Shingles

Key Points

Better known as shingles
Painful skin rash that often forms blisters
Occurs in a dermatome(sensory nerve distribution) on one side of the body...does not cross the midline
Viral in nature, caused by the chicken pox virus (varicella-zoster virus=VZV)

Herpes Zoster, often known as shingles, is a frequently painful skin rash localized to one region of the body. The herpes zoster virus (VZV) is the same virus that causes chicken pox (varicella). Once an outbreak of chicken pox has resolved, the virus becomes dormant in the sensory nerve root along the spinal cord. The area where it remains dormant is called the dorsal root ganglion. Later in life, the virus may reactivate and travel along the nerve, often causing severe pain and in a region of the body. Because individual sensory nerves are responsible for sensation in one region on one side of the body, the associated pain and eventual blisters are confined to that region. The resulting skin rash — which is often accompanied by clear or bloody blisters — occurs most often in people over the age of 60, although certain diseases like AIDS or cancer can suppress the immune system enough so that the herpes zoster virus can reactivate. Aging, illness or stress to the body or mind may tigger herpes zoster.

Patients with zoster are contagious and should avoid immunosuppressed people, pregnant women, and people that have not had chicken pox. Once all of the sores from a zoster outbreak have scabbed, the patient is no longer contagious.

Herpes zoster ophthalmicus occurs when VZV infects the first branch of the trigeminal nerve, V1. This nerve innervates the forehead, nose and eye. Infection of this region can lead to severe eye pain, conjunctivitis, and vision loss. Hutchinson's sign describes blister involvement of the nasal tip, sidewall or nasal root. The presence of this sign is a predictor of more severe ocular involvement with likelihood of a worse outcome concerning vision loss and disease severity.

Herpes zoster oticus (Ramsay Hunt Syndrome) describes VZV affecting the V3 branch of the trigeminal nerve. This nerve innervates the ear and lower jaw line. Complications of infection in this region include: blistering rash, severe ear pain, hearing loss, and paralysis of the facial nerve.

Differential Diagnosis (Other conditions with similar appearance)Conjunctivitis

Coxsackievirus
Superficial pyoderma

Diagnosis

Key Points

Starts as a tingling or burning localized pain
Rash appears 2-3 days later
Blisters break and form crusts
Rash is almost always unilateral, with the blisters only on one side of the body, thus not crossing the “midline” of the body. The severely immunosuppressed are an exception and are at risk for disseminated (widespread) herpes zoster

Herpes zoster usually begins as a one-sided tingling or burning pain, which may actually become quite severe before the rash appears. When this occurs on the left side of the chest, it is sometimes mistaken for a heart attack. Red patches will subsequently form two to three days later, often with blisters (initially, it looks like hives). Once the blisters break, ulcers dry out and form crusts, which normally fall off in two to three weeks. The rash usually occurs anywhere from the spine to the front of the belly, though it can involve the face, mouth, eyes, or ears. Additional symptoms may include abdominal pain, chills, fever, joint pain, taste and vision problems, headaches or even loss of eye motion or a drooping eye. Forehead or eyelid involvement especially with nasal tip blisters warrants immediate therapy and evaluation by ophthalmology.

Once the rash has appeared, a dermatologist can recognize herpes zoster by sight. Lab tests can confirm the diagnosis.

Treatment

Because shingles usually resolves itself, treatment is not absolutely required, but early treatment may reduce the likelihood of long term pain. Pain is uncommon once the rash has disappeared for people under age 50. However, the older the patient, the more severe the outbreak and the longer the delay in therapy, all increase the risk of post herpetic neuralgia. Over the counter analgesics or topical lotions with calamine are usually sufficient for mild pain. Early use of antiviral drugs may reduce the severity and duration of shingles and, importantly, decrease the risk of chronic pain in the region (post herpetic neuralgia). One in five sufferers of shingles will develop post-herpetic neuralgia, a pain in the area that could last for months or years, which results from damage to the nerves.

In extreme cases, shingles may also lead to blindness (if the shingles occur in the eyes), deafness, or secondary skin infection. Uncommonly, another occurrence of shingles may happen in the patient's lifetime.