Varicella zoster virus (VZV) reactivation in Ramsay Hunt Syndrome (RHS) and zoster sine herpete (ZSH), is the second most common cause of acute peripheral facial palsy (APFP), after Herpes Simplex Virus (HSV) in Bells palsy.
Ramsay Hunt Syndrome has been classified a rare disease by the Office Of Rare Diseases of the National Institutes of Health (USA) which means that it affects fewer than 200,000 people in the United States (population est. 300 million).
Most doctors will never encounter a case of RHS in their medical careers so widespread knowledge and understanding about the condition is limited.
Misdiagnosis as Bells palsy (BP) is a common hazard which can lead to a patient's health deteriorating rapidly.
The difficulty in diagnosis lies with current examination standards and the similarities between RHS and BP. Both sets of patients experience a sudden onset of unilateral facial paralysis (less than 48 Hrs) and in early RHS vesicular eruptions may not yet have developed. Zoster sine herpete never presents with vesicles hence this group forms the largest proportion of misdiagnosed patients. Classic RHS symptoms like severe otalgia or vertigo are often ignored by inexperienced doctors, apportioning blame to 'severe Bells palsy' or drug side-effects.
Other common misdiagnoses include bacterial ear infection, flu, sinusitis.
Laboratory tests are not routine
To correctly distinguish between RHS/ZSH and BP, laboratory tests could be performed to detect VZV blood samples, tears, vesicular fluid and vesicular skin samples. However, these studies are expensive and not routine.
The discrepancy of these misdiagnoses greatly impact the accuracy of incidence and prevalence statistics for RHS and BP. Furthermore, it implies that there are considerably more RHS patients and considerably less BP patients than previously believed.
Secondary conditions (symptoms, complications) arising from RHS can increase in probability, severity and duration without treatment and potentially fatal complications like viral encephalitis risk being overlooked.
Risks of exposure
As a complication of shingles, Ramsay Hunt Syndrome can only develop in patients who have had chickenpox so if you have never had chickenpox you can not develop RHS.
Chickenpox is a highly contagious disease which spreads easily to those who have not been previously infected. Shingles on the other hand can not be 'caught' directly. However, a person without a previous chickenpox infection may catch chickenpox (but never shingles itself) by direct contact with vesicular fluid on an RHS/shingles patient.
Continuing studies suggest that exposure to chickenpox provides natural boosting of immunity against VZV and further suppresses the dormant virus. This is thought to reduce, delay or prevent the onset of shingles.
It is expected that more widespread use of the recently developed vaccines for chickenpox and shingles will further reduce the risk of RHS.