Sandbox:Otitis externa natural history, complications, and prognosis

# Overview
The prognosis of otitis externa varies based on the presence of complications from the spread of the infectious pathogen. Without treatment, the prognosis of acute otitis externa is usually good and it is self-limited. It usually develops up to 7 days after infection. Initial symptoms include an odorless discharge from otorrhea, as well as mild otalgia and pruritus with signs of mild erythema of the ear canal. Without treatment, acute otitis externa will usually resolve without treatment within 4 days of onset. Otitis externa considered "chronic" - cases lasting more than 3 months with or without treatment - will usually persist indefinitely and will require treatment for resolution. Recurrent otitis externa usually results from otomycosis or dermatoses that do not resolve without treatment. Malignant necrotizing otitis externa usually develops when an infectiously-caused case of acute otitis externa spreads to the temporal bones, as well as bones in the ear adjacent to the canal. Without treatment, the prognosis of maligant otitis externa is usually poor due to resultant intracranial complications. Malignant otitis externa that results in palsies, osteitis of the skull base, and osteomyelitis of the temporal bone have particularly poor prognoses if left untreated. With treatment, acute and chronic otitis externa have good prognoses. The prognosis of malignant necrotizing otitis externa with treatment will vary depending on the severity of resultant complications.

# Natural History
- Acute otitis externa usually develops up to 7 days after infection from the causative pathogen.
- Initial symptoms include an odorless discharge from otorrhea, as well as mild otalgia and pruritus with signs of mild erythema of the ear canal.
- Without treatment, acute otitis externa will usually resolve without treatment within 4 days of onset.
- Patients that are immunocompromised may experience a longer duration and escalation of symptoms, including edema, suppuration, and increased otalgia.
In more severe cases of acute otitis externa, additional symptoms may include parotitis, adenopathy, and auricular cellulitis.
- In more severe cases of acute otitis externa, additional symptoms may include parotitis, adenopathy, and auricular cellulitis.
- Otitis externa considered "chronic" - cases lasting more than 3 months with or without treatment - will usually persist indefinitely and will require treatment for resolution.
This is usually the case when it is caused by a form of dermatitis as a chronic reaction to recurrent exposure to cosmetological chemical irritants.
- This is usually the case when it is caused by a form of dermatitis as a chronic reaction to recurrent exposure to cosmetological chemical irritants.
- Malignant necrotizing otitis externa usually develops when an infectiously-caused case of acute otitis externa spreads to the temporal bones, as well as bones in the ear adjacent to the canal, leading to damage and degradation.
Without treatment, malignant otitis externa will usually result in severe intra and extra cranial symptoms that include severe otalgia, difficulty swallowing, facial palsy, and cervicular lymphadenopathy, which will last indefinitely.
- Without treatment, malignant otitis externa will usually result in severe intra and extra cranial symptoms that include severe otalgia, difficulty swallowing, facial palsy, and cervicular lymphadenopathy, which will last indefinitely.

# Complications
- Complications of otitis externa include reactions to infection, as well as adverse reactions to the spread of the pathogen past the ear canal, including the following:
Abscesses in the ear canal.
Cellulitis from bacterial or fungal epithelial penetration in the otitis externa-damaged ear canal.
Perforated ear drum, manifesting with the following potential symptoms:
Hearing loss
Otalgia
Otorrhea
Tinnitus
Surfer's ear from cold water exposure and irritation.
Osteomyelitis of the temporal bone.
Malignant otitis externa: spread of the infectious cause of acute otitis externa past the ear canal is considered a complication.
Sigmoid sinus thrombosis may occur as a complication of malignant otitis externa due to intracranial spread of bacterial infection.
- Abscesses in the ear canal.
- Cellulitis from bacterial or fungal epithelial penetration in the otitis externa-damaged ear canal.
- Perforated ear drum, manifesting with the following potential symptoms:
Hearing loss
Otalgia
Otorrhea
Tinnitus
- Hearing loss
- Otalgia
- Otorrhea
- Tinnitus
- Surfer's ear from cold water exposure and irritation.
- Osteomyelitis of the temporal bone.
- Malignant otitis externa: spread of the infectious cause of acute otitis externa past the ear canal is considered a complication.
- Sigmoid sinus thrombosis may occur as a complication of malignant otitis externa due to intracranial spread of bacterial infection.

# Prognosis
- The prognosis of acute otitis externa is usually good, without treatment, due to its self-limited nature.
- Chronic otitis externa will require treatment to relieve symptoms.
Recurrent otitis externa usually results from otomycosis or dermatoses that do not resolve without treatment.
- Recurrent otitis externa usually results from otomycosis or dermatoses that do not resolve without treatment.
- Without treatment, the prognosis of maligant otitis externa is usually poor due to resultant intracranial complications.
Malignant otitis externa that results in palsies, osteitis of the skull base, and osteomyelitis of the temporal bone have particularly poor prognoses if left untreated.
- Malignant otitis externa that results in palsies, osteitis of the skull base, and osteomyelitis of the temporal bone have particularly poor prognoses if left untreated.
- With treatment, acute and chronic otitis externa have good prognoses.
- The prognosis of malignant necrotizing otitis externa with treatment will vary depending on the severity of resultant complications.