Herpes zoster, commonly known as shingles, is a reactivation of the varicella zoster virus, or chicken pox. Shingles in essence is a reoccurrence of this original chickenpox, but at a later time.  This happens because the varicella zoster virus lies dormant in the spinal cord nerves until something triggers a reactivation.  Triggering a reactivation is usually due to a decrease in cellular immunity.  This can occur as we age, are subjected to stress, or occur by the body’s exposure to syndromes and medications that result in decreased immunity. 

Shingles is characterized by painful vesicular rash, featuring small blisters on the skin.  This rash is usually restricted to a horizontal band around the torso.   Each horizontal band, or dermatome is supplied by a single spinal nerve.  As such, the nerve that experiences the reactivation of chickenpox is going to dictate the segment of the body that is affected and breaks out in pox-like rash.  Shingles usually has a benign course, but in rare cases the infection can spread.   

What are the phases of shingles?

Shingles occurs in 3 main phases which are described below:

Pre-eruptive phase:

This phase is characterized by unusual skin sensation or pain within the affected dermatome.  Blisters or lesions start to appear on the set dermatome between 48-72 hours.  There is slight pain, but you could experience other symptoms like muscle aches, headache, and rarely a fever.

Acute eruptive phase:

In this phase, there is an emergence of what looks like blistering on top of red irritated skin.  During this phase the skin blisters will rupture and eventually crust over becoming dry and flaky.  This is when most adults experience pain and discomfort.  It is important to note that until all blisters have dried over, those with shingles are contagious and can spread the varicella virus.  So you should avoid people that have not had the chicken pox, or are immunosuppressed.   Shingles tends to resolve within 2 weeks of this phase, but can sometimes take up to a month to clear up.

Chronic phase:

This is the most common complication of shingles.  It is characterized as persistent or recurring pain in the affected area.  Most people report a deep burning or aching pain, or electric shock–like pains. It can take an extended period of time for this pain to resolve.