• LMN: idiopathic (Bell's palsy), iatrogenic (dental rx, linezolid), infective (herpes zoster/RHS, HIV, EBV, CMV, Lyme [1/3 of bilateral cases +/- history of tick exposure, rash/joint pain], OM, cholesteatoma, necrotising/malignant OE, trauma, neurological (Guillain-Barre, mononeuropathy), neoplastic, hypertension in pregnancy, sarcoid, RA

• UMN (forehead sparing due to bilateral innervation of forehead muscle): cerebrovascular disease, intracranial tumours, MS, syphilis, HIV, vasculitis

• Facial nerve palsy (Patient), Facial palsy UK

Bell's palsy

• Most common cause of acute LMN palsy. Prednisolone 25mg BD 10/7 & refer ENT facial nerve clinic. Bell's palsy (CKS)

Ramsay Hunt syndrome

• acute peripheral facial neuropathy associated with erythematous vesicular rash of the skin of the ear canal, auricle (also termed herpes zoster oticus) and/or mucous membrane of the oropharynx. Ear pain & vesicles +/- deaf, tinnitus/vertigo. Loss of taste anterior tongue. Can occur in the absence of rash (zoster sine herpete). Complete recovery rate <50%.

Acute facial palsy pathway (GSTT)

• Step 1: central cause (usual acute medical mx and leaflet), peripheral cause (prednisolone 25mg BD 10/7 & refer ENT facial nerve clinic)

• Step 2: Cannot fully close eye and eye red or cloudy (urgent referral ophthalmology), cannot close eye but not red or cloudy (preservative-free day time drops and night time ointment, tape eye shut at night: Transpore tape)

• Step 3: Rash or blisters in or around ear, scalp, hairline or inside mouth (RHS) or House-Brackmann score 5 or 6? Valacyclovir 1g TDS 7/7. No movement of forehead AND mouth: urgent referral ENT with facial nerve EMG/ENoG studies for consideration of facial nerve decompression