Serous Otitis

Everything you need to know about the causes, symptoms, and treatments of fluid accumulation in the middle ear.

Symptoms and Causes

Serous otitis is the accumulation of mucus in the middle ear without the presence of infection. It usually occurs as a consequence of unresolved acute otitis media or obstruction of the Eustachian tube caused by an upper respiratory tract infection. Despite its name—also referred to as otitis media with effusion—this condition is not always associated with an inflammatory process.

In most cases, there are no obvious signs of disease, and diagnosis may be delayed, particularly because it is a predominantly pediatric condition in which patients are unable to clearly express their symptoms. Otitis media with effusion has a higher incidence in infants aged between 6 and 24 months, and it is estimated that approximately 80% of children under 4 years of age experience it at some point.

The prognosis of serous otitis is generally favorable and it often resolves spontaneously or with appropriate treatment, without complications. However, if it is not detected early or does not respond adequately to therapy, it may progress to serious conditions that cause permanent damage to the ear.

Symptoms

As mentioned above, serous otitis is usually asymptomatic. When symptoms do occur, the most common are:

Hearing loss: partial hearing impairment (approximately 30–40%).
Sensation of pressure.
Dry clicking or crackling sound when swallowing.
Changes in tympanic membrane color, appearing dark gray or amber instead of bright white or light gray.
Displacement of the light reflex: when the tympanic membrane is illuminated with a light source, a bright triangular reflection is normally observed, indicating correct positioning and absence of abnormalities. If this cone of light is absent or displaced from its usual location, it is a clear sign of severe otitis affecting the shape and function of the tympanic membrane.
Immobility of the tympanic membrane, and sometimes the presence of air bubbles, during air insufflation.
Children under 5 years of age may present with speech or learning delays, often misattributed to lack of attention.
Very rarely, mild ear pain.

Causes

The most relevant causes of serous otitis include:

Enlargement of the adenoids.
Eustachian tube obstruction, usually due to adenoid hypertrophy, although it may also result from a structural abnormality.
Upper respiratory tract infections (common cold, influenza, sinusitis).
Certain types of allergies, particularly allergic rhinitis.
Benign cysts.
Malignant tumors.

Risk Factors

Factors that increase the risk of developing serous otitis include:

Age: although it can affect patients of any age, it is more common between 6 months and 5 years.
School attendance.
Autoimmune diseases affecting mucous membranes, such as Sjögren’s syndrome.
Exposure to secondhand smoke, which promotes inflammation of the airways and the Eustachian tube.
Down syndrome: patients typically have a shorter, narrower, and more horizontally positioned Eustachian tube. These anatomical features favor fluid accumulation due to impaired drainage.
Cleft palate: alteration of the palatal muscles interferes with Eustachian tube function, reducing its ventilation and drainage capacity.

Complications

The most frequent complications of serous otitis are:

Total hearing loss, which is usually reversible but may be persistent in some patients.
Learning difficulties.
Chronic otitis media.
Tympanic membrane perforation.
Tinnitus: buzzing sounds caused by the presence of fluid in the ear, which alters sound perception.

Prevention

Although otitis media with effusion cannot always be prevented, the following measures are effective in most cases:

Reducing the risk of infections:

Pneumococcal vaccination when indicated.
Frequent handwashing.
Limiting contact with individuals with infectious diseases.
Maintaining a balanced diet rich in fruits and vegetables.

Avoiding exposure to tobacco smoke.
Using earplugs when swimming in the sea or pool.
Thoroughly drying the ears after showering or bathing, without inserting rigid objects.
Avoiding prolonged bathing or swimming.

Which doctor treats serous otitis?

Serous otitis is diagnosed and treated within the specialty of otolaryngology. Pediatrics are also involved when the condition affects children.

Diagnosis

Diagnosis of serous otitis includes the following tests:

Otoscopy: examination of the ear using an instrument with a light source and magnifying lens. In addition to detecting signs of inflammation, it allows assessment of the light reflex, tympanic membrane color, cerumen accumulation, and the presence of foreign bodies.
Tympanometry: a probe is inserted into the ear canal to generate pressure changes and emit sounds while recording tympanic membrane movement and its response to sound and pressure variations. Abnormal results indicate Eustachian tube dysfunction or the presence of fluid.
Audiometry: evaluates the ability to perceive sounds of different frequencies and to understand speech. Headphones are used, and the patient indicates when they begin to hear sounds of increasing intensity.
Nasopharyngoscopy: indicated in adults but not performed in children. This procedure examines the nasopharynx (the posterior part of the nasal cavity and throat) using a flexible tube with a camera and light at its tip. It is used to detect or rule out benign cysts, malignant tumors, or obstructions due to fluid accumulation.

Treatment

Treatment of serous otitis combines different approaches with distinct objectives:

Observation: mild cases often resolve spontaneously and require only monitoring to assess progression and prevent complications.
Natural therapy: helpful in relieving symptoms and improving overall patient condition, but it does not cure the disease.

Application of dry heat to relieve pain, if present.
Nasal irrigation with saline solution to prevent mucus accumulation.

Medication: depends on the underlying cause and presenting symptoms.

Antihistamines: when otitis is allergy-related.
Corticosteroids: to reduce inflammation when present.

Myringotomy: a surgical drainage procedure in which an incision is made in the tympanic membrane to aspirate accumulated fluid. A ventilation tube is then inserted to allow normal drainage over the following months. The tube falls out spontaneously, so no additional intervention is required.
Adenoidectomy: indicated in children with enlarged adenoids to improve Eustachian tube function.