Shingles is a disease caused by the varicella zoster virus (VZV). It results in painful, burning skin lesions of distinct pattern. VZV is also implicated as the virus that causes chickenpox. In fact, everyone who has had chickenpox is at risk for shingles.
Shingles is due to reactivation of VZV, which lay dormant in the individual since their childhood episode of chickenpox. Shingles generally occurs in older populations or in patients, whose immune systems are compromised.
The pathophysiology of shingles consists of latency and activation. After the human host has contracted the chickenpox, VZV remains dormant in the dorsal root ganglion (a sensory component of the central nervous system) for many years. This state of dormancy is considered the latent stage where the individual’s immune system keeps the virus from manifesting into shingles.
A broad humoral and cellular immune response prevents active disease; however, T cell-mediated-immunity (TCMI) in the nervous system is thought to play the most important role preventing shingles. TCMI is the immune system’s way of retaining memory of the first varicella zoster virus during the chickenpox. It reacts in a stronger and more rapid fashion against VZV, therefore preventing its activation into shingles. With this memory, the immune system is able to control against reactivation of the virus.
Unfortunately, once the immune system weakens as a result of age, cancer, or HIV infection, TCMI loses control of VZV and the virus activates. The most common presentation of VZV includes shingles, which consists of painful lesions along the skin in a unique, dermatome pattern. Prior to the eruption of these lesions, persons may experience a prodromal period of pain without lesions, numbness and tingling, or even itching.
Persons with shingles are also at risk of meningitis, peripheral facial nerve weakness and deafness, or secondary bacterial skin infection. It has been shown that Thymic Protein A may support the immune system by improving T-cell maturation to help fight shingles and other infections.