Blocked Ears During or After a Flu? It Could Be Eustachian Tube Dysfunction (ETD)

Dr Gan, our ENT Specialist in Singapore, saw Mr A, who had a sudden onset of ear blockage (both sides) while recovering from a common cold. He has been wearing hearing aids for a few years for age-related hearing loss. However, he was worried when his hearing level deteriorated further during his cold. He did not have any ear pain or fluid coming out of his ears.

Blocked ears after flu or upper respiratory infections are common, and can feel worrying, especially when hearing seems reduced. In many cases, the issue is not permanent hearing damage, but pressure imbalance or fluid buildup behind the eardrum. 

Blocked ears after the flu or viral upper respiratory infection is a common reason patients visit an ENT Specialist in Singapore, more so during seasonal flu outbreaks.  Many patients notice that while their flu symptoms improve, the ear blockage persists, which can be uncomfortable and concerning in daily life. 

On examination, there was fluid noted behind his right and left eardrums (Figures 1a-c). There were no palpable neck lumps. A nasoendoscopy (scope through the nose) was performed. It showed signs of a recent cold with thick mucous and swollen mucous membranes (lining of the nose)(Figures 2a-b). There was no mass blocking the opening of the Eustachian tube at the postnasal space (PNS or “back of the nose”). A hearing test showed mixed hearing loss and a “stiff” ear drum, suggesting fluid buildup behind the ear drum.

Figure 1a – Fluid behind left eardrum (dark yellowish tinge seen)

Figure 1b – Fluid behind right eardrum (dark yellow tinge and bulge seen on eardrum)

Figure 1c – Picture of a normal left ear canal and eardrum

Figure 2a – Endoscopic view of the back of the nose showing the left eustachian tube opening (indicated by blue arrow)

Figure 2b – Endoscopic view of the back of the nose showing the right eustachian tube opening (blue arrow) and thick mucous (blue asterisks)

Why Do Ears Feel Blocked After a Cold or Flu?

Many patients ask: “Why do my ears feel blocked after I’m already recovering?”

The reason lies in how the nose and ears are connected.

As Mr A’s nasal symptoms were only 5 days and he was feeling better, it was likely that he was suffering from a viral cold (which does not need oral antibitoics). However, in view of the fluid behind the ear drum, he was given a course of oral antibiotics to fasten the resolution of the fluid. Typically, most fluid behind the ear drum resolves on its own (absorbed by body or drained through the Eustachian tube) between 1 to  3 months.

Mr A was also advised to perform maneuvers to open the Eustachian tube regularly which may fasten the resolution of the collection of fluid. These include Valsalva maneuver (blowing out against a closed mouth and nose to “pop” your ear), chewing on a gum and swallowing. Mr A was also given medications to reduce inflammation and congestion in his nose. On review in the clinic 6 weeks later, Mr A’s hearing is back to his usual level. A clinical examination and hearing test showed complete resolution of the fluid behind his ear drums.

What Is Eustachian Tube Dysfunction (ETD)?

Mr A’s ear condition is known as Otitis Media with Effusion (“Fluid behind the eardrum” aka “glue ear”). This condition occurred as a result of inflammation of the nasal lining caused by his cold.

The middle ear (the space behind the eardrum) is connected to the back of the nose by the Eustachian tube (Figures 3a-b). The Eustachian tube opens and closes during changes in environmental pressure (e.g. when one goes up the elevator, during air flight or diving) to equalise the pressure in the middle ear with that of the outside environment.

When this tube does not open properly, pressure builds up in the middle ear. This is known as eustachian tube dysfunction ETD.

In simple terms, ETD means the pressure equalising “valve” between the nose and ear is not working well. This leads to:

• Blocked or full sensation in the ear
• Muffled hearing
• Popping sounds
• Ear pressure
• Occasionally mild imbalance

However, when one has problems with the nose (e.g. sinusitis, allergic rhinitis or cold/flu), the tube may not be functioning properly, resulting in negative pressure in the middle ear and subsequent buildup of fluid behind the eardrum.

Why Can Ear Blockage Persist After Flu Recovery?

Even when nasal symptoms improve, inflammation inside the nose may take longer to settle.

This means the Eustachian tube may remain swollen and narrow for weeks after one has recovered from the flu. As a result, blocked ears after the flu can persist even though you feel “better” otherwise.

Typically, most fluid behind the eardrum resolves on its own within 2-6 weeks, but sometimes it can take up to 3 months, as the body reabsorbs it or drains it naturally through the Eustachian tube.

Figure 3a – The Eustachian Tube connects the middle ear to the back of the nose

Figure 3b – Eustachian Tube opening in the nasal cavity

Common Symptoms vs Red Flags

Common (Usually Temporary) Symptoms:

• Blocked ear sensation
• Mild hearing reduction
• Ear pressure
• Popping sounds
• Symptoms affecting both ears after a cold

When to Seek Medical Evaluation:

Medical review is advisable if:

• Symptoms last more than 6–8 weeks
• Hearing continues to worsen
• Only one ear is persistently blocked
• There is persistent ear pain
• There is fluid discharge from the ear
• There are associated neck lumps
• You have recurrent episodes

It is always good to have a scope to screen the back part of the nose (PNS or postnasal space), as one of the early presentations of cancer of the nose can be fluid behind the eardrum due to blockage of the Eustachian tube. Fortunately for Mr A, he did not have nose cancer.

While this is uncommon, persistent one-sided fluid behind the eardrum in adults should be evaluated carefully.

How ENT Specialists Assess Persistent Ear Blockage

When ear blockage persists, an ENT specialist may perform several assessments to understand the underlying cause and confirm whether conditions such as eustachian tube dysfunction ETD or fluid behind the eardrum are present:

• Ear examination (otoscopy or microscopy) – to assess the eardrum for signs of fluid, retraction, or reduced movement
• Hearing test (audiogram) – to evaluate hearing levels and determine if there is conductive or mixed hearing loss
• Tympanometry – a pressure test that helps detect fluid behind the eardrum and assess middle ear function
• Nasoendoscopy – a small scope passed through the nose to examine the back of the nose and the Eustachian tube opening

These assessments help clarify whether the ear blockage is due to temporary inflammation after flu or if further evaluation is needed.

When to See an ENT Specialist

In many cases, blocked ears after flu improve gradually as the underlying inflammation settles. A short period of observation may be reasonable if:

• Symptoms started recently after a cold or flu
• Both ears are affected
• Hearing is gradually improving

However, you should consider seeing an ENT specialist if:

• Ear blockage persists beyond a few weeks
• Hearing does not return to baseline
• Symptoms are one-sided
• There are repeated episodes after each flu
• There are associated nasal symptoms such as persistent nose blockage or blood-stained discharge

An ENT doctor assessment may include ear examination, hearing tests, and nasoendoscopy to assess the back of the nose and the Eustachian tube opening. Book a consultation with Dr Gan Eng Cern to learn more. 

Why Do Ears Stay Blocked After Flu Even When You Feel Better?

After a flu or cold, inflammation inside the nose may persist even when you feel better. This swelling can prevent the Eustachian tube from opening normally, causing pressure imbalance and fluid buildup behind the eardrum. As a result, the ear may feel blocked, or hearing may seem muffled for several weeks.