Herpes zoster

Essentials

• Herpes zoster should be identified at an early stage by the clinical picture.
• Start antiviral medication immediately for patients with immunodeficiency, if the disease is localized in the trigeminus area, or if the patient is over 60 and the disease is violent and painful.
• Treat other patients with antiviral drugs after individual consideration according to the severity of the disease. The treatment should be started within 3 days after the appearance of the skin eruption. For patients with immunodeficiency, the antiviral medication should be started even if more time has elapsed.

Aetiology

• Herpes zoster is caused by the varicella-zoster virus that has remained in the paraspinal ganglia after a varicella infection. Recurrence is not common.

Symptoms and signs

• A linear bullous rash is confined to one side of the midline and occurs most often on the trunk or face (pictures ), rarely on the extremities.
• Local pain may begin days before the rash erupts.
  • Remember herpes zoster in the differential diagnosis of chest pain and examine the patient's skin (picture ).
  • Remember the possibility of HIV in young persons with wide-spread, severe herpes zoster.
• If the patient has fever and the rash is not situated in one or two dermatomes on one side of the body, the cause may be primary Herpes simplex infection. Recurrent vesicular rash resembling herpes zoster is very likely caused by Herpes simplex.

Antiviral medication

Effect of antiviral drugs on herpes zoster

• Antiviral therapy started early
  • shortens the duration of the disease
  • speeds up healing of the skin
  • reduces need for analgesics
  • reduces the number of ocular complications
  • slightly reduces acute pain and may reduce postherpetic neuralgia .

Absolute indications

• Patients who are immunosuppressed because of the following diseases or medications should always be treated with antiviral drugs:
  • bone marrow depression (leukaemia, granulocytopenia)
  • primary immunodeficiency
  • HIV carrier state
  • any severe systemic disease
  • poorly controlled diabetes
  • antineoplastic drugs
  • continuous oral corticosteroid medication.
• Herpes zoster in the trigeminus area should always be treated because of the risk for ocular complications.
  • The risk is present if the rash is situated on one side of the nose (picture ).
  • If the eye is clearly red, the sensation of the cornea is impaired when tested with a cotton wool probe or visual acuity is decreased (possible iridocyclitis) the patient should be referred to an ophthalmologist. The referral should not delay the start of antiviral medication.

Relative indications

• Persons over 60 years of age frequently need antiviral therapy, because the clinical course usually is more severe.
• Young patients should be given antiviral drugs if the disease is especially severe.

Dosage

• Valaciclovir 1 g × 3 × 7 p.o.
  • Valaciclovir is metabolized into aciclovir and valine in the gastrointestinal tract
  • Absorption is superior to that of aciclovir.
• Famciclovir 250 mg × 3 × 7 or 500 mg × 2 × 7 p.o.
  • The effective agent is penciclovir.
• Aciclovir 800 mg × 5 × 7 p.o.
• Patients with immunodeficiency may be treated with intravenous aciclovir 10 mg/kg × 3.
• Local antiviral creams have limited efficacy in the treatment of herpes zoster.

Adverse effects

• Aciclovir, famciclovir and valaciclovir are well tolerated. Serious adverse effects are rare, but some patients may have
  • gastrointestinal symptoms
  • rashes
  • headache
  • transient increases in liver transaminase concentrations.

Contagiousness and need for isolation

• Varicella-zoster virus may be transmitted during the bullous phase.
• The patient should avoid contact with children on antineoplastic drug therapy, as the consequences of a herpes zoster infection may be serious for them. If a contact has already occurred, the child should receive zoster-hyperimmunoglobulin.

Treatment of zoster pain and postherpetic neuralgia

• Nearly all patients have pain or skin hyperaesthesia after the rash has disappeared. In the elderly the neuralgia may last for years.
• Antiviral treatment given in the acute phase slightly alleviates acute pain and reduces its duration and may reduce the incidence of postherpetic neuralgia .
• Acute zoster pain is alleviated with analgesics.
• Tricyclic antidepressants (e.g. amitriptyline 25–75 mg × 1 in the evening) may be used both to alleviate acute pain and to prevent postherpetic neuralgia .
• Both acute zoster pain and postherpetic neuralgia may also be treated with the drugs listed below . There is strong research evidence on the effectiveness of these drugs in the treatment of postherpetic neuralgia. Concerning the treatment of acute pain, only one trial has been published, reporting that oxycodone provides significant relief for acute herpes zoster pain but gabapentin does not.
  • Pregabalin starting at 75 mg × 2 and, if needed, increasing after 3–7 days to 150 mg × 2 and further up to 300 mg × 2
  • Gabapentin starting at 300 mg in the evening and increasing the dosage in 300 mg steps up to 3 600 mg/24h if needed
  • Tramadol 50–100 mg × 3
  • Lidocaine cream (5 %) or lidocaine adhesive (very expensive)
  • Capsaicin adhesive patch (8%): if the above mentioned drugs are not helpful or if contraindications prevent their use, a therapeutic trial with capsaicin adhesive is justified. The patient is referred to a unit with experience in this treatment. The adhesive patch is placed on the painful skin area for 30 to 60 minutes. The adhesive must not be used on the facial area. The treatment response is observed within a few days and it usually lasts for about 3 months.
• Strong opioids, e.g. oxycodone, can be used in the treatment of severe acute zoster pain or postherpetic neuralgia provided that the patient does not have untreated anxiety or depression or addiction problems and he/she is cooperative and able to adhere to the treatment. Long-acting (slow-release) opioid tablets are used.
• Remember to check drug interactions! Take especially into account the risk of polypharmacy in elderly patients.

Prevention of herpes zoster

• For zoster prevention, there is a vaccine on the market that reduces the risk of herpes zoster and postherpetic neuralgia in patients over 50 years of age . It contains attenuated varicella-zoster virus. The preventive effect is weak in patients over 70 years of age.
• The preventive effect of a new component vaccine, that does not contain living virus, is more than 95% irrespective of age, but this vaccine is not yet available on the market.

Related resources

• Cochrane reviews
• Other Internet resources
• Literature

Ədəbiyyat

1. Dubinsky RM, Kabbani H, El-Chami Z, Boutwell C, Ali H, Quality Standards Subcommittee of the American Academy of Neurology. Practice parameter: treatment of postherpetic neuralgia: an evidence-based report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology 2004 Sep 28;63(6):959-65.
3. Hempenstall K, Nurmikko TJ, Johnson RW, A'Hern RP, Rice AS. Analgesic therapy in postherpetic neuralgia: a quantitative systematic review. PLoS Med 2005 Jul;2(7):e164. . Finnerup NB, Otto M, McQuay HJ, Jensen TS, Sindrup SH. Algorithm for neuropathic pain treatment: an evidence based proposal. Pain 2005 Dec 5;118(3):289-305. Attal N, Cruccu G, Haanpää M, Hansson P, Jensen TS, Nurmikko T, Sampaio C, Sindrup S, Wiffen P, EFNS Task Force. EFNS guidelines on pharmacological treatment of neuropathic pain. Eur J Neurol 2006 Nov;13(11):1153-69.
4. Dworkin RH, Johnson RW, Breuer J et al. Recommendations for the management of herpes zoster. Clin Infect Dis 2007 Jan 1;44 Suppl 1():S1-26.
5. Oxman MN et al. Shingles Prevention Study Group. A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults. N Engl J Med 2005 Jun 2;352(22):2271-84.
6. Dworkin RH, Barbano RL, Tyring SK et al. A randomized, placebo-controlled trial of oxycodone and of gabapentin for acute pain in herpes zoster. Pain 2009 Apr;142(3):209-17.
7. Mou J, Paillard F, Turnbull B et al. Qutenza (capsaicin) 8% patch onset and duration of response and effects of multiple treatments in neuropathic pain patients. Clin J Pain 2014;30(4):286-94.
8. Schmader KE, Levin MJ, Gnann JW Jr et al. Efficacy, safety, and tolerability of herpes zoster vaccine in persons aged 50-59 years. Clin Infect Dis 2012;54(7):922-8.
9. Finnerup NB, Attal N, Haroutounian S et al. Pharmacotherapy for neuropathic pain in adults: a systematic review and meta-analysis. Lancet Neurol 2015;14(2):162-73.
10. Lal H, Cunningham AL, Godeaux O et al. Efficacy of an adjuvanted herpes zoster subunit vaccine in older adults. N Engl J Med 2015;372(22):2087-96.