Now let's talk about otitis externa
This is inflammation of the external ear canal, or the outer ear
It's commonly called swimmer's ear.
While there's no relationship between otitis externa and the middle ear pathology such as acute otitis media,
these two diseases compose the most common causes of earaches in children.
A healthy ear canal typically has a whole range of host defenses.
Cerumen , which is earwax creates an acidic coating containing enzymes that inhibit bacterial and fungal growth in the ear canal.
The cerumen is also lipid-rich so it can prevent water from penetrating the skin and causing breakdown called maceration.
If the patient has too little cerumen, this can predispose the ear canal to infection.
But cerumen that is excessive or too viscous can lead to blockages or obstruction,
and water and debris can get trapped causing an infection.
And when these defenses fail or when the epithelium in the external auditory canal gets damaged, otitis externa can result.
It's typically localized and again it's a breakdown in the host defenses.
The two most common causes of otitis externa are: excessive moisture,
because this can elevate the pH inside the ear canal and this can wash away the protective cerumen.
Fluid can also get trapped behind the excessive cerumen or when patients use earbuds, if they're doing a lot of sweating, if they have high humidity in the environment, or from swimming.
The second is traums to the ear canal and this is when patients use cotton swabs, fingernails, patients who wear hearing aids or ear plugs
SOme patients also have disruption in the integrity of the skin and at baseline.
And these are patients with chronicskin conditions such as eczema, psoriasis, dermatitis or acne
They will always have a defect in their integrity of their epithelium increasing their risk for otitis externa.
There are multiple potential causes of otitis externa.
This includes gram negative bacteria such as pseudomonas
Proteus species like Klebsiella and Haemophilus in about 30% of infections are polymicrobial
Gram-positive bacteria can also cause otitis externa including staph aureus and staph pyogenes
This can be caused by fungus such as candida, and viruses - herpes simplex virus and herpes zoster
Signs and symptoms of otitis externa.
The most characteristic symptom, what the patient feels is discomfort,
and that's limited to that external auditory canal while the most characteristic sign which is what teh clinician will see, is erythema and swelling in the ear canal
There may or may not be discharge
Other signs and symptoms include itching, purulent drainage in the canal, pain with manipulation of the pinna or the tragus
so when you go to examine your patient that is quite painful, the patient may have decreased hearing secondary to external canal swelling and the presence of debris in the canal
and an enlarge postauricular and preauricular lymph node chain
The picture on the right demonstrates the inflamed and infected canal and the purulent discharge
On exam, the patient's usually quite uncomfortable, sometimes they're holding their ear having a hot pack to their ear
You need to try to perform an otoscopic exam and this is challenging because already the patient has a lot of pain and the clinician really needs to manipulate the external ear and try to insert a speculum to view the the tympanic membrane
There's going to be swelling and redness of the external ear canal
The clinician will note purulent material in the canal - this can be pus, this can be blood or mixture.
And the tympanic membrane, sometimes it's difficult or impossible to visualize bcause of the swelling and you just need to note this in your documentation.
The diagnosis is based on history and clinical exam.
How do we treat otitis externa?
First if you can and the patient can tolerate it, you might want to clean out the canal.
ANd this can be from irrigation or you can use a curette, you might want to get the debris out as that might be causing the problem
Once teh debris is out and the canal is clear, the patient will begin a combination eardrop and this is a combination because this has antibiotics to treat teh infection and a steroid component to help with the inflammation.
We ask out patients to lay flat on one side so that ear is facing up and then fill the ear canal with drops, sometimes it's 5, sometimes it's 10 depending on the size of the patient
and we have them lay like that for about 10 minutes or so, then they can put a cotton ball on that side, if it's bilateral, they'll flip and do the other side.
And then other than that, teh patient will try and keep their ear canals clean and dry for at least 10 days, so this include the ear plugs when showering or swimming and not inserting anything into the ear.
The patient's gonna need some sort of pain control, and this can be over the counter, analgesics like NSAIDS or Tylenol.
An ear wick can be used to pull the medication into the external ear
A heating pad can be used on the external ear for comfort,
And these infections can be difficult to treat in immunocompromised host
Swimmers can help prevent this by wearing earplugs when they swim
Or they can instill a solution of half-vinegar or hal-isopropyl alcohol after this one.
Complications of acute otitis externa are rare.
It is typically a localized process that controls these topical agents.
But if it;s not optimally treated especiallyin immunocompromised host, a potentially life-threatening infection can spread to the surrounding tissues.
Necrotizing otitis externa is an invasive infection in auditory canal and the base of the skull and this typically occurs in elderly patients with diabetes mellitus.
Mastoiditis is inflammation or infection of the mastoid bone, which is part of the temporal bone behind the ear.
Chondritis of the auricle can spread to the otitis externa to the pinna of the ear and this is most common in patients with newly-pierced ears.
Central nervous system infection can develop
And cellulitis, which is an infection of the surrouding skin.
Now remember topical ear treatments such as drops and suspensions are not effective in managing the condition once one of these complications has developed.