Shingles Summary

Definition

  • Viral infection of nerve & dermatome
  • Reactivation of varicella-zoster virus
  • Same virus as chickenpox
  • Localized to specific dermatome

Risk Factors

  • Increasing age (primary risk)
  • Immunocompromise
  • Various comorbidities
  • Female sex

Clinical Features

  • Prodromal pain & abnormal sensations
  • Dermatomal rash progression
  • Does not cross midline
  • Thorax most common location

Management

  • Antivirals within 72 hours
  • Pain management stepwise
  • Infection control until crusted
  • Referral for complications

Complications

  • Post-herpetic neuralgia
  • Ophthalmic involvement
  • Ramsay Hunt syndrome
  • Neurological complications

Prevention

  • Vaccination ≥70 years
  • Reduces incidence & severity
  • Prevents post-herpetic neuralgia

Shingles (Herpes Zoster)

Viral infection caused by reactivation of varicella-zoster virus

Introduction

Shingles (herpes zoster) is a viral infection of an individual nerve and the skin surface that is served by the nerve (dermatome). It is caused by the reactivation of the varicella-zoster virus, the same virus that causes chickenpox.

Pathophysiology

Following a chickenpox infection, which typically occurs during childhood, the varicella-zoster virus lies dormant in the dorsal root ganglia and reactivates when the immune system is weakened. Unlike chickenpox, shingles occurs years (sometimes decades) after the primary infection and symptoms are usually localised to a specific dermatome.

Transmission

People with active lesions of shingles can transmit varicella zoster virus to susceptible people to cause chickenpox. However, there is no evidence that shingles can be acquired from a person who has chickenpox.

Risk Factors

Primary Risk Factors

  • Increasing age (age-related decline in immunity)
  • Immunocompromise:
    • HIV infection
    • Lymphoproliferative malignancies
    • Immunosuppressive treatment
    • Organ transplantation

Other Risk Factors

  • Certain comorbidities:
    • Rheumatoid arthritis
    • Asthma and COPD
    • Chronic kidney disease
    • Depression, diabetes mellitus
    • Systemic lupus erythematosus
    • Wegener's granulomatosis
    • Malignancies
  • Psychological factors
  • Female sex
  • Race/ethnicity
  • Statin use

Clinical Features

Diagnosis

Diagnose shingles on the basis of typical clinical features.

Prodromal Phase

  • Abnormal skin sensations and pain in affected dermatome
  • Pain described as burning, stabbing, or throbbing
  • May be intermittent or constant
  • Can be severe enough to interfere with sleep and quality of life
  • Headache, photophobia, malaise, and fever (less common)

Rash Phase

  • Rash appears within 2-3 days (up to 7 days) in dermatomal distribution
  • Starts as maculopapular lesions → clusters of vesicles
  • New vesicles form over 3-5 days
  • Painful, itchy, and/or tingly
  • Does not cross midline of body
  • Vesicles burst and crust over within 7-10 days
  • Healing over 2-4 weeks with possible scarring and pigmentation

Distribution

  • Immunocompetent: usually thorax (T1 to L2 most common)
  • Immunocompromised: can be widespread, multiple dermatomes

Differential Diagnosis

General Shingles Differential

  • Herpes simplex virus (HSV) infection
  • Candidal skin infection
  • Contact dermatitis
  • Folliculitis
  • Impetigo
  • Insect bite or sting
  • Scabies
  • Urticaria

Ophthalmic Zoster Differential

  • Acute angle closure glaucoma
  • HSV ocular infections
  • Trigeminal neuralgia
  • Ulcerative keratitis

Management

Immediate Specialist Referral Required For:

  • Suspected serious complications (meningitis, encephalitis, myelitis)
  • Shingles in ophthalmic distribution of trigeminal nerve with:
    • Hutchinson's sign (rash on tip, side, or root of nose)
    • Visual symptoms
    • Unexplained red eye
  • Severely immunocompromised with shingles
  • Immunocompromised with severe, widespread rash or systemic illness
  • Immunocompromised child with shingles

Antiviral Treatment

Prescribe Within 72 Hours For:

  • Immunocompromise (if not severe, localized, can be followed up)
  • Non-truncal involvement (neck, limbs, perineum)
  • Moderate or severe pain
  • Moderate or severe rash
  • All people aged over 50 years (to reduce post-herpetic neuralgia)

Later Treatment Consideration

  • Consider starting up to one week after rash onset if:
    • Higher risk of severe shingles/complications
    • Continued vesicle formation
    • Older age
    • Immunocompromised
    • Severe pain

Pain Management

First-line

  • Paracetamol alone or with codeine
  • NSAIDs (e.g., ibuprofen)

Second-line

  • Amitriptyline (off-label)
  • Duloxetine (off-label)
  • Gabapentin
  • Pregabalin

Corticosteroids

  • Consider in first 2 weeks for immunocompetent adults
  • Only if severe pain and with antiviral treatment

Patient Advice

Infection Control

  • Infectious until all vesicles crusted over (5-7 days)
  • Avoid contact with susceptible people:
    • Pregnant women
    • Immunocompromised people
    • Babies younger than 1 month
    • Those who haven't had chickenpox/vaccine
  • Avoid sharing clothes and towels
  • Wash hands often

Symptom Management

  • Wear loose-fitting clothes
  • Cover weeping lesions not under clothes
  • Avoid topical creams and adhesive dressings
  • Keep rash clean and dry
  • Seek medical advice if fever develops (bacterial infection)
  • Avoid work/school if weeping rash cannot be covered

Complications

Vaccination Programme

A shingles vaccination programme was introduced in September 2013 to reduce incidence and severity in adults aged 70 years and older, who are at higher risk of post-herpetic neuralgia.

Common Complications

  • Post-herpetic neuralgia: Pain persisting >90 days after rash (most common)
  • Skin changes: Scarring, pigmentation changes, keloid formation
  • Superinfection: Secondary bacterial infection (staphylococcal/streptococcal)
    • Cellulitis
    • Osteomyelitis
    • Necrotising fasciitis
    • Sepsis

Neurological Complications

  • Herpes zoster oticus (Ramsay Hunt syndrome):
    • Facial nerve infection (cranial nerve VII)
    • Ear lesions, facial paralysis
    • Hearing and vestibular symptoms
  • Herpes zoster ophthalmicus:
    • Ophthalmic division of trigeminal nerve
    • Keratitis, corneal ulceration, conjunctivitis
    • Optic neuritis, retinitis, glaucoma, blindness
  • Peripheral motor neuropathy: Loss of movement
  • CNS complications: Encephalitis, meningoencephalitis, myelitis, cerebellitis, cerebrovascular disease, radiculitis, Guillain-Barré syndrome

Other Complications

  • Cardiovascular: Independent risk factor for stroke, TIA, myocardial infarction
  • Systemic dissemination: Rare but serious
    • Pneumonia, hepatitis, encephalitis
    • Disseminated intravascular coagulopathy