Autoimmune hearing loss

Autoimmune diseases can affect various organ systems in the body - including the sensitive hearing organ. In autoimmune hearing loss, the body’s own immune system mistakenly attacks the structures of the inner ear, which can lead to progressive hearing loss. This rare but serious condition is often overlooked or confused with other forms of hearing loss. However, early detection and targeted treatment are crucial to preventing permanent damage to hearing.

What is autoimmune hearing loss

Autoimmune hearing loss is a specific form of hearing impairment in which the body’s own immune system attacks the delicate structures of the inner ear. Medically, this condition is known as autoimmune inner ear disease (AIED). Whilst the immune system normally protects the body from harmful invaders, this condition leads to a fatal malfunction: the body’s defences recognise the body’s own tissue in the inner ear as foreign and attack it. This misguided immune response leads to chronic inflammatory processes in the inner ear, which can damage the sensitive hair cells and other important structures. The exact mechanism that triggers this autoimmune reaction is not yet fully understood. However, scientists suspect that so-called molecular mimicry may play a role - whereby the immune system confuses the body’s own proteins with those of pathogens due to structural similarities. The condition is relatively rare, accounting for less than one per cent of all cases of sensorineural hearing loss. Nevertheless, it is of great clinical significance, as if left untreated it can lead to severe, irreversible hearing damage, including complete deafness.

Primary and secondary forms of the condition

Doctors distinguish between two basic forms of autoimmune hearing loss. Primary autoimmune inner ear disease is present when the autoimmune reaction affects only the hearing. This isolated form is particularly difficult to diagnose, as no other organ systems are affected and therefore key diagnostic clues are missing. However, the secondary form is more common, in which hearing loss occurs as a secondary symptom of a systemic autoimmune disease. Around 15 to 30 per cent of cases fall into this category. Systemic diseases such as Cogan’s syndrome, Wegener’s granulomatosis, rheumatoid arthritis, systemic lupus erythematosus or Sjögren’s syndrome can affect the inner ear. This distinction has important implications for diagnosis and treatment. In the secondary form, other symptoms such as joint pain, skin changes or eye problems can provide valuable clues to the underlying condition and enable targeted treatment.

Recognising characteristic symptoms

Fluctuating and progressive hearing loss

The most striking feature of autoimmune-related hearing loss is its characteristic progression. Unlike typical age-related hearing loss, which usually progresses gradually and symmetrically, autoimmune-related hearing loss often begins suddenly and on one side. The hearing loss is typically sensorineural, meaning it is caused by damage to the inner ear or the auditory nerves. A particularly characteristic symptom is the fluctuating nature of the hearing loss. Hearing ability may temporarily improve, only to deteriorate again. These fluctuations can occur over days, weeks or even months and clearly distinguish the condition from other forms of hearing loss. Many sufferers report that their hearing is worse in the morning than in the evening, or that their hearing ability changes depending on the weather. Hearing loss usually progresses over weeks to months and can then spread to the other ear. Without appropriate treatment, the condition can lead to severe hearing loss or even complete deafness.

Accompanying symptoms affecting the vestibular system

In about half of cases, autoimmune-related hearing loss is accompanied by disturbances of the vestibular system. This is because the vestibular organ is located in close anatomical proximity to the cochlea in the inner ear and is often affected by the autoimmune reaction at the same time. Vestibular symptoms can manifest as vertigo, unsteadiness when walking or general balance problems. Some patients also develop positional vertigo, which occurs only with certain head movements. These symptoms can significantly impair quality of life and lead to falls or other accidents. In addition, many affected individuals report noises in the ears such as whistling or hissing (tinnitus) as well as a sensation of fullness in the ears. These symptoms may be persistent or fluctuate, much like the hearing loss itself.

Systemic autoimmune diseases as a cause

Cogan’s syndrome

Cogan’s syndrome is a rare systemic autoimmune disorder that primarily affects the eyes and the inner ear. The condition was first described in 1945 by the American ophthalmologist David Cogan and is characterised by distinctive audiovestibular and ocular symptoms. The hearing symptoms in Cogan’s syndrome are similar to those of Meniere’s disease: sudden, progressive sensorineural hearing loss, which often develops over one to three months and can lead to deafness. This is accompanied by vertigo, tinnitus and a sensation of fullness in the ears. The ocular symptoms include inflammation of the cornea (interstitial keratitis), which can lead to visual disturbances, sensitivity to light and eye pain. In severe cases, Cogan’s syndrome can also cause inflammation of the large blood vessels, particularly the aorta. This vasculitis can result in life-threatening complications such as aortic insufficiency or aneurysms.

Granulomatosis with polyangiitis

Granulomatosis with polyangiitis (GPA), formerly known as Wegener’s disease, is a systemic vasculitis that affects small and medium-sized blood vessels. The condition is characterised by the formation of granulomatous inflammation in the airways, kidneys and other organs. Hearing loss in GPA is usually caused by involvement of the middle ear. The inflammation can lead to chronic middle ear infections, fluid in the middle ear, or even perforations of the eardrum. In some cases, the inner ear is also directly affected, leading to sensorineural hearing loss. The diagnosis is often supported by other symptoms such as chronic sinusitis, nosebleeds, pneumonia or kidney problems. Laboratory tests can detect specific antibodies (c-ANCA/PR3-ANCA), which are helpful for diagnosis.

Other relevant autoimmune disorders

Various other systemic autoimmune diseases can also lead to hearing problems. Sjögren’s syndrome, a condition that primarily affects the salivary and lacrimal glands, is associated with an increased risk of hearing loss, tinnitus and vertigo. Studies show that patients with Sjögren’s syndrome have a 1.7-fold increased risk of gradual hearing loss. Systemic lupus erythematosus can lead to vascular damage in the inner ear through the formation of immune complexes. Rheumatoid arthritis, known for its involvement of the joints, can in rare cases also affect hearing, presumably through similar inflammatory mechanisms. Inflammatory bowel diseases such as Crohn’s disease or ulcerative colitis have also been linked to hearing loss, although the exact mechanism is not yet fully understood.

Diagnostic challenges

Why diagnosis is difficult

Diagnosing autoimmune inner ear disease presents doctors with significant challenges. The main reason is that there is no specific diagnostic test that can definitively confirm the condition. Diagnosis is therefore typically a process of exclusion, in which other possible causes of hearing loss must be systematically ruled out. The rarity of the condition further contributes to the problem. As AIED accounts for only a very small proportion of all cases of sensorineural hearing loss, many doctors do not immediately consider this possibility. Often, other, more common causes such as sudden sensorineural hearing loss, acoustic neuroma or age-related hearing loss are initially considered. Another problem is the variable nature of the symptoms. Whilst some patients exhibit the classic fluctuating hearing loss, others may have atypical courses, which further complicate the diagnosis.

Audiological examinations

to determine the cause of hearing loss. In cases of autoimmune hearing loss, sensorineural hearing loss is typically observed, which is often asymmetrical. It is particularly important to document the temporal progression of the hearing loss symptoms. Repeated hearing tests over an extended period can reveal the characteristic fluctuations that are crucial for diagnosis. Measuring speech intelligibility and otoacoustic emissions can also provide valuable information. Balance tests such as electronystagmography or caloric testing are particularly relevant when the patient complains of dizziness or balance problems.

Laboratory diagnostics and imaging

Blood tests play an important role in the differential diagnosis. Although there are no specific markers for AIED, various laboratory values may indicate an autoimmune disorder. These include general inflammatory markers such as ESR and CRP, as well as specific autoantibodies such as antinuclear antibodies (ANA), rheumatoid factor or ANCA antibodies. If certain systemic diseases are suspected, further specific antibodies are tested for, such as anti-Ro/SSA and anti-La/SSB antibodies in Sjögren’s syndrome or anti-dsDNA in systemic lupus erythematosus. Imaging techniques are essential to rule out other causes of hearing loss. An MRI of the brain and inner ear canals using contrast medium can detect tumours such as acoustic neuromas, inflammatory changes or vascular lesions. In some cases, a high-resolution CT scan of the temporal bone may also be useful to identify structural abnormalities.

Treatment approaches and therapeutic options

Drug therapy

The aim of drug treatment for autoimmune hearing loss is to suppress the excessive immune response and reduce inflammation in the inner ear. Corticosteroids are the first-line treatment. Prednisone or prednisolone are typically administered in high doses (1 - 2 mg/kg body weight) over several weeks, followed by a gradual reduction in dosage. The initial response rate to corticosteroids is relatively high - around 70 per cent of patients show an improvement in hearing. However, long-term success is limited. Only around 14 per cent of patients benefit permanently from steroid therapy. In most affected individuals, symptoms return once the steroid dose is reduced. If corticosteroids are ineffective or not tolerated, other immunosuppressive drugs are used. Methotrexate, originally a cancer drug, is used in low doses as an immunosuppressant and has proven effective in some patients. Other options include azathioprine, cyclophosphamide or newer biologics such as TNF-alpha inhibitors.

Hearing aids and technical support

If drug therapy cannot adequately control the hearing loss or the hearing impairment is already too advanced, hearing aids are used for rehabilitation. In cases of mild to moderate hearing loss, modern hearing aids can significantly improve communication ability. In cases of severe hearing loss or deafness, a cochlear implant (CI) is often the only option for restoring hearing. Early implantation is important, as chronic inflammation in the inner ear can lead to ossification of the cochlea, which makes implantation technically more difficult. Interestingly, autoimmune-related inflammation can also affect the function of the implant even after cochlear implantation. Fluctuating impedance values may occur, requiring more frequent adjustment of the speech processor. Concomitant immunosuppressive therapy can stabilise these fluctuations.

Treatment of accompanying symptoms

The management of vestibular symptoms often requires a multimodal approach. Acute vertigo can be treated with anti-vertigo medication, although these drugs should only be used for a short period to avoid hindering central compensation. Vestibular rehabilitation is a key component of treatment. Special balance exercises help the brain to compensate for the deficient information from the vestibular system. Head-positioning manoeuvres can be helpful in benign paroxysmal positional vertigo (BPPV).

Prognosis and long-term care

The long-term prognosis for autoimmune-related hearing loss is highly variable and depends on various factors. The timing of the start of treatment is particularly crucial - the earlier treatment begins, the better the prospects for stabilising or even improving hearing. In patients with secondary autoimmune inner ear disease as part of a systemic autoimmune disorder, long-term immunosuppressive therapy is often required. Treatment must be coordinated with the other affected organ systems, which necessitates close collaboration between different specialist disciplines. Care should be provided on an interdisciplinary basis, involving ENT specialists, audiologists, rheumatologists and, where necessary, other specialists. Regular check-ups are necessary to monitor the course of treatment and adjust it as required. Patient education also plays an important role. Those affected must be informed about the chronic nature of the condition and learn to recognise deterioration at an early stage so that they can react quickly. With appropriate treatment and professional care, many patients can lead fulfilling lives despite the challenges.