Bite-sized advice for busy GPs
In any case of inexplicable pain affecting a single dermatome consider shingles, as often the pain will be present for up to a week before the rash appears.
Although famciclovir is easier for compliance being a once daily 750mg dose, five times daily aciclovir is approximately a quarter of the price.
Secondary infection may occur in cases of shingles, so when necessary oral antibiotics may be of benefit.
In mild cases affecting the body, oral antivirals may not be necessary. In immunocompromised patients, however, they are essential and should be started as soon as possible after diagnosis.
If shingles affects the tip of the nose, always expect the eye to be affected. In these cases eye involvement is very common. Resulting corneal scarring may be permanent and can be prevented, so aciclovir eye drops and referral to a local ophthalmologist are advisable.
Not only do oral antivirals decrease the severity of the rash, they also reduce the incidence and severity of post-herpetic neuralgia. To be most effective they need to be started early in the illness, preferably within 24 hours.
Although we are always taught that shingles is only ever unilateral and in one dermatome this isn't always true. Very rarely more than one dermatome may be affected simultaneously.
Occasionally shingles may be the cause of pain even without a rash.
Diagnosis can be made by culturing fluid from intact blisters or by direct fluorescent antibody tests. This can be a useful way of differentiating between varicella zoster virus and herpes simplex.
Vesicles around the ear and external auditory canal may herald onset of Ramsay Hunt syndrome; if you suspect this, always check the palate for similar vesicles. RHS may be accompanied by deafness, vertigo and a facial nerve palsy.
Nigel Stollery is a GP in Kibworth, Leicestershire