Ear infections are common in childhood, but they may be more frequent among autistic children. Research suggests ear infections are linked to autism spectrum disorder (ASD) diagnoses. This doesn’t mean ear infections cause or signal ASD.

Ear infections during childhood, particularly of the middle ear (otitis media), tend to occur after a cold or respiratory infection. They may cause symptoms like ear pain, fever, and trouble hearing.

Up to 80% of children will experience otitis media at least once during their lifetime. While people of any age can develop an ear infection, research suggests that otitis media and other ear, nose, and throat (ENT) conditions are common among autistic children.

An observational study from 2023, for example, found that upper respiratory conditions, including ear infections, were more common among children with autistic traits than those without. Researchers also found that experiencing ENT challenges in early childhood was correlated with an increased likelihood of an autism diagnosis.

A review from 2024 also found autistic children were frequently diagnosed with ear infections, hearing loss, and other ENT conditions compared to neurotypical children. In the research, 5.8% of autistic children had a history of ear infections, compared to 3% of nonautistic children.

The exact nature of this link wasn’t established, however, and different factors could be at play.

The correlation between ASD and ear infections can also be found in earlier research. A 2016 study noted that autistic children had significantly increased rates of ear infections and otitis-related complications compared to children who were not autistic.

More research is needed to understand the underlying factors of this association.

Currently, there’s no evidence of a direct cause-and-effect relationship between ear infections and autism. The same applies to other ENT infections.

The observational study from 2023, as well as an epidemiological study from 2018, suggest that frequent ear infections during childhood are linked to an increased chance of an ASD diagnosis. But that does not mean they cause autism.

In a statement, researchers from the 2023 observational work suggested that the link may result from possible changes and anatomical differences in the ears of autistic children. These differences may increase the frequency of ENT conditions but aren’t a direct cause or a result of them.

It’s also possible that autism and ear infections share contributing factors, like genetics or environmental exposures. This means that the same factors could cause or increase the chance of each, rather than one causing the other.

The antibiotic theory

Some experts theorize that antibiotic use during early childhood could alter the gastrointestinal (GI) microbiome (microorganisms) in a way that affects the immune system and contributes to the development of autism. Antibiotics are the first line of treatment for infections.

A 2018 study looking specifically at otitis media, antibiotic use, and the chance of an ASD diagnosis found a link between ear infections and autism. Researchers also found a correlation between antibiotic use and ASD.

However, they did not find any evidence that would suggest that the combination of both increased the chances of ASD.

One population-based cohort study from 2023 also found that antibiotic use during pregnancy and early childhood increased the chance of a child receiving an ASD diagnosis. The chance was lower or higher depending on the length of the exposure and the type of antibiotic used.

The findings suggest antibiotics aren’t the only component underlying the relationship between ENT infections and autism. More research is necessary to understand the link between the two.

Although more research is needed, ASD may involve differences in the anatomy of the ear as well as changes in the auditory brainstem, a complex hearing-focused network in the brain.

A 2019 literature review indicated significant structural and functional differences in the auditory brainstems of autistic people compared to neurotypical people. Symptoms associated with the findings included sound hypersensitivity, difficulty focusing with background noise, and diminished hearing capacity overall.

Autism manifests differently in each person. Not all autistic children experience hearing-related challenges or have anatomical differences in their ears. And not all children with auditory challenges or changes will receive an ASD diagnosis.

ASD is a neurodevelopmental condition that may involve structural and functional changes in the body. Because it occurs across a spectrum of possibilities, these differences may vary from person to person.

Some medical conditions beyond the ENT system seem to be common among autistic children. These may include:

Ear infections in autism are common, and children with a history of ENT (ear, nose, throat) infections may have an increased chance of receiving an autism diagnosis.

While no direct cause-and-effect relationship has been found, several factors may contribute to the link. Autistic children may be more likely to have structural and functional differences in the ear that contribute to infections, for example, and shared contributing factors may increase the likelihood of both conditions.

However, research doesn’t show that ear infections cause autism or vice versa.

More research is necessary to understand the relationship between ear infections and autism.