Otitis Externa - Clinicals, Diagnosis, and Management

Otorhinolaryngology

Clinicals - History

Fact Explanation
Otalgia. Due to acute inflammation of the ear canal skin and subdermis . Otalgia.
Due to acute inflammation of the ear canal skin and subdermis .
Hearing loss. It is a conductive hearing loss due to the otorrhoea and debris within the canal . Hearing loss.
It is a conductive hearing loss due to the otorrhoea and debris within the canal .
Ear fullness and itching. Due to the oedematous skin of the external auditory canal which obstructs the glands . Ear fullness and itching.
Due to the oedematous skin of the external auditory canal which obstructs the glands .
Tinnitus. It occurs as a result of the inflammatory process extending to the inner ear . Tinnitus.
It occurs as a result of the inflammatory process extending to the inner ear .
Severe, deep pain. Due to the inflammation extending to the bony-cartilaginous junction . Severe, deep pain.
Due to the inflammation extending to the bony-cartilaginous junction .
Ear discharge. It is associated with the eczematous skin reaction which occurs in the external auditory canal . Ear discharge.
It is associated with the eczematous skin reaction which occurs in the external auditory canal .
History of exposure to activities in water (eg: swimming) Cerumen creates a slightly acidic pH that inhibits infection. This can be altered by water exposure. Additionally, several causative organisms are present in swimming pools and similar places . History of exposure to activities in water (eg: swimming)
Cerumen creates a slightly acidic pH that inhibits infection. This can be altered by water exposure. Additionally, several causative organisms are present in swimming pools and similar places .
Regular cleaning of the ear canal. It removes cerumen, which is an important barrier to moisture and infection . Regular cleaning of the ear canal.
It removes cerumen, which is an important barrier to moisture and infection .

Clinicals - Examination

Fact Explanation
Tenderness on palpation of the tragus or applying traction to the pinna. Due to traction on the external auditory canal, the skin of which has undergone acute inflammatory changes . Tenderness on palpation of the tragus or applying traction to the pinna.
Due to traction on the external auditory canal, the skin of which has undergone acute inflammatory changes .
Erythema, edema, and narrowing of the external auditory canal with an associated purulent or serous discharge on otoscopic examination. As a result of cellulitis of the ear canal skin and subdermis , with an associated eczematous skin reaction . Erythema, edema, and narrowing of the external auditory canal with an associated purulent or serous discharge on otoscopic examination.
As a result of cellulitis of the ear canal skin and subdermis , with an associated eczematous skin reaction .
Conductive hearing loss during tuning fork examination. It is due to the otorrhoea and debris within the canal . Conductive hearing loss during tuning fork examination.
It is due to the otorrhoea and debris within the canal .
Inflamed tympanic membrane on otoscopic examination. Due to acute inflammation involving the tympanic membrane . Inflamed tympanic membrane on otoscopic examination.
Due to acute inflammation involving the tympanic membrane .
Preauricular, parotid and cervical lymphadenopathy. The external auditory canal is drained by these lymph nodes. Therefore infection spreading via lymphatics can cause lymphadenopathy in these groups . Preauricular, parotid and cervical lymphadenopathy.
The external auditory canal is drained by these lymph nodes. Therefore infection spreading via lymphatics can cause lymphadenopathy in these groups .
Tenderness in the region of the ipsilateral parotid gland and temporomandibular joint. Infection can spread through the fissures of santorini to these regions . Tenderness in the region of the ipsilateral parotid gland and temporomandibular joint.
Infection can spread through the fissures of santorini to these regions .
Nerve palsies involving VII, IX, X, XI and XII cranial nerves. Medial spread of infection to the infratemporal fossa leads to involvement of cranial bones and possibly to osteomyelitis of the base of the skull from which these nerves leave the cranium . Nerve palsies involving VII, IX, X, XI and XII cranial nerves.
Medial spread of infection to the infratemporal fossa leads to involvement of cranial bones and possibly to osteomyelitis of the base of the skull from which these nerves leave the cranium .
Granulation tissue or exposed bone seen on the floor of the canal at the bony–cartilaginous junction on otoscopic examination. This occurs in malignant otitis externa caused most often by Pseudomonas aeruginosa which produces lytic enzymes, including endotoxin, collagenase, and elastase, causing a necrotizing vasculitis and endarteritis that enable invasion of surrounding tissue. This is later replaced by granulation tissue . Granulation tissue or exposed bone seen on the floor of the canal at the bony–cartilaginous junction on otoscopic examination.
This occurs in malignant otitis externa caused most often by Pseudomonas aeruginosa which produces lytic enzymes, including endotoxin, collagenase, and elastase, causing a necrotizing vasculitis and endarteritis that enable invasion of surrounding tissue. This is later replaced by granulation tissue .

Investigations - Diagnosis

Fact Explanation
History and examination is sufficient to come to a diagnosis. Certain hallmark signs such as tenderness of the tragus, pinna, or both, that is often intense and disproportionate to what might be expected based on visual inspection would easily point towards a diagnosis . History and examination is sufficient to come to a diagnosis.
Certain hallmark signs such as tenderness of the tragus, pinna, or both, that is often intense and disproportionate to what might be expected based on visual inspection would easily point towards a diagnosis .
Gram stain and culture of discharge. Some researchers have demonstrated the polymicrobial nature of otits externa in one third of patients and the role of anaerobic
bacteria in one quarter, emphasizing the need to obtain both anaerobic and aerobic cultures in patients who have otits externa that does not respond to treatment .
Gram stain and culture of discharge.
Some researchers have demonstrated the polymicrobial nature of otits externa in one third of patients and the role of anaerobic
bacteria in one quarter, emphasizing the need to obtain both anaerobic and aerobic cultures in patients who have otits externa that does not respond to treatment .

Investigations - Management

Fact Explanation
Fasting blood glucose levels. Malignant (progressive necrotizing) otitis externa is an aggressive infection that can complicate simple infection predominantly in diabetic patients due to their immunocompromised states so screening for diabetes mellitus in the elderly with infection is useful . Fasting blood glucose levels.
Malignant (progressive necrotizing) otitis externa is an aggressive infection that can complicate simple infection predominantly in diabetic patients due to their immunocompromised states so screening for diabetes mellitus in the elderly with infection is useful .
High resolution CT scan. Computed tomographgy can help delineate soft tissue inflammation and the extent of infection and bony erosion in necrotizing otitis externa . High resolution CT scan.
Computed tomographgy can help delineate soft tissue inflammation and the extent of infection and bony erosion in necrotizing otitis externa .

Management - Supportive

Fact Explanation
Acetaminophen for analgesia. Dose: 325-650 mg 6-8 hourly. It inhibits COX-3 enzyme in the brain and spinal cord, thereby reducing production of prostaglandin, which is an important element in the pain pathway . Acetaminophen for analgesia. Dose: 325-650 mg 6-8 hourly.
It inhibits COX-3 enzyme in the brain and spinal cord, thereby reducing production of prostaglandin, which is an important element in the pain pathway .
Use of earplugs while swimming. Cerumen creates a slightly acidic pH that inhibits infection. This can be altered by water exposure. Additionally, several causative organisms are present in swimming pools and similar places . Use of earplugs while swimming.
Cerumen creates a slightly acidic pH that inhibits infection. This can be altered by water exposure. Additionally, several causative organisms are present in swimming pools and similar places .
Avoidance of manipulation of the ear canal. To avoid irritation and maceration of the skin which are known predisposing factors for otitis externa . Avoidance of manipulation of the ear canal.
To avoid irritation and maceration of the skin which are known predisposing factors for otitis externa .

Management - Specific

Fact Explanation
Removal of debris from the ear canal - Gentle cleaning with a soft plastic curette or a small Frazier suction tip under direct vision. To ensure adequate delivery of the topical medication . Removal of debris from the ear canal - Gentle cleaning with a soft plastic curette or a small Frazier suction tip under direct vision.
To ensure adequate delivery of the topical medication .
Hydrocortisone and acetic acid otic solution. Dose: 3-5 drops to the affected ear 4-6 times per day. Steroids reduce inflammation while acidic solutions lower the pH of the canal, thereby inhibiting growth of organisms which prefer an alkaline environment . Hydrocortisone and acetic acid otic solution. Dose: 3-5 drops to the affected ear 4-6 times per day.
Steroids reduce inflammation while acidic solutions lower the pH of the canal, thereby inhibiting growth of organisms which prefer an alkaline environment .
Ofloxacin otic preparation. Dose: 10 drops 4 times a day. Studies prove an increase in causative organism susceptibility and bacteriological cure with the use of quinolones when compared to non-quinolone antibiotics . Ofloxacin otic preparation. Dose: 10 drops 4 times a day.
Studies prove an increase in causative organism susceptibility and bacteriological cure with the use of quinolones when compared to non-quinolone antibiotics .
Oral antibiotics (eg: ciprofloxacin) When there is spread of infection beyond the external auditory canal such as cellulitis of surrounding structures or lymphadenitis . Oral antibiotics (eg: ciprofloxacin)
When there is spread of infection beyond the external auditory canal such as cellulitis of surrounding structures or lymphadenitis .
IV antibiotics. It is used in necrotizing otitis externa which is a severe variant that usually is caused
by P. aeruginosa and is associated with systemic invasion .
IV antibiotics.
It is used in necrotizing otitis externa which is a severe variant that usually is caused
by P. aeruginosa and is associated with systemic invasion .
Placement of an ear wick. It is used if the canal walls are too swollen to allow penetration of the drug along its length . Placement of an ear wick.
It is used if the canal walls are too swollen to allow penetration of the drug along its length .

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