Diagnosis is usually based on the clinical picture.
Antiviral medication should be considered case by case, particularly if less than 3 days have elapsed since the eruption of the rash.
Antiviral medication should always be started for patients with immunodeficiency, if the disease is located in the trigeminus area, if the patient is older (over 60) or if the clinical picture is severe.
Remember to ensure effective analgesic treatment of acute shingles pain and any postherpetic neuralgia.
Aetiology
Shingles, also known as herpes zoster, is caused by the varicella zoster virus (VZV) remaining in the paraspinal ganglia after a varicella infection.
Shingles represents reactivation of the virus.
Even people vaccinated against varicella may develop shingles.
Symptoms and findings
Clearly defined erythema usually confined to one side of the midline in the area of a single dermatome, with vesicles in linear formation.
A more extensive clinical picture, appearing in several dermatomes, is also possible.
Typically occurs on the trunk (particularly in dermatomes T1-L2 ) and the face (dermatomes V1-V3); more rarely on the extremities and in the genital area (Images 1234).
In 1-2 weeks, the vesicles turn into pustules with ulceration and crusting.
Mild general symptoms may occur, including fever, headaches, malaise and fatigue.
Acute shingles pain
Local skin pain may be constant or periodical.
Shooting pain (dysaesthesia) or tenderness to touch (allodynia, hyperalgesia) may begin several (2-3) days before the eruption of the rash.
Remember shingles in the differential diagnosis of chest, abdominal and back pain; always check the skin of patients with pain (Image 6).
Remember the possibility of immunosuppression particularly in patients with severe shingles or disease spreading beyond the boundaries of one dermatome.
Very rarely, patients may have only pain without a rash (zoster sine herpete).
The rash usually heals in about 2-4 weeks but scars may remain.
A patient with shingles is less likely to transmit the virus than a chickenpox patient.
It is recommended to avoid contact especially with people who belong to high-risk groups and who have not had chickenpox or chickenpox vaccination.
Young children
Pregnant women
Immunodeficiency states (e.g. immunosuppressive drugs, cancer and transplant patients)
Shingles contagiousness usually stops when skin lesions form scabs (about 1-2 weeks after the onset of symptoms).
Complications
Postherpetic neuralgia
Pain persisting after the rash has healed (usually subsides within 6 to 12 months but may in some cases continue for years)
People over 70 represent a particular risk group.
Eye complications if the ophthalmic nerve is affected
Keratitis, corneal ulceration and iritis, for example
The eye(s) is/are probably also affected if there is rash along the side of the nose (dermatome of the nasociliary nerve; Image 7).
May lead to permanent eye problems.
Absolute indications for urgent consultation of an ophthalmologist: the eye is clearly red, the sensation of the cornea is impaired when tested with a cotton wool probe or visual acuity is decreased.
Consultation of an ophthalmologist should not delay the start of antiviral medication.
Other complications
Secondary bacterial infection (cellulitis)
Peripheral nerve paralysis (e.g. facial palsy in patients with Ramsay Hunt syndrome (herpes zoster oticus) Peripheral Facial Paralysis)
Permanent nerve damage
Disseminated shingles
Encephalitis (usually in patients with immunodeficiency)
Workup
Diagnosis is usually based on the clinical picture.
In unclear cases, the virus should be detected on the skin or on the mucosa (nucleic acid detection).
Uncomplicated shingles will not usually elevate inflammatory markers (CRP, leukocytes) unlike erysipelas or cellulitis; in patients with shingles, CRP levels usually remain below 20-30 mg/l.
Differential diagnosis
Herpes simplex infection
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 a primary Herpes simplex infection.
A recurrent vesicular rash resembling shingles is very likely caused by Herpes simplex.
Acute eczemas Allergic Contact Dermatitis (acute allergic contact eczema, in particular): the main symptoms are itching, erythema and blisters, no fever
Impetigo Impetigo and other Pyoderma: usually few symptoms, may be asymmetric, patchy skin erosions covered with yellow crust
Erysipelas Erysipelas: hot, clearly defined erythema, possibly with blisters, usually fever, not that painful, not following the boundaries of dermatomes
Treatment started early (within 3 days from the eruption of the rash) will shorten the duration of the disease and may prevent complications (particularly eye complications and neuralgia) Antiviral Drugs for Preventing Postherpetic Neuralgia.
Antiviral medication should be considered case by case, particularly if fewer than 3 days have elapsed since the eruption of the rash.
Antiviral medication should always be started (also later in the course of the disease)
in immunosuppressed patients (severe systemic disease, poorly controlled diabetes, cancer, primary immunosuppression, HIV infection, or taking immunosuppressants, such as oral glucocorticoids)
in patients with trigeminal shingles (remember eye complications!)
N.B.: dose adjustment in patients with various degrees of renal failure
For patients with immunodeficiency, eye complications or slow response to treatment, the course of antiviral treatment may need to be extended to 2 to 3 weeks, for example.
For patients with immunodeficiency and a severe course of disease, hospital treatment and i.v. aciclovir (10 mg/kg 3 times daily) may be necessary.
Topical treatment
Antiviral ointments play no role in the treatment of shingles.
Topical treatments such as moist compresses and zinc paste, for instance, may alleviate the symptoms in the initial phase.
Antiseptic and antimicrobial creams have also been used (to prevent secondary bacterial infections).
In postherpetic neuralgia the pain is prolonged (continuing long after the skin changes have disappeared or continuing for more than 3 months, for example). It usually disappears in 6-12 months, but in the elderly, in particular, the neuralgia may last for years.
Paracetamol is the safer alternative in children and elderly persons.
A mild opioid (codeine, tramadol) may be added to the regimen, as necessary.
Topical treatment may help: a zinc ointment or paste, a cooling gel.
If the treatment response is poor in acute shingles pain, all medications intended for postherpetic neuralgia (such as amitriptyline or pregabalin, see below) have also been used to treat prolonged acute pain and for possible prevention of neuralgia.
Suitable especially for relatively young, otherwise healthy patients.
Contraindications: arrhythmias, urinary difficulties or orthostatic hypotension
Start with a small dose in the evening, 10-25 mg, for example, and increase the dose by 5-10 mg every few days until a good analgesic effect is reached or potential adverse effects prevent increasing the dose further (tiredness, dryness of mouth, constipation, urinary difficulties, orthostatic hypotension).
25-75 mg amitriptyline once daily, can be increased up to 100 mg once daily, in single doses in the evening
First 10-25 mg nortriptyline once daily, increased by 10-25 mg weekly to the target dose of 75-150 mg daily, in single doses or divided into 2 doses
Antiepileptic drugs
Pregabalin and gabapentin are first-line drugs for patients with contraindications to tricyclic antidepressants. These may, however, be strongly sedative.
Pregabalin starting at 75 mg twice daily and, if needed, increasing after 1-2 weeks to the dose 150 mg twice daily and thereafter, if needed, further up to the dose 300 mg twice daily
GabapentinGabapentin for Chronic Neuropathic Pain in Adults, starting at 300 mg in the evening and increasing the dosage in 300-mg steps at intervals of 1-3 days up to 3 600 mg daily, if needed. The daily dose should be taken in 3 divided doses.
The SNRIs duloxetine, initial dose (30-)60 mg once daily, or venlafaxine, initial dose (37.5-)75 mg once daily (no official indication, fewer anticholinergic adverse effects compared to tricyclic antidepressants)
May be a better and safer alternative compared with tricyclic antidepressants in elderly patients.
If the response to the above treatments is insufficient, treatments such as strong opioids at individual dosage and other modes of treatment of chronic pain (started usually in units with experience in the treatment of pain) can be considered.
Treatment in elderly persons
All the aforementioned drugs may usually be used, but the initial and maintenance doses are smaller.
In the elderly, the initial and maintenance doses are usually half that of people in working age (start, for example, with the lowest possible dose and increase dose slowly).
Potentially impaired kidney function must be taken into account.
SNRI drugs are the safest.
Tricyclic antidepressants have the strongest anticolinergic effects (confusion, memory impairment, urinary retention, constipation and worsening of glaucoma).
The sedative effect is strongest in antiepileptic drugs (pregabalin, gabapentin); remember the falling risk.
Recombinant vaccine (Shingrix® ) (2 doses at an interval of 2 months; does not contain live virus and hence can also be used in immunocompromized persons). Intended for people over 50 years of age with normal shingles risk and for people over 18 years of age with increased shingles risk.
Zostavax® contains attenuated live virus (single dose; not suitable for severely ill, immunocompromized persons). Intended for people over 50 years of age.
Specialist consultation
For patients with immunodeficiency or particularly severe disease, hospital treatment and initial treatment with i.v. aciclovir may be necessary.
In the case of postherpetic neuralgia that is difficult to manage consult specialized care, as necessary.
References
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