Differentials
Herpes zoster oticus (Ramsay Hunt syndrome)
SIGNS / SYMPTOMS
Severe otalgia, sensorineural hearing loss, vertigo, and presence of vesicles on the skin of the external auditory canal or concha.
INVESTIGATIONS
Clinical diagnosis.
Scrapings of vesicles and surrounding skin may yield multinucleated giant cells, known as Tzanck cells.
Lyme disease
SIGNS / SYMPTOMS
Skin rash (erythema migrans or other), frontal headache, fever, malaise, fatigue, myalgia, arthralgia, known tick exposure, or recent travel to Lyme disease-endemic region.
May present in identical fashion to Bell's palsy.
INVESTIGATIONS
Elevated immunoglobulins (IgM and/or IgG) to Borrelia burgdorferi by ELISA or indirect fluorescent antibody titres are demonstrated.
Western blot is then performed for confirmation.
Benign facial nerve tumour (e.g., facial nerve schwannoma)
SIGNS / SYMPTOMS
Waxing and waning or slowly progressive facial palsy.
May demonstrate uneven distribution of weakness across facial zones, with elements of synkinesis and fasciculations.
INVESTIGATIONS
Contrast-enhanced MRI of the course of the facial nerve, with fine-cut CT of the temporal bones: mass lesion.
Malignant facial nerve tumour (e.g., mucoepidermoid carcinoma of parotid gland)
SIGNS / SYMPTOMS
Insidious and slowly progressive onset of facial palsy. Palpable parotid mass.
History of skin cancer of ipsilateral face, especially squamous cell carcinoma.
INVESTIGATIONS
Contrast-enhanced MRI of the parotid gland and course of the facial nerve: mass lesion.
Blunt force trauma to face or temporal bone
SIGNS / SYMPTOMS
History of recent head trauma with immediate or delayed-onset facial palsy.
INVESTIGATIONS
Fine-cut CT of the temporal bone: temporal bone fracture.
Chronic otitis media or cholesteatoma
SIGNS / SYMPTOMS
Otorrhoea, conductive hearing loss, aural fullness, otalgia, fever.
INVESTIGATIONS
Fine-cut CT of the temporal bone: may detect evidence of mastoiditis, petrositis, or cholesteatoma.
Necrotising ('malignant') otitis externa
SIGNS / SYMPTOMS
History of diabetes or immunosuppression.
Severe otalgia, otorrhoea, oedematous external auditory canal with granulation tissue, conductive hearing loss, polycranial neuropathy (VI, VII, IX, X, IX, XII).
INVESTIGATIONS
Culture of otorrhoea: disorder is commonly caused by Pseudomonas aeruginosa and Staphylococcus species.
Fine-cut CT or, contrast-enhanced MRI of temporal bone: bony erosion and invasion of petrous apex or skull base; soft tissue outside the confines of the external auditory canal.
Radionucleotide imaging (gallium, technetium, and/or single photon emission computed tomography [SPECT]): evidence of high bone turnover.
Idiopathic orofacial granulomatosis (Melkersson-Rosenthal syndrome)
SIGNS / SYMPTOMS
Recurrent episodes of facial (or isolated lip) swelling, fissured tongue.
INVESTIGATIONS
Clinical diagnosis.
Uveoparotid fever (Heerfordt's syndrome)
SIGNS / SYMPTOMS
Fever, anterior uveitis, and parotid gland enlargement.
INVESTIGATIONS
Chest x-ray suggests sarcoidosis. Ophthalmological examination confirms uveitis. There may be non-caseating granulomas in the parotid.
Cerebrovascular accident (CVA)
SIGNS / SYMPTOMS
Cortical CVA: sparing of upper third of face, presence of other neurological deficits.
Pontine CVA: typically involves all regions of the face, presence of other neurological deficits.
INVESTIGATIONS
MRI or CT of the head shows evidence of cerebral infarct or haemorrhage.
Ramsay Hunt Syndrome
SIGNS / SYMPTOMS
Sudden-onset (<72 hours) unilateral peripheral facial palsy, severe ear/facial pain, and a vesicular ear rash or blisters. Other less common presenting symptoms include vertigo, hearing loss, tinnitus, dry eye, altered taste, and oral lesions.
INVESTIGATIONS
Clinical diagnosis. If there is uncertainty regarding aetiology, the vesicular lesions, if present, can be swabbed directly for confirmation by varicella zoster virus polymerase chain reaction.
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