What is the difference between a cold and a sinus infection?

Short answer: A cold usually improves within 7 to 10 days. A sinus infection is more likely if symptoms last beyond 10 days, worsen again after initially improving, or come with facial pain, thick coloured mucus and fever. Most colds need only rest, fluids and saline, while persistent or severe symptoms deserve a doctor's review.

Key takeaways

• Timing is the most useful clue: colds peak early and settle within about 10 days.
• "Double worsening", improving then getting worse again, suggests sinusitis.
• Facial pain over the cheeks or forehead points more towards the sinuses.
• Antibiotics do not help a viral cold and are needed only in selected sinus infections.

Dr. Prashanth's perspective

A common cold usually settles on its own within a few days, so home remedies such as steam inhalation and saline gargles help. When the cold lasts beyond a week, there is a chance it has become a sinus infection, and an ENT evaluation is important. After that, the doctor can advise antibiotics or other medicines for relief as needed.

— Dr. Prashanth R. Reddy, ENT Surgeon, ENTHealth360

What is the difference between a cold and sinusitis?

A cold is a viral infection of the nose and throat, while sinusitis is inflammation of the lining of the sinuses.

Many different viruses cause colds. They irritate the nasal lining, causing a runny nose, sneezing and a sore throat.

Sinusitis often begins as a cold. The swollen lining blocks the small openings through which the sinuses drain. Mucus collects in these air spaces, pressure builds, and the trapped mucus can become a home for bacteria. Most sinusitis is still viral, but a smaller number of cases become bacterial.

How can you tell them apart?

Look at how long symptoms last, how they change over time, and where you feel discomfort.

More typical of a cold:

• Starts with a scratchy throat, sneezing and a runny nose.
• Peaks around day two or three.
• Gradually improves and largely clears within 7 to 10 days.

More typical of sinusitis:

• Symptoms lasting more than 10 days without improving.
• "Double worsening": you start feeling better, then get worse again.
• Pain or pressure over the cheeks, around the eyes or across the forehead, often heavier when bending forward.
• Thick yellow or green discharge, post-nasal drip and reduced smell.
• Sometimes fever, upper tooth ache or bad breath.

Mucus colour alone is not a reliable guide. Yellow or green mucus can occur in an ordinary cold too.

What can you do at home?

For a cold and for mild early sinusitis, supportive care is usually enough.

• Rest and fluids help your body clear the infection.
• Saline rinses or sprays once or twice a day clear mucus and keep the lining moist. Use boiled-and-cooled, distilled or sterile water for rinses.
• Steam inhalation for five to ten minutes can loosen mucus. Take care to avoid burns.
• Short-term decongestant sprays, for no more than three to five days, can ease blockage.
• Do not self-start antibiotics from an old prescription.

In Bangalore, the monsoon months and sudden weather changes often bring a wave of colds.

How are breathing, sleep and energy affected?

Both colds and sinusitis can disturb sleep, but sinusitis tends to do it for longer.

A blocked nose often forces mouth breathing at night, which can cause snoring, a dry throat and frequent waking. When sinusitis drags on for weeks, the poor sleep can accumulate, leaving many people tired, less focused at work and with little energy for exercise or family time.

Recognising when a cold has become sinusitis may help you get the right care sooner and get back to restful, nasal breathing.

How does nose breathing support energy and BMR?

Your basal metabolic rate (BMR) is the energy your body burns at rest to keep the heart beating, the brain working and cells repairing. Your cells make that energy using oxygen, so how well you breathe matters.

Nose breathing helps in two ways:

• Warm, moist, filtered air. The nose warms, humidifies and filters each breath before it reaches the lungs. Conditioned air is gentler on the airway lining, which matters in Bangalore's air-conditioned offices and traffic dust. Mouth breathing skips this step and can leave the throat and airways dry.
• Nitric oxide from the sinuses. The paranasal sinuses continuously make nitric oxide (NO), a natural gas. When you breathe in through your nose, small amounts of this NO travel to the lungs, where studies suggest it may help widen tiny blood vessels and improve oxygen uptake. Mouth breathing largely bypasses it.

Nose breathing does not "boost" your BMR. That is set mainly by muscle mass, age, body size and hormones such as thyroid. But comfortable nasal breathing by day, and undisturbed breathing at night, support efficient oxygen supply and deeper sleep, which your body needs to use energy well and recover.

A simple check: sit quietly and breathe through your nose with your mouth closed for two minutes. If that feels difficult, or one side is always blocked, it is worth having your nose examined.

When should you see an ENT?

See a doctor if symptoms are lasting, worsening or severe.

• Symptoms lasting more than 10 days without improvement.
• Getting worse after initially improving.
• High fever, or fever lasting more than three to four days.
• Repeated sinus infections through the year.
• Seek urgent medical care for swelling or redness around the eyes, double or blurred vision, a severe headache, a stiff neck, confusion or forehead swelling.

How an ENT evaluates and treats it

An ENT examines the nose directly to confirm whether the sinuses are involved.

After taking your history, the ENT may perform a nasal endoscopy, using a thin camera to look for swelling, pus at the sinus openings or polyps. A CT scan is not usually needed for a first episode but may be advised if symptoms are prolonged, recurrent or complicated.

Treatment usually includes saline irrigation, steroid nasal sprays and symptom relief. Antibiotics may be considered when bacterial sinusitis is suspected, such as symptoms beyond 10 days, severe illness or double worsening. If infections keep returning, the ENT looks for an underlying cause such as allergy, a deviated septum or polyps. The right option depends on the cause.

Frequently asked questions

Does nose breathing give me more energy? It does not add energy by itself, but it delivers warm, humidified air and sinus nitric oxide to the lungs, which may help oxygen uptake. Together with better sleep, that supports the energy your body uses at rest (BMR) and during activity.

Can a cold turn into a sinus infection? Yes. A cold can swell the nasal lining and block sinus drainage, allowing sinusitis to develop. Most of these cases are still viral and settle with supportive care.

Is green mucus a sign that I need antibiotics? Not necessarily. Green or yellow mucus is common in viral colds. Duration, severity and the pattern of symptoms matter more.

Is it a cold or an allergy? Allergy usually causes itching, sneezing and clear watery discharge, often triggered by dust or pollen, without fever. A cold usually comes with a sore throat and settles within about 10 days.

References

• Lundberg JO, Farkas-Szallasi T, Weitzberg E, et al. High nitric oxide production in human paranasal sinuses. Nature Medicine. 1995;1(4):370-373.
• Lundberg JO, Settergren G, Gelinder S, et al. Inhalation of nasally derived nitric oxide modulates pulmonary function in humans. Acta Physiologica Scandinavica. 1996;158(4):343-347.
• Keck T, Leiacker R, Heinrich A, Kühnemann S, Rettinger G. Humidity and temperature profile in the nasal cavity. Rhinology. 2000;38(4):167-171.

About the author

Dr. Prashanth R Reddy is an ENT surgeon at ENTHealth360, Bangalore (MS ENT; MBA, IIM Bangalore; Seoul Rhinoplasty Fellowship), seeing patients at Sakra World Hospital, Marathahalli and in Koramangala. His practice focuses on how breathing affects sleep, energy and everyday performance.

Related reading: Why does my sinus keep coming back every few months? · How do I know if I have sinus problems?

For educational purposes only. Not a substitute for medical advice. Please consult a qualified ENT specialist.