Link between chickenpox and shingles

Primary infection with varicella zoster virus causes chickenpox, usually during childhood.

Although chickenpox typically presents with easily identified signs and symptoms, some cases are mild and may not be recognised.

Chickenpox in adults can be more severe. If seen within 24 hours of the rash starting an antiviral may be given, so adult patients with early chickenpox should be referred to a prescriber.

After the initial infection, the virus can settle in the body and remains dormant within the sensory nerve roots of the spinal cord or cranial nerves. Reactivation, years and sometimes decades later, is what causes shingles with a lifetime risk of 20-30 per cent.

It is thought that something ‘triggers’ the virus to reactivate. This trigger is usually an intercurrent illness, particularly in those who are immunocompromised or given corticosteroids (see Table 1), but often it may not be identified. Stress and significant stressful lifetime events are often implicated.

There are several myths about the relationship between chickenpox and shingles. Pharmacy teams have a role in explaining that:

• People do not “catch” shingles – it only happens to people who have previously been infected with chickenpox
• Those who have not had chickenpox cannot get shingles because there is no dormant infection to be reactivated
• Most adults will have had chickenpox – many will have had it during childhood so do not remember or were not aware of the diagnosis
• Shingles can be infectious and cause chickenpox in people who have not had it. Healthy people who have already had chickenpox will not be at risk.

Patients with suspected shingles should be advised to:

• Avoid contact with people who have not had chickenpox, particularly pregnant women, the immunocompromised (e.g. those on chemotherapy or corticosteroids) and babies younger than one month of age
• Avoid sharing clothes and towels
• Wash hands often.