Pain is the preliminary sign of herpes zoster. Few days later, skin rashes develop only on one side of the body affecting one or more skin dermatomes. In many cases, the rash develops on the left or right side of the torso. However, many individuals may develop the rash on one side of the neck or face or around the eyes. In addition to these, other signs and symptoms of herpes zoster include the following [7]:

• Burning accompanied by tingling sensation in the affected area
• Pruritic rashes 
• Skin rash with blisters that break and develop crust
• Individuals with herpes zoster also suffer from fever, fatigue and headache

Physical examination of the skin rashes and its characteristics forms the basis of the diagnosis. In addition, history of pain and the appearance of rash on one side of the body confirm herpes zoster. In many instances, tissue scrapings can be cultured for the virus, but such a kind of method is time consuming and delays diagnosis and consequent initiation of treatment.

Laboratory tests are of no importance in diagnosing herpes zoster. Also, no type of imaging studies is indicated in diagnosis of the condition. However, MRI can be carried out in cases when there is development of encephalopathy and myelopathy.

Herpes zoster cannot be cured; the symptoms can however be managed with antiviral drugs. These medications also reduce the risk of developing complications. Antiviral drugs such as famciclovir, valacyclovir and acyclovir are prescribed for effective management of the rash and blisters [8].

Along with antiviral drugs, numbing agents such as lidociane are also given in form of cream or gel to be applied on the affected area. In order to control the associated symptoms of herpes zoster, steroid injections can also be administered to shorten the duration of the episode [9].

The prognosis of the disease condition is extremely favorable with the rash that resolves within 10 to 15 days. Children and otherwise healthy individuals have a better prognosis as compared to the elderly population [5]. However, if treatment is not initiated in right time, it can cause debilitating and life threatening complications in the immunocompromised population [6].

The virus known as varicella zoster virus (VZV) causes herpes zoster. The VZV virus belongs to the Herpesviridae family. The exact etiology that causes the reactivation of the virus years after initial exposure is not yet known. However, individuals with poor immunity status are known to fall easy prey to this disease. Certain disease conditions such as HIV and cancer can predispose the individual to develop herpes zoster [2].

It has been estimated that in the US, about 99.5% adult aged 40 years and above are susceptible to reactivation of VZV. An individual of any age group who has suffered varicella early in life is susceptible to develop herpes zoster as they age. It happens probably because of lowered immunity. It has also been reported that, individuals who have suffered an attack of herpes zoster are at an increased risk of developing another attack of the disease later in the life. About 4% individuals are susceptible to develop recurrent attacks of herpes zoster [3].

The causative organism varicella zoster virus causes two discrete disease conditions, varicella and herpes zoster. Herpes zoster majorly occurs in those individuals who have suffered varicella early in their life. It is not a contagious disease, but individuals can pass on the virus to healthy individuals. As a result, the healthy individual would develop varicella and not herpes zoster.

After an episode of varicella, the virus remains in dormant state in the dorsal root ganglion. An attack of herpes zoster occurs, when the virus gets activated for reasons not clearly understood. However, certain factors such as decreased immunity or stress are known to predispose an individual to develop herpes zoster [4].

Herpes zoster can be prevented through vaccines namely varicella vaccine and varicella–zoster vaccine. The varicella vaccine used for prevention against chicken pox is now commonly used for children. This vaccine is also recommended for adults also who have never had chicken pox.

The FDA has approved the use of varicella–zoster vaccine for individuals aged 50 years and above. This vaccine significantly decreases the likelihood that individuals would develop herpes zoster. However, this vaccine is not indicated for individuals with weakened immune system [10].

An episode of herpes zoster is short lived and manifests as skin rashes in children and adults. Individuals who have suffered from varicella (chicken pox) can develop herpes zoster later in life. Once varicella is treated, the virus stays in dormant state inside the body and is not eliminated. Years after the initial exposure, the virus often causes episodes of herpes zoster [1].

Definition

Herpes zoster is a viral infection characterized by development of skin rashes with blisters specifically on one side of the body. The rash is confined to a small portion and appears as a single strap of blisters.

Cause

The virus known as varicella zoster virus causes herpes zoster. Individuals who had suffered from chicken pox early in their life are more prone to develop herpes zoster. The virus stays in dormant state in the body and gets activated when it gets favorable environment to grow. Individuals with poor immunity profile are at an increased risk of developing herpes zoster.

Symptoms

Individuals with herpes zoster develop painful rash along with blisters on one side of the body. In addition, certain percentage of affected population may also experience fever along with general weakness.

Diagnosis

No laboratory studies or imaging tests are useful in diagnosis of herpes zoster. Careful physical examination of the skin rashes and its characteristics helps in establishing a definite diagnosis of the condition.

Treatment

Antiviral agents along with corticosteroids are administered for treatment of herpes zoster. For providing relief from the uncomfortable symptoms of the rashes, numbing agents such as lidocaine are also given to be applied on the affected area.

1. Karlin JD. Herpes zoster ophthalmicus: the virus strikes back. Ann Ophthalmol. Jun 1993;25(6):208-15.
2. Whitley RJ, Weiss HL, Soong SJ, Gnann JW. Herpes zoster: risk categories for persistent pain. J Infect Dis 1999; 179:9.
3. Wung PK, Holbrook JT, Hoffman GS, Tibbs AK, Specks U, et al. Herpes zoster in immunocompromised patients: incidence, timing, and risk factors. Am J Med. Dec 2005;118(12):1416.
4. Gnann JW Jr, Whitley RJ. Clinical practice. Herpes zoster. N Engl J Med 2002; 347:340.
5. Tseng HF, Chi M, Smith N, et al. Herpes zoster vaccine and the incidence of recurrent herpes zoster in an immunocompetent elderly population. J Infect Dis 2012; 206:190.
6. Schmader K, George LK, Burchett BM, Pieper CF. Racial and psychosocial risk factors for herpes zoster in the elderly. J Infect Dis. Nov 1998;178 Suppl 1:S67-70.
7. Dolin R, Reichman RC, Mazur MH, Whitley RJ. NIH conference. Herpes zoster-varicella infections in immunosuppressed patients. Ann Intern Med 1978; 89:375.
8. Wood MJ, Shukla S, Fiddian AP, Crooks RJ. Treatment of acute herpes zoster: effect of early (< 48 h) versus late (48-72 h) therapy with acyclovir and valaciclovir on prolonged pain. J Infect Dis. Nov 1998;178 Suppl 1:S81-4.
9. Fernandes NF, Malliah R, Stitik TP, Rozdeba P, Lambert WC, Schwartz RA. Herpes zoster following intra-articular corticosteroid injection. Acta Dermatovenerol Alp Panonica Adriat. Mar 2009;18(1):28-30.
10. Oxman MN, Levin MJ, Johnson GR, et al. A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults. N Engl J Med 2005; 352:2271.