Difference Between Otitis Media and Otitis Externa

Otalgia is common in both children and adults. It either could be resulted from local causes or may be referred. Depending on which part of the ear is involved, local causes can further be categorized as otitis media, where the middle ear cavity is involved, and otitis externa, where the external ear is involved. This article points out the differences between otitis media and externa with regard to its anatomy, etiology, pathology, clinical presentation, investigation findings, management and prognosis.

Otitis Media

It is the inflammation of the middle ear. Middle ear implies the middle ear cleft that is Eustachian tube, middle ear, atic, aditus, antrum and mastoid air cells.

Depending on the temporal relationship, it is further categorized as acute and chronic. Typically acute otitis media follows viral infection or upper respiratory tract infection, but soon the pyogenic organisms invade the middle ear. It is most often viral in origin and self-limiting condition.

Usually patient with otitis media at early stages presents with deafness and earache, which disturb sleep, and is throbbing in nature. Patient may run high degree of fever and is restless. At the stage of suppuration, the earache can become excruciating and following rupture of the tympanic membrane subsidence of symptoms occur. Unless resolution takes place it may lead to acute mastoiditis, subperiosteal abscess, facial paralysis, labyrinthitis, petrositis, extra dural abscess, meningitis, brain abscess or lateral sinus thrombophlebitis. Chronic otitis media resulted from cholestetoma formation, which can be either congenital or acquired in origin. Complications of chronic otitis media are almost same as acute otitis media such as pain, intracranial complications, facial weakness, meningitis etc. Erosion of the semicircular canal can lead to vertigo.

Acute otitis media is diagnosed if the tympanic membrane appears inflamed, red and bulge with loss of landmarks on otoscopic examination. A yellowish spot may be seen on the tympanic membrane where the rupture is imminent. In chronic otitis media, perforation of the tympanic membrane may be seen either centrally or peripherally. Apart from X-ray mastoid, CT scan of the temporal bone, culture and sensitivity of ear discharge, and audiogram to assess hearing are used to diagnose and assess complications.

Management of otitis media includes antibacterial therapy, decongestants, analgesics, ear toilet, dry local heat, myryngotomy, and treatment of contributory causes such as concomitantly infected tonsils, adenoids, nasal allergy, surgical treatment options and reconstructive surgeries.

In acute otitis media, prognosis is good unless it is complicated. However, children with recurrent episodes of acute otitis media, otitis media with effusion and chronic otitis media are at a high risk of developing conductive and sensorinural hearing loss.

Otitis Externa

It is the inflammation of the outer ear and the ear canal. It is further subdivided on etiological basis into infective group and reactive group. Infective group includes bacterial, fungal and viral infections while reactive group includes eczematous otitis externa, seborrhoeic otitis externa and neurodermatitis.

Usually a patient with otitis externa predominantly presents with earache, which is worsened when the outer ear is touched or pulled gently. Pulling the tragus causes pain is diagnostic of acute otitis externa in physical examination. Patient may also notice ear discharge and itchiness. Collection of debris and discharge accompanied with meatal swelling may give rise to temporary conductive hearing loss.

On otoscopic examination, the cause may be evident. Niger may appear as black headed filamentous growth and candida infections as white or creamy deposits.

Management of acute otitis externa is mainly symptomatic. It includes antibacterial therapy, analgesics, applying local heat, ear toilet and medicated wicks.

Prognosis is good if otitis externa responds well to treatment, but complications can occur if neglected. Usually elderly diabetics and those on immunosuppressive drugs are more prone to develop complications such as malignant/ necrotizing otitis externa.