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When Your Child’s Runny Nose Isn’t ‘Just A Blocked Nose’

A constantly blocked nose in children is often brushed off as “just another cold”. But when congestion lasts for weeks, recurrent, or affects sleep and school performance, there may be an underlying cause that needs attention.

In Singapore’s warm and humid environment, allergens such as house dust mite and mould can affect their nose and airways. The most common causes of a persistent blocked nose in older children are allergies, sinusitis and enlarged adenoids (adenoid hypertrophy). Understanding the differences helps parents know when to seek medical advice.

Allergies in Children

Allergic rhinitis (nasal allergies) occurs when a child’s immune system reacts to aeroallergens. Aeroallergens are allergens which fly in the air like house dust mites, mould, or pet dander. In allergic individuals, breathing in aeroallergens can result in nasal congestion, sneezing, itchy eyes or nose, post- nasal drip, coughing and wheezing.

In Singapore, allergen levels such as house dust mites are high almost all year around due to our heat and humidity. Over time, ongoing symptoms can disrupt daily life and wellbeing. Confirming the diagnosis of an aeroallergen sensitivity is important so that you can tackle the underlying trigger. If the symptoms are severe or if conventional medications are not working, one can consider allergen immunotherapy to desensitise the immune system to the allergen.

However, in Singapore, not all chronic nasal symptoms are due to aeroallergens. Especially in children who attend pre-school – frequent viral infections, bacterial rhinitis or sinusitis and adenoid hypertrophy are the underlying problem. Therefore, it is important to confirm the allergy especially as allergen reduction is hard work and costly!

Other Common Causes of a Persistent Blocked Nose in Children

1. Sinus Issues in Children

Sinusitis, also known as rhinosinusitis, can appear differently in children compared to adults. Instead of mainly facial pain, children more often develop a persistent cough, bad breath, irritability, low energy and sometimes swelling around the eyes.

Signs that may suggest sinusitis in children include:

  • A cold lasting more than 10 to 14 days
  • Persistent fever
  • Thick yellow or green nasal discharge for several days
  • Ongoing cough or post nasal drip
  • Headache or facial pain or “heaviness” in older children 
    Irritability, fatigue or swelling around the eyes

Children with untreated allergies are more likely to develop sinus problems, as ongoing nasal swelling can block normal sinus drainage and lead to repeated infections.

2. Enlarged Adenoids (Adenoid Hypertrophy)

Adenoids are small clusters of immune tissue located behind the nose. They help trap bacteria and viruses, especially in young children. Normally, they are small and do not cause problems. However, repeated infections or allergies can cause them to swell. This is known as enlarged adenoids or adenoid hypertrophy.

When enlarged, adenoids can block the nasal airway and affect breathing, sleep and ear health.

Symptoms of enlarged adenoids in children include:

  • Mouth breathing, even during the day
  • Snoring or noisy breathing during sleep
  • Persistent nasal congestion or a “stuffy” voice
  • Disturbed sleep or possible sleep apnoea
  • Frequent ear infections or hearing issues
  • Dry mouth or bad breath

If your child shows several of these signs, a medical assessment can help determine whether enlarged adenoids are the cause.

How It Affect Sleep, Learning & Growth

Nasal congestion and postnasal drip can make it hard for children to breathe comfortable when lying down causing restless sleep, snoring, or frequent waking. Poor sleep affects energy, mood, and attention, making it harder for children to learn and behave well during the day.

Overtime, untreated allergies may contribute to:

  • Poor attention
  • Slower growth
  • Reduced appetite
  • Lower energy levels
  • Tantrums and “moodiness” from poor sleep or dental issues
  • Oro-dental issues

Why Early Treatment Matters

A persistent blocked nose is not always caused by a single condition. Many children have a combination of allergies, sinus inflammation and enlarged adenoids.

Early assessment helps to:

  • Identify the main cause of symptoms such as aeroallergen allergy
  • Reduce repeated infections and discomfort
  • Improve sleep quality and breathing
  • Support healthy growth and learning

Early care reduces discomfort, prevents worsening symptoms, and protects overall health.

When to See a Doctor

If your child has persistent nasal congestion, poor sleep, or signs that allergies or ongoing (weeks to months) nasal blockage are affecting daily life, it’s important to seek medical advice.

At SBCC Baby and Clinic, our paediatric specialist can assess the severity of your child’s condition, identify potential conditions, and recommend the most appropriate treatment to support your child’s breathing, growth, and overall wellbeing.

Medically Reviewed by Dr Alison Joanne Lee
Consultant Paediatrician; Allergy and Immunology