The evidence grades (A-D) and evidence-based statements (Strong Recommendation, Recommendation, Option, and No Recommendation) are repeated at the end of the "Major Recommendations" field.
1a. Differential Diagnosis: Clinicians should distinguish diffuse acute otitis externa (AOE) from other causes of otalgia, otorrhea, and inflammation of the external ear canal.
(Recommendation based on observational studies with a preponderance of benefit over risk).
Aggregate evidence quality: C, observational studies and D, expert opinion
Policy level: recommendation
1b. Modifying Factors: Clinicians should assess the patient with diffuse AOE for factors that modify management (nonintact tympanic membrane, tympanostomy tube, diabetes, immunocompromised state, prior radiotherapy).
(Recommendation based on observational studies with a preponderance of benefit over risk).
Aggregate evidence quality: C, observational studies
Policy level: recommendation
2. Pain Management: The management of diffuse AOE should include an assessment of pain. The clinician should recommend analgesic treatment based on the severity of pain.
(Strong recommendation based on well-designed randomized trials with a preponderance of benefit over harm).
Aggregate evidence quality: B, 1 randomized controlled trial limited to AOE; consistent, well-designed randomized trials of analgesics for pain relief in general
Policy level: strong recommendation
3. Initial Therapy: Clinicians should use topical preparations for initial therapy of diffuse, uncomplicated AOE. Systemic antimicrobial therapy should not be used unless there is extension outside the ear canal or the presence of specific host factors that would indicate a need for systemic therapy.
(Recommendation based on randomized controlled trials with minor limitations and a preponderance of benefit over harm).
Aggregate evidence quality: B, randomized controlled trials with minor limitations; no direct comparisons of topical vs systemic therapy
Policy level: recommendation
4. Topical Therapy: The choice of topical antimicrobial for initial therapy of diffuse AOE should be based upon efficacy, low incidence of adverse events, likelihood of adherence to therapy, and cost.
(Recommendation based on randomized trials with some heterogeneity and a preponderance of benefit over harm).
Aggregate evidence quality: B, randomized controlled trials with some heterogeneity
Policy level: recommendation
5. Drug Delivery: Clinicians should inform patients how to administer topical drops. When the ear canal is obstructed, delivery of topical preparations should be enhanced by aural toilet, placement of a wick, or both.
(Recommendation based on observational studies with a preponderance of benefit over harm).
Aggregate evidence quality: C, observational studies and D, expert opinion
Policy level: recommendation
6. Non-Intact Tympanic Membrane: When the patient has a tympanostomy tube or known perforation of the tympanic membrane, the clinician should prescribe a non-ototoxic topical preparation.
(Recommendation based on reasoning from first principles and on exceptional circumstances where validating studies cannot be performed and there is clear preponderance of benefit over harm).
Aggregate evidence quality: D, reasoning from first principles, and X, exceptional situations where validating studies cannot be performed
Policy level: recommendation
7. Outcome Assessment: If the patient fails to respond to the initial therapeutic option within 48 to 72 hours, the clinician should reassess the patient to confirm the diagnosis of diffuse AOE and to exclude other causes of illness.
(Recommendation based on observational studies and a preponderance of benefit over harm).
Aggregate evidence quality: C, observational studies
Policy level: recommendation
Definitions:
Guideline Definitions for Evidence-Based Statements
Strong Recommendation: A strong recommendation means the benefits of the recommended approach clearly exceed the harms (or that the harms clearly exceed the benefits in the case of a strong negative recommendation) and that the quality of the supporting evidence is excellent (grade A or B)*. In some clearly identified circumstances, strong recommendations may be made based on lesser evidence when high-quality evidence is impossible to obtain and the anticipated benefits strongly outweigh the harms. Implication: Clinicians should follow a strong recommendation unless a clear and compelling rationale for an alternative approach is present.
Recommendation: A recommendation means the benefits exceed the harms (or that the harms exceed the benefits in the case of a negative recommendation), but the quality of evidence is not as strong (grade B or C)*. In some clearly identified circumstances, recommendations may be made based on lesser evidence when high-quality evidence is impossible to obtain and the anticipated benefits outweigh the harms. Implication: Clinicians also should generally follow a recommendation but should remain alert to new information and sensitive to patient preferences.
Option: An option means that either the quality of evidence that exists is suspect (grade D)* or that well-done studies (grade A, B, or C)* show little clear advantage to one approach versus another. Implication: Clinicians should be flexible in their decision-making regarding appropriate practice, although they may set bounds on alternatives; patient preference should have a substantial influencing role.
No Recommendation: No recommendation means that there is both a lack of pertinent evidence (grade D)* and an unclear balance between benefits and harms. Implication: Clinicians should feel little constraint in their decision-making and be alert to new published evidence that clarifies the balance of benefit versus harm; patient preference should have a substantial influencing role.
Evidence Quality for Grades of Evidence
Grade A: Well-designed, randomized, controlled trials or diagnostic studies performed on a population similar to the guideline's target population
Grade B: Randomized, controlled trials or diagnostic studies with minor limitations; overwhelmingly consistent evidence from observational studies
Grade C: Observational studies (case-control and cohort design)
Grade D: Expert opinion, case reports, or reasoning from first principles (bench research or animal studies)
Grade X: Exceptional situations where validating studies cannot be performed and there is a clear preponderance of benefit over harm