If your child’s nasal congestion doesn’t go away — see a doctor.

The most common cause of a blocked nose is a cold or other viral respiratory infection. But that’s not the only reason it can happen. There’s a long list of possible causes. The key thing to remember: congestion from a simple cold usually lasts no more than 7–10 days.

If nasal blockage lasts longer, the mucus changes color, or your child develops other symptoms — such as facial pain, severe nasal obstruction, headache, or one-sided blockage — it’s time to see a doctor. Sometimes what seems like “just a runny nose” can hide more serious conditions that need specialist care.

ENT specialist Dr. Maryna Kryshtopava, PhD, explains the main causes of nasal congestion in children.

How a Child’s Nose Works

The nose, paranasal sinuses, throat, larynx, and trachea form one connected system — “air corridors” that filter, warm, and humidify the air we breathe. A newborn has only two sinuses — the ethmoid and maxillary. They are small and don’t fully develop until around age 7. The sphenoid sinus appears around age 3, and the frontal sinuses around age 6. The nasal septum is a thin plate of cartilage and bone dividing the nasal cavity in two. In children, it’s soft and flexible, and even a slight bend can make breathing harder. Nasal turbinates are curved bony structures inside the nose that warm, moisten, and filter the air. When they swell, they can easily block the already narrow nasal passages in children. The nasal lining is covered with microscopic hair-like structures called cilia, which sweep mucus and trapped germs out of the nose. Living on this lining is the microbiome — millions of “friendly” bacteria unique to each child, which help protect against infections.

Special features of a child’s nose:

• Narrow nasal passages — swelling develops quickly.
• Rich blood supply — congestion happens easily during inflammation.
• Developing immune system — children get sick more often than adults.

Main Causes of Nasal Congestion

Functional causes:

• Viral infections (95–98% of cases) — influenza, parainfluenza, rhinovirus, adenovirus, coronavirus.
• Bacterial complications (2–5% of cases) — more likely if symptoms last over 10 days or worsen after initial improvement.
• Post-viral congestion — slow recovery of the nasal lining, lasting up to 4 weeks.
• Allergic rhinitis.
• Vasomotor rhinitis — abnormal regulation of nasal blood vessels.

Anatomical causes:

• Enlarged adenoids (adenoid hypertrophy) or chronic adenoiditis — can cause constant nasal blockage and mouth breathing.
• Deviated nasal septum — can lead to one-sided or persistent congestion.
• Enlarged nasal turbinates (turbinate hypertrophy).
• Congenital structural abnormalities of the nose and nasopharynx.

When to See a Doctor

Seek medical advice if your child has:

• Nasal congestion for more than 10 days without improvement.
• Worsening symptoms after the first week of illness.
• Thick, discolored mucus from one side of the nose.
• High fever (39°C / 102°F or higher).
• Facial pain or pressure over the sinuses.

What You Can Do at Home

• Rinse the nose with saline solution (isotonic or lightly salted).
• Give plenty of warm fluids.
• Keep indoor air humid (ideally 40–60%).
• Use fever reducers if needed.

What to Avoid

• Giving antibiotics “just in case” — they don’t work against viruses.
• Using “immune boosters,” homeopathy, or unproven antivirals.
• Putting oils, honey, or milk in the nose — these can cause harm.
• Using nasal decongestant sprays for weeks — this can cause dependency.

Can Nasal Congestion Be Prevented?

Yes, at least partly:

• Get the flu vaccine — it helps prevent complications.
• Practice good hygiene — wash hands, use disposable tissues.
• Support your child’s health with balanced nutrition, good sleep, and regular outdoor activity.
• Treat chronic ENT conditions promptly, including enlarged adenoids or a deviated septum if they cause breathing problems.

Dr. Maryna’s Advice:
“In most cases, nasal congestion in children is temporary and clears up on its own. Your job as parents is to help your child breathe comfortably, watch their symptoms carefully, and not delay seeing a doctor if warning signs appear — to prevent complications.”