Shingles in brief: Recognition, management, and the role of pharmacists

Introduction

Shingles is the term given colloquially to herpes zoster and is associated with a painful, self-limiting vesicular rash in a dermatomal distribution^1-3. It may be preceded by systemic symptoms, and presentation may share features with other dermatological presentations. Early identification and treatment of shingles is vital to minimise discomfort and potentially serious complications, including ongoing pain associated with postherpetic neuralgia. Pharmacists play an important role in all jurisdictions assisting with recognition and referral, alongside provision of supportive measures. In some jurisdictions pharmacists may also diagnose shingles and prescribe or supply antiviral medications^4-6. This article follows on from our ‘Impetigo in brief’ article and provides a brief overview of the management of shingles and the role of that pharmacists can play.

Shingles^1-5

Shingles is the reactivation of previously dormant infection with varicella zoster. Following recovery from acute infection with the varicella zoster virus, the virus remains dormant in the dorsal root ganglion.^1-2

Reinfection is prevented primarily by a competent immune system. In situations where the immune system response is reduced the virus may overwhelm the immune system and cause an acute infection of the peripheral nervous system.^1-2

As such herpes zoster infection requires exposure to varicella zoster, which is common in Australia, particularly in the over 50 years cohort.³ There do not appear to be clear-cut precipitating factors², although some sources suggest triggering factors such as infection, injury or emotional stress.^1,7

The prevalence of HZ, and the severity of infection increases with age³ potentially due to age-related immune decline, among other factors. The lifetime risk of HZ for people who live to 80 years of age is around 50%.³ This trend to increasing incidence with increasing age is seen in several developed countries.⁸

In Australia, there are approximately 560 cases of HZ per 100,000 people per year across all age groups.³

Complications

Complications have been estimated to occur in between 13 to 26% of people with herpes zoster.³ The incidence and severity of complications is noted to increase with increasing age.³

The most common complication is post-herpetic neuralgia, which occurs more frequently in older adults.

Other complications include:

• Secondary infection of lesions
• Scarring
• Pneumonia
• Infections involving other body systems such as the eye (herpes opthalmicus), ear (herpes oticus) or broader central nervous system and viscera (disseminated herpes zoster)

Presentation and differential diagnosis^1-5,7

The hallmark of herpes zoster infection is a vesicular rash, on an erythematous base, in a unilateral dermatomal distribution (following a line along the dermatomes of the peripheral nervous system).^1,2

HZ presents with prodromal symptoms and localised discomfort in the area approximately 1-3 days prior to the eruption of the characteristic rash.

Prodromal symptoms include:

• Localised nerve pain (described as burning)
• Lethargy, fever, headache
• Abnormal skin sensations
• Lethargy, fever, headache

Once the rash erupts, it will typically be a crop of red papules. These are typically unilateral along a dermatomal line (see image 2 for a reminder on dermatome locations). Some lesions may appear outside of this area (satellite lesions).

Fluid-filled vesicles may continue to erupt for 3-5 days, becoming pustular and then scabbing over around 7-10 days after the initial lesions occurred.

The most common location for herpes zoster rash is the chest, neck, forehead or lower back (sacral/lumbar nerve supply regions). When nerves close to the eye or ear are involved, there are additional considerations.

Involvement of the trigeminal nerve will present with blistering around the eye and/or eyelid with pain, redness and swelling. This is referred to as herpes zoster ophthalmicus.

Involvement of the vestibulocochlear nerve presents with earache and blistering in and around the ear canal, with or without facial involvement. This is referred to as herpes zoster oticus/Ramsay Hunt syndrome.

Involvement of the central nervous system or other viscera (heart, lungs etc) is referred to as disseminated herpes zoster. It occurs more frequently in immunocompromised patients.

Diagnosis and patient history

Diagnosis is based on patient history and examination of the rash rather than laboratory confirmation. It may be required in situations where the diagnosis is uncertain, or where the patient does not recall previous exposure to varicella zoster.

A comprehensive patient history should be taken as part of the diagnosis and to assess the safety and appropriateness of potential treatment.

This should include:⁴

• Age
• Pregnancy and/or lactation status
• Nature, severity, and frequency of symptoms
• Nature of rash (examination recommended to confirm), distribution, appearance and number of lesions
• Onset and duration
• Precipitating and relieving factors
• History of past varicella zoster infection
• Underlying medical conditions
• Current and recently ceased treatments
• Strategies used to treat current symptoms and response
• Allergies or adverse reactions experienced previously
• Immunisation status for varicella and herpes zoster

Differential diagnosis

Differential diagnoses include other viral infections (herpes simplex, primary varicella zoster), impetigo, contact dermatitis, and insect bites.⁷

Red flag symptoms^4,5

Early treatment of shingles is key to prevention of complications, and it may be appropriate to treat concurrently with referral.

Note: the specifics of which populations must be immediately referred, or that pharmacists may treat and refer, are dictated by the legislative instruments and protocols associated with pharmacist prescribing and supply in the jurisdiction. Pharmacists are reminded to adhere to their jurisdictional requirements.

Referral is required in the following situations, although providing treatment alongside referral may be appropriate and permitted in some jurisdictions:

• Patient is immunocompromised
• Superinfection of lesions is present*
• Multi-dermatomal rash or disseminated zoster*
• Complications are present (eg. postherpetic neuralgia)*
• Rash affecting the face or genital area*
• Pain management is required beyond mild pain*
• Patient is pregnant (known history of varicella zoster)*
• Inadequate response to treatment
• Previous vaccination against herpes zoster
• Patient is breastfeeding a neonate⁵ (note that to protect older breastfed babies the rash should be covered)
• Complications suspected (scarring, pneumonia, neurological complications)*
• Rash present for > 72 hours
• Early presentation of pain prior to rash onset⁵

This is not an exhaustive list.

*Immediate referral required in some jurisdictions

Urgent referral to the emergency department is recommended in situations where the eye and/or ear are involved (Herpes Zoster Ophthalmicus or Herpes Zoster Oticus).^4,5

Treatment^4,5,13

Pharmacological management of herpes zoster includes antiviral therapy and pain management. Symptoms are usually self-limiting, but the use of antiviral therapy is indicated if commenced early enough.

Antiviral treatment can reduce symptoms including acute pain, rash duration, viral shedding, and the risk of complications if started within 72 hours of rash onset.⁴ For immunocompromised patients, initiation of antiviral treatment reduces complications at any stage of rash duration.⁴

As such, antiviral treatment is indicated for the treatment of adults:¹³

• Immunocompetent adults who present within 72 hours of rash eruption
• Adults with immune compromise at any stage following rash eruption

Antiviral therapy should commence as soon as possible with:¹³

*Famciclovir and valaciclovir may be more effective in reducing acute pain in adults with shingles and are considered first line. There is insufficient data to support use of famciclovir in pregnancy, and limited data to suggest valaciclovir may be safe in pregnancy.

Intravenous antiviral therapy is recommended for shingles in situations of disseminated disease, invasive disease, and nerve involvement of the eye or ear (herpes zoster opthalmicus and herpes zoster oticus).¹³ As previously noted, these presentations warrant immediate referral.

Pain management¹⁴

Mild shingles pain can be managed with oral paracetamol or nonsteroidal anti-inflammatory medications.

Ice packs may also be useful.

Neuropathic pain can be treated with lidocaine 5% patches, provided the area has no broken skin or lesions. This limits the usefulness of this treatment in an acute presentation.

Ongoing neuropathic pain (post-herpetic neuralgia) may be treated similarly to other neuropathic pain.

Non-pharmacological management advice^8,9

Non-pharmacological management includes avoiding irritation and preventing infection by strategies such as:

• Wearing loose clothing
• Keeping the area clean and dry
• Using a cooled towel on the area
• Covering the rash to avoid transmission

Covering of the lesions is recommended to reduce transmission, as herpes zoster is infectious to those who have not previously been infected with varicella zoster.^4,5,10

Vaccination against herpes zoster is recommended as the primary prevention strategy. Vaccination is recommended for people at moderate to high risk of severe illness and complications for shingles.

The Australia Immunisation Handbook recommends vaccination for:³

• People aged 50 and over (NIP funded 65 and over)
• Immunocompromised people aged 18 and over
• People aged 50 and over, living in a household with someone with a weakened immune system.

Conclusion

Early diagnosis and appropriate treatment of herpes zoster decreases the likelihood of experiencing lasting complications.

Pharmacists can play a greater role in the diagnosis and management of herpes zoster under expansion of scope of practice. An understanding of symptoms, management and referral requirements remains important for pharmacists in all areas of practice.

A thorough history can assist pharmacists to appropriately diagnose or refer patients in a timely manner and should be undertaken wherever possible. Appropriate use of antivirals within the first 72 hours of presentation is vital to management, and pharmacists should prescribe/supply or refer within that period wherever possible.

Pharmacists in all areas of practice can support patients and carers with non-pharmacological advice and referral for further treatment.

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