PARIS, June 13, 2022 (BSS/AFP) - Ramsay Hunt syndrome (RHS), which has 
forced singer Justin Bieber to cancel his world tour, is a rare and painful 
complication of the virus that causes shingles and chickenpox.

     - What it is -

     RHS was discovered in 1907 by the neurologist of the same name. It is a 
rare neurological disorder that can inflame and paralyse the facial nerve and 
cause a painful rash around the ear or mouth. 

     - Symptoms -

     Symptoms vary from person to person, but can cause severe discomfort or 
pain. 

     Most sufferers become paralysed on one side of the face and develop an 
ear rash, according to the US National Organization for Rare Disorders 
(NORD).

     The affected facial muscles may become weak or feel stiff, preventing 
the sufferer from smiling, frowning or shutting the eye on their paralysed 
side.

     In certain cases, their speech may become slurred.

     In many instances, a reddish, painful blistering rash appears on the 
outer ear and external ear canal.

     "It's often diagnosed because of this ear rash," French infectious 
disease specialist, Benjamin Davido, told AFP.

     Sometimes the blisters spread to the mouth, soft palate and upper throat 
and ear pain spreads to the neck.

     Other possible symptoms include ringing in the ears (tinnitus), earache, 
hearing loss or hyperacusis -- where sounds appear much louder than normal -- 
nausea and vertigo. 

     - Causes -

     RHS is caused by the varicella zoster virus, which also causes 
chickenpox in children and shingles in adults.

     The virus can remain dormant for decades in a person who has had 
chickenpox as a child. 

     When it is reactivated, the carrier develops shingles and in some cases 
RHS. It is unclear why the virus reactivates and affects the facial nerve.

     - Frequency -

     RHS affects men and women in equal measure. Around five people in every 
100,000 develop the syndrome in the United States every year, according to 
one estimate cited by NORD.

     However, some researchers believe cases go undiagnosed or are 
misdiagnosed, making it difficult to determine the disorder's true frequency 
in the general population.

     Anyone who has had chickenpox can potentially develop Ramsay Hunt 
syndrome, but it is extremely rare in children, NORD said. Most cases affect 
older adults, especially those over 60, or with compromised immunity.

     - Treatment - 

     RHS is generally treated by antiviral drugs such as acyclovir and 
famciclovir, along with corticosteroids like prednisone. 

     Physiotherapy -- "which must start early on" -- usually enables the 
sufferer to make a full recovery but "around 30 percent" experience after-
effects, Davido said.