Bug of the Month – Shingles
Shingles (herpes zoster) is a painful, blistering skin rash caused by the Varicella zoster virus – the same virus that causes chickenpox. After a person recovers from chickenpox, the virus moves into the spinal nerves and becomes dormant. When the immune system (cellular immunity) declines with age the virus can reactivate. Other conditions which depress cellular immunity put patients at increased risk for shingles (herpes zoster). Those include patients with hematologic malignancies (leukemia and lymphomas), HIV infection, and medical interventions such as chemotherapy, high-dose steroid therapy, immunosuppressive therapies.
Distribution of the outbreak is based on nerve pathways at the site of virus latency. When Varicella replicates in the skin during an episode of chickenpox, the virus tracks along sensory nerves to the skin -- from the skin back to the nerve ganglia -- and establishes latency in those nerve root ganglia. There it sits for many decades. When the immune system begins to decline either from age or other immunity depressive situations, the virus is able to reactivate, and follow that same nerve root back out to the skin, causing vesicles in that limited distribution that we recognize as herpes zoster: a band-like distribution of lesions corresponding to the distribution of a single sensory nerve root. This is an important diagnostic feature of herpes zoster.
The distribution of the blistered rash always corresponds to the distribution of a single band of skin that receives sensations through a single major nerve branch (dermatome). The blisters can be scattered in patches or form a continuous band, and they look a lot like chicken pox. The blisters break, forming small ulcers that begin to dry and form crusts. The crusts fall off in 2 to 3 weeks. Scarring is rare. The rash usually involves a narrow area from the spine around to the front of the belly area or chest. The rash may involve face, eyes, mouth, and ears. The blisters can be mildly irritating, itchy, or intensely painful. The rash and blisters from shingles almost always occur on just one side of the body. Shingles may appear on the following areas of the body:
- One side of the torso
- One side of the face
Disseminated herpes zoster is defined as more than twenty skin lesions outside the affected dermatome; but other organs, such as the liver, central nervous system, lungs, and pancreas. The condition may be life-threatening and is more likely to occur in immunocompromised patients rather than the general population.
Use Standard Precautions for patients who have an intact immune system and whose lesions can be covered. Airborne Precautions are required for any patient with disseminated disease and for localized disease in immunocompromised patients until disseminated infection is ruled out.
If you would like additional information please call Infection Prevention and Control at 543-2280.