Read more about this disease, some with Classification – Types – Signs and symptoms – Genetics – Pathophysiology – Diagnosis – Screening – Prevention – Treatment and management – Cures and much more, some including pictures and video when available.
Herpes zoster (or simply zoster), commonly known as shingles, is a viral disease characterized by a painful skin rash with blisters in a limited area on one side of the body, often in a stripe. The initial infection with varicella zoster virus (VZV) causes the acute (short-lived) illness chickenpox, and generally occurs in children and young people. Once an episode of chickenpox has resolved, the virus is not eliminated from the body but can go on to cause shingles—an illness with very different symptoms—often many years after the initial infection.
Varicella zoster virus can become latent in the nerve cell bodies and less frequently in non-neuronal satellite cells of dorsal root, cranial nerve or autonomic ganglion,[1] without causing any symptoms.[2] In an immunocompromised individual, perhaps years or decades after a chickenpox infection, the virus may break out of nerve cell bodies and travel down nerve axons to cause viral infection of the skin in the region of the nerve. The virus may spread from one or more ganglia along nerves of an affected segment and infect the corresponding dermatome (an area of skin supplied by one spinal nerve) causing a painful rash.[3][4] Although the rash usually heals within two to four weeks, some sufferers experience residual nerve pain for months or years, a condition called postherpetic neuralgia. Exactly how the virus remains latent in the body, and subsequently re-activates is not understood.[1]
Throughout the world the incidence rate of herpes zoster every year ranges from 1.2 to 3.4 cases per 1,000 healthy individuals, increasing to 3.9–11.8 per year per 1,000 individuals among those older than 65 years.[5][6][7] Antiviral drug treatment can reduce the severity and duration of herpes zoster, if a seven to ten day course of these drugs is started within 72 hours of the appearance of the characteristic rash.[5][8]
The earliest symptoms of herpes zoster, which include headache, fever, and malaise, are nonspecific, and may result in an incorrect diagnosis.[9][5] These symptoms are commonly followed by sensations of burning pain, itching, hyperesthesia (oversensitivity), or paresthesia (“pins and needles”: tingling, pricking, or numbness).[10] The pain may be extreme in the affected dermatome, with sensations that are often described as stinging, tingling, aching, numbing or throbbing, and can be interspersed with quick stabs of agonizing pain.[11] In most cases, after 1–2 days (but sometimes as long as 3 weeks) the initial phase is followed by the appearance of the characteristic skin rash. The pain and rash most commonly occurs on the torso, but can appear on the face, eyes or other parts of the body. At first, the rash appears similar to the first appearance of hives; however, unlike hives, herpes zoster causes skin changes limited to a dermatome, normally resulting in a stripe or belt-like pattern that is limited to one side of the body and does not cross the midline.[10] Zoster sine herpete describes a patient who has all of the symptoms of herpes zoster except this characteristic rash.[12]
Later, the rash becomes vesicular, forming small blisters filled with a serous exudate, as the fever and general malaise continue. The painful vesicles eventually become cloudy or darkened as they fill with blood, crust over within seven to ten days, and usually the crusts fall off and the skin heals: but sometimes after severe blistering, scarring and discolored skin remain.[10]
Herpes zoster may have additional symptoms, depending on the dermatome involved. Herpes zoster ophthalmicus involves the orbit of the eye and occurs in approximately 10–25% of cases. It is caused by the virus reactivating in the ophthalmic division of the trigeminal nerve. In a few patients, symptoms may include conjunctivitis, keratitis, uveitis, and optic nerve palsies that can sometimes cause chronic ocular inflammation, loss of vision, and debilitating pain.[13] Herpes zoster oticus, also known as Ramsay Hunt syndrome type II, involves the ear. It is thought to result from the virus spreading from the facial nerve to the vestibulocochlear nerve. Symptoms include hearing loss and vertigo (rotational dizziness).[1]
If the rash has appeared, identifying this disease (making a differential diagnosis) only requires a visual examination, since very few diseases produce a rash in a dermatomal pattern (see map). However, herpes simplex virus (HSV) can occasionally produce a rash in such a pattern. The Tsanck smear is helpful for diagnosing acute infection with a herpes virus, but does not distinguish between HSV and VZV.[14]
When the rash is absent (early or late in the disease, or in the case of zoster sine herpete), herpes zoster can be difficult to diagnose.[15] Apart from the rash, most symptoms can occur also in other conditions.
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