How do you diagnose Shingles?

Shingles (Herpes zoster)

Diagnostic Criteria:

- Unilateral dermatomal pain or itching or hyperaesthesia preceding or concomitant to a vesicular rash.

- The rash consists of groups of small blisters on a red base.

- The lesions may be very itchy and painful and progress to crusting and eventual healing over 2-4 weeks.

- The rash of shingles usually clears within 2-4 weeks, but the pain may persist for months or even years (post-herpetic neuralgia- PHN).

- The rash of shingles is usually on one side of the body, not crossing the midline, and often occurs over the chest or abdomen.

- Shingles is caused by the varicella-zoster virus, which is the same virus that causes chickenpox.

Laboratory diagnostic testing:

- The virus can be detected by the following methods:

- Polymerase chain reaction (PCR)

- Viral culture

- Direct fluorescent antibody (DFA) staining of smears from skin lesions.

Serologic studies:

- Antibody titers to varicella-zoster virus (VZV) can be used to determine immunity to VZV.

Special considerations:

- Herpes Zoster Ophthalmicus: In herpes zoster ophthalmicus, the ophthalmic division of the trigeminal nerve is involved, causing pain and rash on the forehead and around the eye. This can lead to serious eye complications, including corneal scarring, glaucoma, and even blindness.

- Herpes Zoster Oticus: In herpes zoster oticus, the geniculate ganglion of the facial nerve is involved, causing pain and rash in the ear and around the face. This can lead to hearing loss, dizziness, and facial paralysis.