Brief Answer:
further evaluation needed

Detailed Answer:
Hello XXXXXXX Welcome back,
I've gone through your query and understand your concern for your wife,

Well, being allergic can certainly cause such persistent cough. However, since it's persisting despite taking the medications, further evaluation is needed to find out the root cause.

Allergy is a broad term, so it's necessary to find out the probable offending agent at first. For this, it's necessary to undergo a Comprehensive Allergy Panel Check-up to look into it further.

You haven't mentioned which specialty of doctor you've visited (visiting the specialist is important as they're expertized with the relevant branch). As in her scenario, ideally, she should be checked up by either a Pulmonologist/Chest Medicine specialist or an ENT specialist).

Is there any frequent exposure to dust/windy places?

Is she allergic to pollen/dust/any food particles?

Was there any history of childhood asthma?

Is there any history of fever/chronic headache/runny nose/sinus related concerns?

Please note that there are several reasons behind such persistent cough. So a proper clinical examination by the Pulmonologist/ENT specialist along with a few relevant investigations (CBC, Peripheral blood smear, ESR, Sputum for gram stain; AFB; Culture sensitivity examination, Chest X-ray, X-ray of the paranasal sinuses etc.) is necessary to find out the exact diagnosis. Treatment is mainly by treating the cause, so, I'd suggest getting further examined first in order to find the exact reason behind this.

Meanwhile, please continue all the medications as advised by the doctor, along with the gargles and steam inhalation. Since it's increasing at night, take steam inhalation once just before going to bed, avoid cold air exposure, drink lukewarm water.

Please let me know if there are any further queries...

Take Care
Kind Regards

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