Herpes zoster (HZ), also known as shingles, is caused by the reactivation of the varicella-zoster virus.
Varicella-zoster virus is transmitted by droplet spread. It is a primary infection, usually developing in children younger than 15, commonly known as chickenpox. The disease is usually mild and initial symptoms like fever, malaise, conjunctivitis quickly pass and then small blisters appear on the trunk, head, proximal and distal parts of the arms and legs. Lesions are accompanied by a strong itching sensation. Over time, they turn into scabs, which fall off after a few days, leaving slight recessed scars. After the primary infection, Herpes zoster passes into the spinal ganglia and remains there in a latent, inactive state throughout life. When the immunity weakens, after a stronger emotional stress, intense physical exertion, use of immunosuppressive drugs or the presence of malignant diseases, the virus can reactivate causing typical skin lesions.
There are cases of children who developed herpes zoster infection after receiving a chickenpox vaccine.
How is herpes zoster recognised?
The appearance of skin lesions is usually preceded by unilateral intense pain, so-called prodromal neuralgia on one side of the body, most often in the region of the intercostal spaces or the lumbar part of the back. The pain can be so strong that it resembles the attack of renal colic. Sometimes there are also sensations of itching, numbness, increased sensitivity of the skin or tingling. After a couple of days, redness with or without swelling will appear in the same area with clustered smaller or larger blisters.
The contents of the blisters will become darker over time, and then hemorrhagic crusts are formed. After they fall off, the scars will remain present. The most common complication of Herpes zoster is postherpetic neuralgia. It is an inflammation of the nerve fibers, manifested by severe pain or burning, tingling or numbness of the affected part of the skin. The problems can endure up to six months after skin lesions resolve and are quite resistant to therapy. If the ophthalmic nerve is affected by infection, the so-called herpes zosterophthalmicus develops, which can lead to keratitis and eye complications. When the auditory nerve is affected, it can cause hearing loss, ear pain with or without dizziness.
Facial nerve paralysis is rarely observed.
Herpes zoster — How it is diagnosed?
The diagnosis is usually made based on anamnestic data and unilateral localisation of typical skin lesions.
When it comes to laboratory testing, Tzanck smear, PCR or DFA (Direct fluorescent antibody) can be used.
How is Herpes zoster treated?
Treatment of Herpes zoster involves the use of local and systemic drugs. Apart from dermatologists, a treatment is often prescribed also by ophthalmologists and neurologists. It is optimal if treatment is started within 72h of the appearance of skin lesions.
In systemic therapy, Acyclovir800 mg /daily for 7 to 10 days is prescribed; Famciclovir 500 mg 3 times daily for 7 days or Valaciclovir1 g 3 times daily for 7 days. When it comes to topical preparations, it is recommended to use antiseptics, desiccant agents, as well as antibiotic ointments in case of development of secondary bacterial infection. Postherpetic neuralgia can be treated with low doses of tricyclic antidepressants; antiepileptics — Gabapentin, Pregabalin; short-term administration of systemic corticosteroids; use of 8% Capsaicin patch and/or local anaesthetics.