- Clinical science
Shingles (herpes zoster) is a dermatomal rash with painful blistering that is caused by the reactivation of the varicella-zoster virus (VZV). The initial infection with VZV usually occurs early in life, presenting as chickenpox (varicella), after which the virus remains dormant in the dorsal root ganglia. Immunocompromised individuals (e.g., from stress or as a result of naturally declining immune function with age) are at increased risk of VZV reactivation. Shingles is generally a clinical diagnosis, although further testing (e.g., PCR) may be indicated in unclear cases. Treatment with antiviral drugs, such as acyclovir, is usually effective. Potential complications include encephalitis and, particularly in the elderly population, painful postherpetic neuralgia.
VZV may also affect the cranial nerves. Involvement of the trigeminal nerve may cause visual impairment up to blindness (herpes zoster opthalmicus), while involvement of the facial and vestibulocochlear nerves can cause facial paralysis and hearing loss (herpes zoster oticus). These presentations, in particular, require urgent medical attention to prevent serious complications.
- Decline in immune function with advancing age
- Chronic stress
- acquired immune deficiency syndrome infection, () or immune reconstitution inflammatory syndrome (IRIS)
- Immunosuppressive therapy
- Primary infection (chickenpox): respiratory transmission → VZV inoculates the lymphoid tissue of the nasopharynx and, subsequently, regional lymphoid tissue → viremia + chickenpox → recovery from chickenpox, but virus remains dormant in dorsal root ganglia (unless reactivated → recurrent infection)
- Recurrent infection (shingles): VZV reactivated (e.g., due to immunocompromise) → virus replicates in the dorsal root ganglia → travels through peripheral sensory nerves to the skin → shingles (less contagious than primary infection)
- Fever, headaches, fatigue
Dermatomal distribution typically of 1–3 dermatomes on one side of the body, most commonly between T3 and L3 → torso, hips, waist, groin, and ventral region of the upper legs)
- Usually described as “burning”, “throbbing”, or “stabbing”
- may occur
- Erythematous maculopapular rash that quickly evolves into vesicular lesions
- Lesions may become necrotic (herpes zoster gangrenosum), generalized (herpes zoster generalisatus ) or may not present at all (zoster sine herpete) .
- Motor deficits (rare)
- Severe pain
- Disseminated disease (rash involves more than the primary 1–3 dermatomes) may occur in immunocompromised individuals
- Definition: reactivation of VZV in the ophthalmic division of the trigeminal nerve
- Fever and skin symptoms as in shingles (see “Symptoms/clinical findings” above)
- Involvement of the ophthalmic nerve: reduced corneal sensitivity with severe pain in the innervated regions (forehead, bridge and tip of the nose)
- Involvement of the nasociliary nerve:
- Definition: : reactivation of VZV in the geniculate ganglion, affecting the seventh (facial) and eighth (vestibulocochlear) cranial nerves (also known as Ramsay Hunt syndrome)
- Clinical features
- Diagnosis: tone audiometry
- Clinical presentation is usually sufficient for diagnosis.
- If the clinical picture is not conclusive, diagnosis is confirmed by laboratory tests (e.g., PCR, DFA test), especially if encephalitis is suspected )
- Tzanck test of lesions shows multinucleated giant cells with eosinophilic, intranuclear Cowdry A inclusions
Potential malignancies should be ruled out in a recurrent herpes zoster infection of unknown cause! References:
- Treatment of skin lesions (e.g., wet dressings with 5% aluminum acetate)
- Anti-inflammatory and analgesic therapy
- Antiviral therapy :acyclovir, valacyclovir or famciclovir
- Consider hospitalization if:
Antiviral therapy should be initiated as early as possible since the effectiveness of antiviral treatment decreases as the disease progresses!References:
- Pain management (see also acute pain management) 
- Antiviral therapy 
- Antiviral agent
- Consider adjuvant corticosteroid taper with prednisolone.
- Wound care: Keep skin dry and clean to prevent secondary bacterial infection.
- Admit to the hospital and administer antivirals IV if there are signs of complicated herpes zoster (e.g., ophthalmic herpes zoster or neurologic involvement).
- Consider an infectious disease consultation if there is concern for disseminated zoster infection.
- Neurology consult if there is concern for neurological complications (e.g., encephalitis).
- Immunization with zoster vaccine for patients > 50 years of age to prevent recurrence 
- Occurs in ∼ 10–15% of overall herpes zoster cases
- Strong association with age
- Clinical features: attacks of acute, intense pain, persisting for at least 3 months in the area previously affected by the rash
- Prognosis: Chronic pain develops in approximately 25–50% of affected individuals if remission does not occur within 12 months
- Herpes zoster encephalitis
We list the most important complications. The selection is not exhaustive.
- Chickenpox: live vaccine that is recommended for:
Shingles: live vaccine
- ≥ 50 years: zoster immunization is generally recommended