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Otitis Externa Differential Diagnoses

  • Author: Ariel A Waitzman, MD, FRCSC; Chief Editor: Ravindhra G Elluru, MD, PhD  more...
 
Updated: Jul 11, 2016
 
 

Diagnostic Considerations

Failure to recognize necrotizing (ie, malignant) otitis externa (OE) is a significant pitfall. A patient who is diabetic or immunocompromised with severe pain in the ear should have necrotizing OE excluded by an otolaryngologist.

Problems to be considered include the following:

  • Ear canal trauma
  • Ear canal carcinoma
  • Otitis media with a perforation or ventilation tube present
  • Chondritis
  • Cranial nerve palsy
  • Hearing loss
  • Wisdom tooth eruption
  • Intracranial abscess
  • Cavernous sinus thrombosis
  • Ramsay Hunt syndrome
  • Furuncle
  • Skull base osteomyelitis
  • Preauricular cyst and fistula
  • Lacerations
  • Atopic dermatitis
  • Cerumen impaction
  • Exostosis and osteoma
  • Foreign body
  • Acute (bullous) and chronic (granular) myringitis

Although malignant tumors of the ear canal are rare, they do occur and sometimes are misdiagnosed as OE.[18] If the condition does not respond to treatment as expected, an otolaryngologist should evaluate the patient.

Ramsay Hunt syndrome, more accurately known as herpes zoster oticus, is caused by varicella-zoster virus (VZV) infection. It is characterized by facial nerve paralysis and sensorineural hearing loss, with bullous myringitis and a vesicular eruption of the concha of the pinna and the external auditory canal (EAC). Painful OE may be present as well. Treatment includes use of an antiviral agent (eg, valacyclovir) and systemic steroids. The role of facial nerve decompression remains controversial.

A furuncle is usually caused by staphylococcal infection of a hair follicle. This infection occurs in the lateral cartilaginous hair-bearing portion of the EAC. On otoscopic examination, a furuncle appears as a localized process, which may develop into an abscess, rather than as a diffuse inflammatory process, as is characteristic of OE.

Skull base osteomyelitis occurs most often in patients who are diabetic or immunocompromised. The usual bacterial pathogen is Pseudomonas aeruginosa. Other predisposing conditions include arteriosclerosis, immunosuppression, chemotherapy, steroid use, and other immunodeficient states. The diagnosis is strongly suggested by a history of diabetes mellitus, severe otalgia, cranial neuropathies, and characteristic EAC findings.

The EAC may be filled with friable granulation tissue, which is primarily found inferiorly. Because this presentation may be identical to that of a soft tissue malignancy, prudence dictates a tissue biopsy even if a history of diabetes mellitus is present. Bare bone of the EAC floor may be exposed; small bony sequestra may be observed as well.

Computed tomography (CT) demonstrates bone erosion, and gallium scanning can be performed at points throughout treatment to monitor resolution. Treatment consists of administration of an antipseudomonal intravenous (IV) antibiotic such as ceftazidime (in some cases) or oral ciprofloxacin (in less dramatic cases). Extended treatment for at least 6 weeks is most appropriate. Hyperbaric oxygen therapy may also be effective. Surgical debridement is reserved for granulation tissue and bony sequestra.

A preauricular cyst or fistula may form as the result of abnormal development of the first and second branchial arch and may manifest as persistent discharge or recurrent infection. A draining sinus may be present anterior to the tragus; when infected, the cyst distends with pus, and the overlying skin is erythematous. Complete excision is indicated if these lesions become repeatedly infected. The facial nerve is at risk for injury during excision because of the close relation of the cyst or fistula to the superior branches of the nerve within the parotid gland.

First branchial cleft anomalies have a more complex embryologic origin than preauricular cysts and fistulas do. These lesions may not have an obvious sinus tract on the skin and may manifest as an abscess extending deeply into the EAC, the parotid, or the neck.

Full-thickness auricular lacerations may be observed after blunt or sharp trauma. These injuries are managed surgically by closing both the perichondrium and the skin. In contrast, external canal lacerations may occur after attempts to clean the ear canal with cotton-tipped applicators. These lacerations are usually managed by microscopically placing any skin flaps in their normal position, packing the ear canal, and administering topical antibiotic drops.

Atopic dermatitis resulting from sensitivity to topical antibiotic solutions is well known. Neomycin allergy occurs in as many as 5% of patients treated with the medication. Suspect drug sensitivity if worsening of symptoms associated with skin excoriation and weeping occurs in the distribution of the topical medication exposure after the application of drops.

Metal sensitivity also manifests as excoriation, erythema, and edema around the exposure site (eg, a piercing hole). A common allergen is nickel, an impurity that may be present in precious metals. Atopic dermatitis is managed by removal of the allergen (eg, an earring) and beginning topical steroids and antibiotics if the wound is secondarily infected. The diagnosis of metal sensitivity is confirmed by performing a skin patch test.

Cerumen impaction is the most common abnormality found on otoscopic examination, yet only a small proportion of the general population requires regular disimpaction because the EAC has the innate ability both to produce and to clear itself of cerumen. Cerumen may vary in color and consistency, and cerumen impaction may coexist with other pathologic conditions.

Debris in the EAC from cholesteatoma or tumors may be confused with cerumen; accordingly, considerable care is required when debridement of the EAC is attempted. Debridement may be accomplished by using microinstruments or by aspirating ear canal contents with a No. 5 or No. 7 Barton suction device under direct vision through the otoscope or microscope. Irrigation of the ear canal is another option, but use of a pressurized irrigation system entails the risk of trauma.

Exostoses and osteomas, the two most common bony lesions of the EAC, differ both histologically and clinically. Exostoses tend to arise from the anterior or posterior floor of the medial EAC (or from both simultaneously), have a sessile base, and are covered with normal-appearing skin. Osteomas may arise from any region of the bony EAC, are often pedunculated, may be single or multiple, and are covered by normal skin. Exostosis and osteomas require surgical treatment only if they are so large that they lead to a conductive hearing loss or intractable OE.

Foreign bodies in the EAC are not infrequently encountered. In children, the appearance of these foreign bodies is variable; parts of toys or even food may be found in the EAC. In adults, fragments of cotton swabs are the most common finding. Erythema and edema surrounding the foreign body are commonly present. Depending on the patient’s ability to cooperate, the foreign body may be removed under a microscope with the aid of microinstruments. 

Hearing aid or watch batteries can sometimes end up in the ear canal accidentally, both in the pediatric and in the adult population. Time to onset of symptoms can range from a few hours to a day. Like batteries accidentally placed anywhere in the body, batteries in the ear canal represent a medical emergency. Therefore, expeditious identification and removal are absolutely necessary.

Acute myringitis is usually caused by a mycoplasmal or viral infection and has been observed in both adults and children. It is characterized by hemorrhagic bullae involving the tympanic membrane and a flulike syndrome. It is self-limiting; treatment involves pain control and fever management. Chronic myringitis is defined as deepithelization of the tympanic membrane, granulation tissue formation, and discharge. Treatment includes topical application of eardrops, a caustic solution in unresponsive cases, and mechanical removal of polypoidal granulations.

Differential Diagnoses

 
 
Contributor Information and Disclosures
Author

Ariel A Waitzman, MD, FRCSC Assistant Professor of Otolaryngology, Wayne State University School of Medicine

Ariel A Waitzman, MD, FRCSC is a member of the following medical societies: Canadian Society of Otolaryngology-Head & Neck Surgery, American Academy of Otolaryngology-Head and Neck Surgery, American Medical Association, Michigan State Medical Society

Disclosure: Nothing to disclose.

Chief Editor

Ravindhra G Elluru, MD, PhD Professor, Wright State University, Boonshoft School of Medicine; Pediatric Otolaryngologist, Department of Otolaryngology, Dayton Children's Hospital Medical Center

Ravindhra G Elluru, MD, PhD is a member of the following medical societies: American Academy of Otolaryngology-Head and Neck Surgery, American Academy of Pediatrics, American Bronchoesophagological Association, American College of Surgeons, American Medical Association, Association for Research in Otolaryngology, Society for Ear, Nose and Throat Advances in Children, Triological Society, American Society for Cell Biology

Disclosure: Nothing to disclose.

Acknowledgements

Jerry Balentine, DO Professor of Emergency Medicine, New York College of Osteopathic Medicine; Executive Vice President, Chief Medical Officer, Attending Physician in Department of Emergency Medicine, St. Barnabas Hospital

Jerry Balentine, DO is a member of the following medical societies: American College of Emergency Physicians, American College of Osteopathic Emergency Physicians, American College of Physician Executives, American Osteopathic Association, and New York Academy of Medicine

Disclosure: Nothing to disclose.

anjiv K Bhalla, MD Consulting Staff, Department of Emergency Medicine, St Paul's Hospital of Vancouver, St Joseph's Hospital of Hamilton

Sanjiv K Bhalla, MD is a member of the following medical societies: American College of Emergency Physicians, British Columbia Medical Association, Canadian Association of Emergency Physicians, Canadian Medical Association, Canadian Medical Protective Association, and Ontario Medical Association

Disclosure: Nothing to disclose.

Orval Brown, MD Director of Otolaryngology Clinic, Professor, Department of Otolaryngology-Head and Neck Surgery, University of Texas Southwestern Medical Center at Dallas

Orval Brown, MD is a member of the following medical societies: American Academy of Otolaryngology-Head and Neck Surgery, American Academy of Pediatrics, American Bronchoesophagological Association, American College of Surgeons, American Medical Association, American Society of Pediatric Otolaryngology, Society for Ear, Nose and Throat Advances in Children, and Society of University Otolaryngologists-Head and Neck Surgeons

Disclosure: Nothing to disclose.

Pamela L Dyne, MD Professor of Clinical Medicine/Emergency Medicine, David Geffen School of Medicine at UCLA; Attending Physician, Department of Emergency Medicine, Olive View-UCLA Medical Center

Pamela L Dyne, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Mark W Fourre, MD Program Director, Department of Emergency Medicine, Maine Medical Center; Associate Clinical Professor, Department of Surgery, University of Vermont School of Medicine

Disclosure: Nothing to disclose.

Joseph P Garry, MD, FACSM, FAAFP Associate Professor, Department of Family and Community Medicine, University of Minnesota Medical School

Joseph P Garry, MD, FACSM, FAAFP is a member of the following medical societies: American Academy of Family Physicians, American College of Sports Medicine, American Medical Society for Sports Medicine, and Minnesota Medical Association

Disclosure: Nothing to disclose.

Gerard J Gianoli, MD Clinical Associate Professor, Department of Otolaryngology-Head and Neck Surgery, Tulane University School of Medicine; Vice President, The Ear and Balance Institute; Chief Executive Officer, Ponchartrain Surgery Center

Gerard J Gianoli, MD is a member of the following medical societies: American Academy of Otolaryngology-Head and Neck Surgery, American College of Surgeons, American Neurotology Society, American Otological Society, Society of University Otolaryngologists-Head and Neck Surgeons, and Triological Society

Disclosure: Vesticon, Inc. None Board membership

Ashutosh Kacker, MD Associate Professor of Otorhinolaryngology, Department of Otolaryngology, Weill Cornell Medical College; Associate Attending Physician, Otolaryngologist, New York Presbyterian Hospital; Attending Physician, New York Hospital of Queens; Attending Physician, Lenox Hill Hospital

Ashutosh Kacker, MD is a member of the following medical societies: American Academy of Otolaryngology-Head and Neck Surgery, American College of Surgeons, American Rhinologic Society, and Triological Society

Disclosure: Nothing to disclose.

Samuel Lee, MD, MS Resident Physician, Department of Emergency Medicine, Wayne State University School of Medicine, Detroit Receiving Hospital

Disclosure: Nothing to disclose.

John E McClay, MD Associate Professor of Pediatric Otolaryngology, Department of Otolaryngology-Head and Neck Surgery, Children's Hospital of Dallas, University of Texas Southwestern Medical School

John E McClay, MD is a member of the following medical societies: American Academy of Otolaryngic Allergy, American Academy of Otolaryngology-Head and Neck Surgery, American College of Surgeons, and American Medical Association

Disclosure: Nothing to disclose.

Adam J Rosh, MD Assistant Professor, Department of Emergency Medicine, Wayne State University/Detroit Receiving Hospital

Adam J Rosh, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Andrew L Sherman, MD, MS Associate Professor of Clinical Rehabilitation Medicine, Vice Chairman, Chief of Spine and Musculoskeletal Services, Program Director, SCI Fellowship and PMR Residency Programs, Department of Rehabilitation Medicine, University of Miami, Leonard A Miller School of Medicine

Andrew L Sherman, MD, MS is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, American Medical Association, and Association of Academic Physiatrists

Disclosure: Pfizer Honoraria Speaking and teaching

Jack A Shohet, MD President, Shohet Ear Associates Medical Group, Inc; Associate Clinical Professor, Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, School of Medicine

Jack A Shohet, MD is a member of the following medical societies: American Academy of Otolaryngology-Head and Neck Surgery, American Medical Association, American Neurotology Society, American Tinnitus Association, and California Medical Association

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

Russell D White, MD Professor of Medicine, Professor of Orthopedic Surgery, Director of Sports Medicine Fellowship Program, Medical Director, Sports Medicine Center, Head Team Physician, University of Missouri-Kansas City Intercollegiate Athletic Program, Department of Community and Family Medicine, University of Missouri-Kansas City School of Medicine, Truman Medical Center-Lakewood

Russell D White, MD, is a member of the following medical societies: Alpha Omega Alpha, American Academy of Family Physicians, American Association of Clinical Endocrinologists, American College of Sports Medicine, American Diabetes Association, and American Medical Society for Sports Medicine

Disclosure: Nothing to disclose.

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Craig C Young, MD Professor, Departments of Orthopedic Surgery and Community and Family Medicine, Medical Director of Sports Medicine, Director of Primary Care Sports Medicine Fellowship, Medical College of Wisconsin

Craig C Young, MD is a member of the following medical societies: American Academy of Family Physicians, American College of Sports Medicine, American Medical Society for Sports Medicine, and Phi Beta Kappa

Disclosure: Nothing to disclose.

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Acute otitis externa. Ear canal is red and edematous, and discharge is present.
Otitis externa with ear wick in place. Note discharge from canal and swelling of canal.
Anatomy of external and middle ear.
 
 
 
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