According to current research, in approximately 2.5% of the general population the bones of the head develop to only 60–70% of their normal thickness in the months following birth. This genetic predisposition may explain why the section of temporal bone separating the superior semicircular canal from the cranial cavity, normally 0.8 mm thick, shows a thickness of only 0.5 mm, making it more fragile and susceptible to damage through physical head trauma or from slow erosion. An explanation for this erosion of the bone has not yet been found.

These can be both congenital or develop over time with the thinning of the otic capsule by the persistent pulsations of the intracranial pressures against the bones of the skull. Finally, disease conditions—for example cholesteatoma—can result in a labyrinthine fistula. Traumatic events, with excessive pressure changes to the inner ear such as in scuba diving, head trauma, or an extremely loud noise can lead to rupture and leakage.

Once diagnosed, the gap in the temporal bone can be repaired by surgical resurfacing of the affected bone or plugging of the superior semicircular canal. These techniques are performed by accessing the site of the dehiscence either via a middle fossa craniotomy or via a canal drilled through the transmastoid bone behind the affected ear. Bone cement has been the material most often used, in spite of its tendency to slippage and resorption, and a consequent high failure rate; recently, soft tissue grafts have been substituted.

When diagnosing, PLF should be differentiated from Ménière's disease. Tympanostomy has been reported to be a way to diagnose and cure PLF.

The majority of patients present in their mid-30s to late 40s. This is likely due to a combination of the slow growth of the bone and the decreased participation in activities associated with surfer's ear past the 30's. However surfer's ear is possible at any age and is directly proportional to the amount of time spent in cold, wet, windy weather without adequate protection.

The normal ear canal is approximately 7mm in diameter and has a volume of approximately 0.8 ml (approximately one-sixth of a teaspoon). As the condition progresses the diameter narrows and can even close completely if untreated, although sufferers generally seek help once the passage has constricted to 0.5-2mm due to the noticeable hearing impairment. While not necessarily harmful in and of itself, constriction of the ear canal from these growths can trap debris, leading to painful and difficult to treat infections.

In one study, the number of new cases of cholesteatoma in Iowa was estimated in 1975–6 to be just under one new case per 10,000 citizens per year. Cholesteatoma affects all age groups, from infants through to the elderly. The peak incidence occurs in the second decade.

Aural atresia is the underdevelopment of the middle ear and canal and usually occurs in conjunction with microtia. Atresia occurs because patients with microtia may not have an external opening to the ear canal, though. However, the cochlea and other inner ear structures are usually present. The grade of microtia usually correlates to the degree of development of the middle ear.

Microtia is usually isolated, but may occur in conjunction with hemifacial microsomia, Goldenhar Syndrome or Treacher-Collins Syndrome. It is also occasionally associated with kidney abnormalities (rarely life-threatening), and jaw problems, and more rarely, heart defects and vertebral deformities.

Patulous Eustachian tube is a physical disorder. The exact causes may vary depending on the person. Weight loss is a commonly cited cause of the disorder due to the nature of the Eustachian tube itself. Fatty tissues hold the tube closed most of the time in healthy individuals. When circumstances cause overall body fat to diminish, the tissue surrounding the Eustachian tube shrinks and this function is disrupted.

Activities and substances which dehydrate the body have the same effect and are also possible causes of patulous Eustachian tube. Examples are stimulants (including caffeine) and exercise. Exercise may have a more short-term effect than caffeine or weight loss in this regard.

Pregnancy can also be a cause of patulous Eustachian tube due to the effects of pregnancy hormones on surface tension and mucus in the respiratory system.

Granulomatosis with polyangiitis can also be a cause of this disorder. It is yet unknown why.

Individuals with Nager syndrome typically have the malformations of the auricle, external auditory canal, and middle ear, including the ossicles. These malformations were found in 80% of individuals with Nager syndrome. Inner ear malformations, however, are not typically seen in this population. Middle ear disease is common among individuals with Nager syndrome. Chronic otitis media and Eustachian tube deformity can result in conductive hearing loss. For this reason, early detection and treatment for middle ear disease is crucial in this population. Sensorineural hearing loss is not a typical characteristic of Nager syndrome; however, a subset of individuals present with a mixed hearing loss, due to a progressive sensorineural component combined with the typical conductive hearing loss (Herrman "et al.", 2005).

More commonly, keratin accumulates in a pouch of tympanic membrane which extends into the middle ear space. This abnormal folding or 'retraction' of the tympanic membrane arises in one of the following ways:

- "Wittmaack's theory" : Invagination of tympanic membrane from the attic or part of pars tensa in the form of retraction pockets lead to the formation of cholesteatoma.

- "Ruedi's theory" : The basal cells of germinal layer of skin proliferate under the influence of infection and lay down keratinising squamous epithelium.

- "Habermann's theory": The epithelium from the meatus or outer drum surface grows into the middle ear through a pre-existing perforation and form cholesteatoma.

Cholesteatoma may also arise as a result of metaplasia of the middle ear mucosa or implantation following trauma.

The widespread use of wetsuits has allowed people to surf in much colder waters, which has increased the incidence and severity of surfer's ear for people who do not properly protect their ears.

- Avoid activity during extremely cold or windy conditions.

- Keep the ear canal as warm and dry as possible.

- Ear plugs

- Wetsuit hood

- Swim cap

- Diving helmet

While there is no cure, most people with tinnitus get used to it over time; for a minority, it remains a significant problem.

Some conditions that are associated with hyperacusis include:

- Acoustic shock

- Adverse drug reaction

- Anxiety

- Autism spectrum

- Lyme disease

- Migraine

- Ménière's disease

- Endolymphatic hydrops

- Multiple Sclerosis

- Noise-induced hearing loss

- Posttraumatic stress disorder

- Severe head trauma

- Superior canal dehiscence syndrome (SCDS)

- Systemic lupus erythematosus (SLE)

- Tay–Sachs disease

- Williams syndrome

Anotia ("no ear") describes a rare congenital deformity that involves the complete absence of the pinna, the outer projected portion of the ear, and narrowing or absence of the ear canal. This contrasts with microtia, in which a small part of the pinna is present. Anotia and microtia may occur unilaterally (only one ear affected) or bilaterally (both ears affected). This deformity results in conductive hearing loss, deafness.

The most common cause of hyperacusis is overexposure to excessively high decibel (sound pressure) levels.

Some come down with hyperacusis suddenly as a result of taking ear sensitizing drugs, Lyme disease, Ménière's disease, head injury, or surgery. Others are born with sound sensitivity, develop superior canal dehiscence syndrome, have had a history of ear infections, or come from a family that has had hearing problems.

Some psychoactive drugs such as LSD, methaqualone, or phencyclidine ("angel-dust") can cause hyperacusis. An antibiotic, ciprofloxacin has also been seen to be a cause, known as "ciprofloxacin-related hyperacusis".

Microtia is a congenital deformity where the pinna (external ear) is underdeveloped. A completely undeveloped pinna is referred to as anotia. Because microtia and anotia have the same origin, it can be referred to as microtia-anotia. Microtia can be unilateral (one side only) or bilateral (affecting both sides). Microtia occurs in 1 out of about 8,000–10,000 births. In unilateral microtia, the right ear is most commonly affected. It may occur as a complication of taking Accutane (isotretinoin) during pregnancy.

"20% to 40% of children with microtia/anotia will have additional defects that could suggest a syndrome."

Treacher-Collins Syndrome: (TCS) A congenital disorder caused by a defective protein known as treacle, and is characterized by craniofacial deformities; malformed or absent ears are also seen in this syndrome. The effects may be mild, undiagnosed to severe, leading to death. Because the ear defects are much different in this disorder and not only affect the outer ear, but the middle ear as well, reconstructive surgery may not help with the child's hearing and in this case a Bone Anchored Hearing Aid would be best. BAHA will only work, however if the inner ear and nerve are intact.

Goldenhar Syndrome: A rare congenital birth defect that causes abnormalities of facial development. also known as Oculoauricular Dysplasia. The facial anomalies include underdeveloped, asymmetric half of the face. The defect is capable of affecting tissue, muscle, and the underlying bone structure of the side of the face with the abnormality.

Ablepharon-macrostomia Syndrome: (AMS) A rare genetic disorder characterized by various physical anomalies which affect the craniofacial area, the skin, the fingers, and the genitals.

Fluid accumulation is the most common cause of conductive hearing loss in the middle ear, especially in children. Major causes are ear infections or conditions that block the eustachian tube, such as allergies or tumors. Blocking of the eustachian tube leads to decreased pressure in the middle ear relative to the external ear, and this causes decreased motion of both the ossicles and the tympanic membrane.

- acute or serous otitis media

- otitis media with effusion or 'glue ear'

- Perforated eardrum

- Chronic suppurative otitis media (CSOM)

- Cholesteatoma

- Otosclerosis, abnormal growth of bone in or near the middle ear

- middle ear tumour

- ossicular discontinuity as a consequence of infection or temporal bone trauma

- Congenital malformation of the ossicles. This can be an isolated phenomenon or can occur as part of a syndrome where development of the 1st and 2nd branchial arches is seen such as in Goldenhar syndrome, Treacher Collins syndrome, branchio-oto-renal syndrome etc.

- Barotrauma unequal air pressures in the external and middle ear. This can temporarily occur, for example, by the environmental pressure changes as when shifting altitude, or inside a train going into a tunnel. It is managed by any of various methods of ear clearing manoeuvres to equalize the pressures, like swallowing, yawning, or the Valsalva manoeuvre. More severe barotrauma can lead to middle ear fluid or even permanent sensorineural hearing loss.

Within the labyrinth of the inner ear lie collections of calcium crystals known as otoconia or otoliths. In patients with BPPV, the otoconia are dislodged from their usual position within the utricle, and migrate over time into one of the semicircular canals (the posterior canal is most commonly affected due to its anatomical position). When the head is reoriented relative to gravity, the gravity-dependent movement of the heavier otoconial debris (colloquially "ear rocks") within the affected semicircular canal causes abnormal (pathological) endolymph fluid displacement and a resultant sensation of vertigo. This more common condition is known as canalithiasis.

In rare cases, the crystals themselves can adhere to a semicircular canal cupula, rendering it heavier than the surrounding endolymph. Upon reorientation of the head relative to gravity, the cupula is weighted down by the dense particles, thereby inducing an immediate and sustained excitation of semicircular canal afferent nerves. This condition is termed cupulolithiasis.

There is evidence in the dental literature that malleting of an osteotome during closed sinus floor elevation, otherwise known as "osteotome sinus elevation" or "lift", transmits percussive and vibratory forces capable of detaching otoliths from their normal location and thereby leading to the symptoms of BPPV.

It can be triggered by any action which stimulates the posterior semi-circular canal, including:

- Looking up or down

- Preceding head injury

- Sudden head movement

- Rolling over in bed

- Tilting the head

BPPV may be made worse by any number of modifiers which may vary between individuals:

- Changes in barometric pressure — patients may feel increased symptoms up to two days before rain or snow

- Lack of sleep (required amounts of sleep may vary widely)

- Stress

An episode of BPPV may be triggered by dehydration, such as that caused by diarrhea. For this reason, it commonly occurs in post-operative patients who have diarrhea induced by post-operative antibiotics.

BPPV is one of the most common vestibular disorders in patients presenting with dizziness; migraine is implicated in idiopathic cases. Proposed mechanisms linking the two are genetic factors and vascular damage to the labyrinth.

Although BPPV can occur at any age, it is most often seen in people over the age of 60. Besides aging, there are no major risk factors known for developing BPPV, although previous episodes of trauma to the head, or inner ear infections known as labyrinthitis, may predispose individuals to future development of BPPV.

Upon examination of a suspected case of patulous Eustachian tube, a doctor can directly view the tympanic membrane with a light and observe that it vibrates with every breath taken by the patient. A tympanogram may also help with the diagnosis. Patulous Eustachian tube is likely if brisk inspiration causes a significant pressure shift.

Patulous Eustachian tube is frequently misdiagnosed as standard congestion due to the similarity in symptoms and rarity of the disorder. Audiologists are more likely to recognize the disorder, usually with tympanometry or nasally delivered masking noise during a hearing assessment, which is highly sensitive to this condition.

When misdiagnosis occurs, a decongestant medication is sometimes prescribed. This type of medication aggravates the condition, as the Eustachian tube relies on sticky fluids to keep closed and the drying effect of a decongestant would make it even more likely to remain open and cause symptoms. The misdiagnosed patient may also have tubes surgically inserted into the eardrum, which increases the risk of ear infection and will not alleviate patulous Eustachian tube. If these treatments are tried and failed, and the doctor is not aware of the actual condition, the symptoms may even be classified as psychological.

Incidentally, patients who instead suffer from the even rarer condition of superior canal dehiscence are at risk for misdiagnosis of patulous Eustachian tube due to the similar autophony in both conditions.

Hearing loss with craniofacial syndromes is a common occurrence. Many of these multianomaly disorders involve structural malformations of the outer or middle ear, making a significant hearing loss highly likely.

Third window effect caused by:

- Superior canal dehiscence – which may require surgical correction.

- Widened vestibular aqueducts

Tinnitus is commonly thought of as a symptom of adulthood, and is often overlooked in children. Children with hearing loss have a high incidence of tinnitus, even though they do not express the condition or its effect on their lives. Children do not generally report tinnitus spontaneously and their complaints may not be taken seriously. Among those children who do complain of tinnitus, there is an increased likelihood of associated otological or neurological pathology such as migraine, juvenile Meniere’s disease or chronic suppurative otitis media. Its reported prevalence varies from 12% to 36% in children with normal hearing thresholds and up to 66% in children with a hearing loss and approximately 310% of children have been reported to be troubled by tinnitus.

The disorder can be associated with a number of psychological symptoms, anxiety, depression, social phobia, body image disorders, and patients may be subjected to discrimination, bullying and name calling especially when young. A multi-disciplinary team and parental support should include these issues.

Brain related causes are less commonly associated with isolated vertigo and nystagmus but can still produce signs and symptoms, which mimic peripheral causes. Disequilibrium is often a prominent feature.

- Degenerative: age related decline in balance function

- Infectious: meningitis, encephalitis, epidural abscess, syphilis

- Circulatory: cerebral or cerebellar ischemia or hypoperfusion, stroke, lateral medullary syndrome (Wallenberg's syndrome)

- Autoimmune: Cogan syndrome

- Structural: Arnold-Chiari malformation, hydrocephalus

- Systemic: multiple sclerosis, Parkinson's disease

- Vitamin deficiency: Vitamin B12 deficiency

- CNS or posterior neoplasms, benign or malignant

- Neurological: Vertiginous epilepsy, abasia

- Other – There are a host of other causes of dizziness not related to the ear.

- Mal de debarquement is rare disorder of imbalance caused by being on board a ship. Patients suffering from this condition experience disequilibrium even when they get off the ship. Typically treatments for seasickness are ineffective for this syndrome.

- Motion sickness – a conflict between the input from the various systems involved in balance causes an unpleasant sensation. For this reason, looking out of the window of a moving car is much more pleasant than looking inside the vehicle.

- Migraine-associated vertigo

- Toxins, drugs, medications; it is also a known symptom of carbon monoxide poisoning.