining in allergic rhinitis can impair sinus drainage and over time set the stage for sinusitis — so the three can sometimes overlap.

Which symptoms call for an ENT examination?

I recommend an assessment if symptoms last longer than 10 days, if they improved at first and then got worse again, if there is marked facial pain, if there is fever, or if the symptom is one-sided and severe. If you have any of these, I advise being examined rather than waiting for it to pass.

What is treatment based on?

The direction of treatment is set by the source of the discharge — so at the examination I look endoscopically at where it is coming from. Thin secretions seen at the front of the nose and on the turbinates are consistent with allergy, while thick secretions coming from the middle meatus or the sinus drainage pathways suggest sinusitis. Endoscopic examination is the gold standard for making this distinction.

Treatment differs according to the cause: if it is allergic, allergy treatment (antihistamine, nasal spray) comes first; if it is sinusitis, treatment directed at the sinuses; if it is reflux, reflux treatment. The approach of “I have postnasal drip, so start antibiotics” is not correct — most of the time imaging shows no sinusitis, and the wrong treatment is both ineffective and unnecessary.