Otorrhea is a common presenting complaint in the primary care setting.1 Although most patients with otorrhea will have acute otitis externa (AOE), chronic suppurative otitis media (CSOM), tympanostomy tube otorrhea (TTO), or acute otitis media with perforation (AOM-P),2 a comprehensive evaluation is essential to rule out more serious and potentially life-threatening etiologies. Table 1 outlines the differential diagnosis and provides key diagnostic clues in determining etiology.
Evaluation
A comprehensive history and physical examination are essential to establish the correct diagnosis. Evaluate the patient's medical and surgical histories, as well as recent and current medications, for clues to underlying nonotic etiologies and immune system compromise. Table 2 lists additional information to obtain.
Physical examination During the examination, evaluate vital signs; the oral cavity, pharynx, nose, cervical lymph nodes, and areas overlying the mastoids and sinuses; the neck; and the temporomandibular joint. Additional examination may be necessary based on findings from the history and physical examination. Of course, pay special attention to the ear. Meticulously inspect the auricle, the external auditory canal (EAC), and the surrounding skin for erythema, edema, trauma, or dermatoses. Palpate for tenderness and note any rubor. Move the pinna and tragus to evaluate for pain, and evaluate the discharge for color, consistency, odor, blood, and quantity.
Tympanic membrane (TM) Fully visualize and inspect the TM for perforations (including number, size, and location), color changes, signs of thickening and/or atrophy, prior scar formation, granulation, retraction, and vasculature pattern. Spontaneous TM rupture, including that caused by acute otitis media (AOM), is usually single and central in location. Perforated TMs due to failure to heal after tympanostomy tube (TT) removal or expulsion are single, generally occur in the anteroinferior (or occasionally the posteroinferior) quadrant, and exhibit evidence of surgical scarring peripherally. In addition, the patient will have a history of TT insertion.
The middle ear Evaluate the middle ear for an effusion or mass. Use a pneumatic otoscope to ascertain mobility. If the middle ear is obscured by the otorrhea, debris, a foreign body, or cerumen, remove the obscuring substance. This not only enables full visualization of the TM but also is part of the treatment process. Generally, the secretions can be mopped up with cottontipped applicators after fluffing the cotton, although low-pressure suction, utilizing a flexible number 5 or 7 Fr Frazier catheter, may also be used.3 Because most otorrhea is associated with some degree of EAC inflammation, the use of a curette is contraindicated, as it could cause further damage. Ear irrigation is also contraindicated because the pressure from flushing can create perforation in a weakened TM. The irrigating solution might travel into the middle ear cavity via this new perforation or a previous one, resulting in ossicular disruption and/or cochlear damage.
Removing the material If the material cannot be removed by mopping or suctioning or if it appears to be hard, flaky, and/or adherent to the EAC, then it is appropriate to instill a few drops of an otic antibiotic solution or hydrogen peroxide.3 Do this cautiously, however, to avoid inadvertently inserting the liquid into the middle ear cavity. Again, when the TM is not intact, the procedure can cause pain, vertigo, nausea, vomiting, ossicular disruption, and/or cochlear damage. Furthermore, polymyxin and aminoglycoside antibiotics are potentially ototoxic.4
If the secretions cannot be removed, attempts at removal are too painful, or the EAC is too edematous for the TM to be adequately visualized, then it is acceptable to insert a cotton ear wick with appropriate ototopical agents and then reevaluate the patient frequently. 3 Alternatively, referral to an otorhinolaryngologist would also be appropriate.
Acute otitis externa
AOE is an infectious, inflammatory condition involving one or both of the EACs. It affects people of all ages, although it is rarely seen in children younger than 2 years. AOE occurs when the EAC's normal defense mechanisms of cerumen production and migratory epithelial cells are disrupted, most frequently by increased EAC moisture and/or pH or trauma. These are the sorts of conditions that predispose the canal to an infection.3 Risk factors for AOE are listed in Table 3.
Pathogens The most common bacterial pathogens are Pseudomonas aeruginosa, which caus
es 40% to 60% of all cases, and Staphylococcus aureus, which causes approximately 15% to 30% of cases.5Escherichia coli, Proteus species, and Klebsiella6 The third most common cause, responsible for approximately 10% of all cases of AOE, is a fungus, usually Aspergillus species. The second most common fungal pathogen is Candida species.3,5
Less frequently encountered pathogens include Symptoms In addition to the otorrhea, AOE causes otalgia, which varies in intensity from mild discomfort to excruciating pain. The degree of pain often correlates with the extent of edema in the EAC. Other common symptoms include ear fullness, decreased hearing, pruritus, swelling, tenderness, and pain on mastication. If symptoms other than these are present, consider other etiologies for the otorrhea more carefully.
species.Physical examination The otorrhea itself will provide clues to the causative agent. Bacterial infections are generally associated with a white to cream-colored discharge that is moderate in amount and consistency, although it can be discolored and purulent.3 With fungal infections, the discharge is typically fluffy, more abundant, and white to off-white in color, although it can also be cream, black, gray, or aqua.3 The microspores on the hyphae are often visible during the otoscopic examination. Fungal infections are also less painful and more pruritic.5 However, if there is any doubt, use a potassium hydroxide preparation to aid in the diagnosis.
Additional physical findings include diffuse EAC erythema, edema, rubor and tenderness that might extend onto the auricle, and pain on movement of the pinna and tragus. The TM should be intact and normal in appearance. Preauricular lymphadenopathy may be present. The remainder of the physical examination should be relatively normal. If not, consider another diagnosis or a complication.
Complications These can include perforation of the TM; auricular cellulitis; external auditory canal stenosis and its associated sequelae; focal furuncle formation, especially in the lateral third of the canal; and necrotizing (or malignant) otitis externa. Necrotizing otitis externa is a potentially fatal condition that arises when the infection extends into the mastoid or temporal bones in immunocompromised patients.
Antibiotic treatment Suggested regimens for AOE include ofloxacin 0.3% twice a day; polymyxin B, neomycin, and hydrocortisone combination four times a day; and ciprofloxacin with hydrocortisone twice a day.7 Randomized controlled trials have revealed essentially equivalent treatment outcomes with all three options.3,5,8 The twice-daily regimens may increase patient compliance. When fluoroquinolones first became available, animal studies provoked concerns that articular cartilage deformities might develop in children. Since that time, systemic fluoroquinolones have been utilized in more than 1,000 children with cystic fibrosis without evidence of any joint damage.5 Furthermore, studies have demonstrated minimal, if any, systemic absorption from topically administered fluoroquinolones.5
It is unlikely that resistance will develop when fluoroquinolones are used as first-line agents because resistance to the fluoroquinolones occurs by single-step RNA mutation.5 This can happen only if the concentration of the antibiotic in the infected tissue falls below the minimum inhibitory concentration, which does not occur with ototopical utilization.5
Prevention In the past, acidifying drops, astringents, or alcohol after showering or swimming was recommended to prevent recurrences. Today, the drying method of choice is a hair dryer used on a low setting.
3 The other agents are still appropriate for prophylaxis if they are not too irritating in patients who have canal deformities, who perspire profusely, or who wear hearing aids or ear plugs.
3 A tight-fitting bathing cap has been shown to be a superior alternative to ear plugs in swimmers.
3 Other preventive measures include avoiding the insertion of anything, including cotton-tipped swabs and fingernails, into the EAC; treating excessive cerumen production with ceruminolytic agents; avoiding ear irrigation; controlling underlying dermatoses; and attempting to keep soap and shampoo out of the EAC.