The rash of HZ is preceded by a prodromal pahse.
- occurs 1-5 days before the onset of the rash (in 70-80% of patients)
- symptoms are usually non specific and may include:
- malaise
- headache
- photophobia
- abnormal skin sensations
- may range from itching and burning to hyperesthesia and severe pain.
- depending on the location and severity, pain may be mistaken for myocardial infarction, biliary or renal colic, pleurisy, dental pain, glaucoma, duodenal ulcer, or appendicitis, leading to misdiagnosis and potentially mistreatment
- in rare instances, the nerve pain is not accompanied by a skin eruption, a condition known as zoster sine herpete (3)
- occasionally fever.
Classically, the eruptions are present as grouped vesicles on an erythematous background.
- the rash begins as macules and papules, which evolve into vesicles and then pustules. Crusting of the lesions occur after 5-7 days
- usually affects a single dermatome and is unilateral
- most frequently involved ones are:
- thoracic – 55%
- trigeminal – 20%
- lumbar – 13% c
- cervical - 11%
- with increasing age more cranial lesions, including ophthalmic, and less involvement of the chest are observed
- a few scattered lesion may be seen outside the affected dermatome in nonimmunocompromised patients (2,3,4)
Along with eruption, patients experience dermatomal pain caused by acute neuritis. Pain may be divided into 3 distinguishable phases: acute pain phase (up to 30 days), subacute pain phase (30–90 days after rash healing) and post herpetic neuralgia (PHN, pain for more than 90 days after the onset of rash). Patients may complain of
- paresthesias - e.g. - burning and tingling
- dysesthesia - altered or painful sensitivity to touch
- allodynia - pain associated with nonpainful stimuli
- hyperesthesia - exaggerated or prolonged response to pain (3)
Additional features present in HZ include:
- pruritus
- local lymphadenopathy
Disseminated HZ occurs primarily in immunocompromised patients; it usually presents with a dermatomal eruption followed by dissemination but may also present with a diffuse varicella-like eruption (5)
- systemic dissemination may accompany the skin changes with involvement of the lung, liver, and brain
- visceral dissemination is associated with a mortality rate of 5% to 15%, with most deaths attributable to pneumonia
- neurologic complications of HZ may include acute or chronic encephalitis, myelitis, aseptic meningitis, polyradiculitis, retinitis, autonomic dysfunction, motor neuropathies, Guillain-Barre syndrome, hemiparesis, and cranial or peripheral nerve palsies
- more common complications include bacterial superinfection by Staphylococcus aureus or Streptococcus pyogenes, scarring, and hyperpigmentation.
Herpes zoster lesions contain high concentrations of VZV, which can be spread by contact and by the airborne route and which can cause primary varicella in exposed, susceptible persons. Less contagious than primary varicella, HZ is only contagious after the rash appears and until the lesions crust. Risk of transmission is reduced further if lesions are covered
- N.B. Shingles is not as infectious as chicken pox; but people who have not had chicken pox may get chicken pox as a result of contact with a person with shingles.
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