She had assumed that she had a flu-like illness but then noticed a slight red rash on her neck when looking in the mirror.
On examination she looked well but there was a small area of erythema on the right side of her neck with a few tiny blisters. The area was tender to touch. Otherwise there was no rash over the rest of her body. What is the diagnosis, management and differential diagnosis?
Diagnosis and management
The diagnosis is shingles, or herpes zoster infection. Shingles is a viral infection caused by the same virus that causes chickenpox.
Before the rash appears, there is usually pain or a burning sensation over the dermatome affected and there may be increased sensitivity of the skin. This may persist for three to five days before the rash appears. The rash is initially erythematous prior to blisters forming, which increase in size over several days. Characteristically the rash remains in one dermatome and is unilateral. It may take up to three or four weeks to resolve.
Treatment is often simply analgesia, particularly if the patient is relatively young. If the patient is older, immunocompromised or has severe pain and consults within two or three days of onset of the rash then treatment with an antiviral agent such as aciclovir or famciclovir as well as analgesia may be advisable. If the rash involves the ophthalmic branch of the trigeminal nerve, referral to an ophthalmologist is advisable, as in rare cases shingles may cause blindness. Other complications include cellulitis and postherpetic neuralgia.
Possible different diagnoses
- Herpes simplex infection.
- Urticaria.
- Chickenpox.
Differential diagnosis
Herpes simplex infection
- Due to a different herpes virus.
- It may cause 'cold sores' around the mouth and face or may cause genital infection.
