Sometimes common conditions are difficult to diagnose when
we see them out of context. Varicella is rare in immunized children but we
sometimes see it in a modified form in children previously vaccinated or in
young adults. This man was in his 70s , immunocompetent and had never had
varicella as a child or been vaccinated. He presented with a fever and malaise
and a series of vesicles on a red base at different stages of development. In a
dermatomal distribution this rash would have been diagnosed as herpes zoster
but generalized here it was late onset varicella. His aged mother in law had
recently had herpes zoster and he had been in contact with her. He was admitted
to hospital and treated with IV acyclovir for a few days and then oral
valacyclovir. If the patient had mentioned he had never had chickenpox he could
have been vaccinated after his contact with zoster in his mother in law and
this would have prevented him developing varicella. Varicella is often more
severe in adults with pneumonia and encephalitis being feared complications. An
injection of zoster immune globulin within 96 hours of exposure to the virus
can prevent the disease developing but is usually only given to
immunosuppressed patients.
