Short answer: Sinusitis can usually be controlled very well, and many people stay symptom-free for long periods. Acute sinusitis often settles completely. Chronic sinusitis is managed rather than 'cured overnight', using sprays, rinses, treating allergies or a blocked nose, and surgery only when medicines are not enough.
Whether sinus problems settle for good depends on the cause. A one-off infection after a cold usually clears fully. Repeated or long-standing sinusitis is often driven by something underneath, such as a deviated septum, nasal polyps, swollen turbinates or allergy. When that underlying cause is found and treated, symptoms may reduce significantly. A nasal endoscopy in the clinic helps an ENT see what is blocking drainage. The aim is long-term control with the least treatment needed, so the honest answer is 'very manageable' rather than a promise of a permanent cure.
Dr. Prashanth's perspective
Sinus inflammation is something that can recur. Taking antihistamines daily can, in fact, cause more harm in the long term, because they reduce ciliary movement and so slow down mucus clearance. Saline washing definitely helps, which is why I usually give it to my patients after surgery, once I have improved the sinus drainage.
— Dr. Prashanth R. Reddy, ENT Surgeon, ENTHealth360
Related reading: Why does my sinus keep coming back every few months? · Will sinus come back after surgery?
General patient education. An individual consultation is needed to assess your symptoms and treatment options.

