What is Shingles and can it Spread to cause Chicken Pox in others?

Chicken Pox & Herpes Zoster are two diseases caused by the same Virus

Varicella Zoster is a very common virus that affects human beings in two different forms at two different periods of their life. The far more common manifestation of this viral infection is Chicken Pox , usually in childhood. The virus, however, can survive in the body and later cause another disease, Herpes Zoster or Shingles. This is a unique infectious disease since it arises from an infection several years ago. However, it also gives rise to doubts and confusion about the contagious nature of infection, and the period when the virus is most likely to spread from a patient.

The band like spread of skin rash associated with pain and abnormal sensations is characteristic of Herpes Zoster or Shingles

What is Shingles?

Herpes Zoster or Shingles is a very painful condition caused by the Varicella-Zoster virus, which manifests with skin rashes, usually limited to a particular area of the body. It is commonly seen in later part of life or during old age, usually in periods of stress that disturbs the immunity of the body to hold the virus in check.

What are the Signs & Symptoms of Shingles?

The initial symptoms in Shingles are similar to that of influenza or flu and consist of fatigue, fever, headache, body aches. In some cases there can also be sudden chills or disturbances of stomach and digestive system.

These initial symptoms of generalised illness are followed two to five days later by more specific symptoms that include irritation, unpleasant sensations, itching and pain. These sensations are typically felt in an area supplied by a particular nerve, or a group of nerves with common origin. The patient usually experiences small painful rash, which may enlarge in some cases to form blisters in the affected area. This combination of abnormal sensation, pain and skin rashes limited to an area in a particular nerve distribution is the most characteristic feature of Shingles.

The sites most commonly affected in Shingles are the side of abdomen and back, commonly spread in the form of a horizontal band like distribution spreading across from the centre to the flanks. Another common site affected by Shingles is one half of the upper face that may also include the eye. Pain is also limited to that same affected area and can vary from dull, gnawing ache to episodes of sharp, stabbing pain.

With passage of time, the blisters gradually soften up as the skin around them becomes reddish and inflamed. New blisters may keep on appearing in Shingles for up to a week.

After a week or so, the blisters either begin to open up, or begin to dry. In both cases, they are converted to dry crusts or scabs which gradually disappear after some time, leaving slight scars in some cases, at the affected sites.

Most often, the pain of Shingles completely subsides completely after some time. However, in sometimes, pain may continue to exist even after the rash and blisters have completely disappeared, giving rise to a condition that is known as “Post Herpetic Neuralgia”.

How is Shingles related to Chicken Pox?

Both Shingles and Chicken Pox are caused not only by the same virus, but very often by the same infection of the Varicella Zoster virus. Actually, the first clinical manifestation of this infection is Chicken Pox and not Shingles. It is also a fact that Chicken Pox is a far more common disease caused by this virus. Comparatively, only a small proportion of those who develop Chicken Pox on getting infection develop Shingles in later life.

What is Chicken Pox?

Chicken Pox is a common viral rash, caused by the Varicella Zoster virus, which affects a large number of people, commonly in childhood. It is caused by the same virus infection that also causes Shingles in later life.

Is Chicken Pox Contagious?

Chicken Pox is characterised by fever, itching and skin rash or fluid filled blisters that are self limited and usually subside in a week or two. It is a contagious disease, which can be transmitted by air as well through physical contact with the patient. The Varicella Zoster virus has the ability to spread from the patient to infect another person through air, by droplets formed from sneezing and coughing of the patient. It can also spread from direct physical contact involving blister fluids or drying crusts. Chicken Pox is highly contagious and the virus begins to spread from an infected person even before the symptoms appear, which is the reason of its high prevalence among children.

Can patient of Chicken Pox have Chicken Pox once again?

Chicken Pox is a self limited disease. It resolves and subsides due to the development of immunity in the affected patient, which keeps the virus at bay, and prevents it from causing the disease again. The symptoms of Chicken Pox arise in an infected person around three weeks after the infection with Varicella Zoster virus. They subside in a week or two and thereafter the infected person becomes absolutely normal. Thus, Chicken Pox is usually once in a lifetime disease. In other words, a person getting Chicken Pox develops a lifetime immunity against a recurrence of Chicken Pox.

Can a patient of Chicken Pox have Shingles Later on?

The immunity developed by a patient of Chicken Pox can keep the Varicell Zoster virus at bay and prevent it from causing any recurrence of Chicken Pox subsequently. However, the virus is not completely eliminated from the body. It continues to survive in the neural cells of the spine in a dormant form, and can do so for the rest for one’s life. In most such cases, the Varicella Zoster virus continues to remain fully inactive throughout the life of the patient of Chicken Pox. However, in a minority of such cases, it can become reactivated again, this time, lead to a different disease called Herpres Zoster or Shingles.  

Thus, Shingles always happens in persons who have had Chicken Pox at some point of time earlier in their life. In some cases, particularly those who have received the Varicella Vaccine, the disease (Chicken Pox) might have taken a very mild form that may have subsided without being detected as Chicken Pox. Even these persons are still prone to have Shingles later in life.

Since the surviving Varicella Zoster virus is held at bay by the immunity of the body, it is commonly a fall in this body immunity that allows the virus to get activated once again. Accordingly, the reactivation of dormant Varicella Zoster virus within the body is often associated with a fall in body immunity, as in cases of physical or emotional stress, other illnesses,  AIDS, cancers or treatment with immune suppressive medication.

Is Shingles Contagious ?

This is a common and somewhat tricky question to answer, since the virus causing Shingles does spread and cause infections in another person, a process that we usually associate with a contagious disease. However, the disease that the virus causes in others immediately, is not Shingles, but Chicken Pox, though the same infection can resurge in the form of Shingles several years later.

It needs to be appreciated that is the Varicella Zoster virus that spreads from one person to another and that the diseases, both Shingles and Chicken Pox are only the clinical manifestations of that infection.

The Varicella Zoster virus causes not one, but two diseases, Chicken Pox and Shingles, and can spread from a patient of either of these conditions to another. In Chicken Pox, it spreads through both the physical contact with blisters as well as through air (as it is present in respiratory tract of Chicken Pox patients and spreads through their sneezing, coughing etc). In a case of Shingles, however, it can spread only through direct contact with blisters fluid and crusts, and generally not through air. Varicella Zoster is also known to be present in the saliva of the infected person, but there is not enough evidence to conclude if it does spread by kissing.

How Long can Shingles be Contagious & who can be affected by it?

Shingles can be contagious since Varicella Zoster virus can spread from a patient of Shingles to an uninfected person who comes in contact with blisters. The contagious period coincides with the onset of blisters and continues till the Shingles blisters completely scab and disappear. In most cases, it will lead to Chicken Pox.

As one would expect, it is children who have never been infected with this virus earlier that are the most vulnerable to its spread. Physical contact, directly or through towels, linen etc. with a person suffering from Shingles and having blisters can spread the Varicella Zoster virus to those who have never been infected, especially children, and may cause Chicken Pox in them, around three weeks after the infection. In same persons, Shingles may also happen, though not necessarily, after a gap of several decades.

However, contact with a person with Shingles will not affect those who have already been affected with Chicken Pox as they are immune to Varicella Zoster virus and may actually be harbouring the same virus inside their own bodies. Thus, those who have been affected with Chicken Pox earlier in their life have little to fear from the contagious nature of Shingles.

Shingles & Chicken Pox: One Virus, One Infection, but Two Diseases

Thus, Shingles does not spread from one person to another like other contagious diseases, even though the Varicella Zoster virus can spread from a person suffering from Shingles to an uninfected person, leading to Chicken Pox a few weeks after infection, and possibly Shingles too, after a gap of several decades. Since most of the people are already infected with the virus (and already had Chicken Pox), Shingles is not contagious for them.

What Precautions can be taken to Avoid Spread of Virus Infection?

Shingles patient are a far less important source of spread of Varicella Zoster virus, simply because patients of Chicken Pox, which are also far more common, spread it far more aggressively, through air transmission and without requiring any physical contact. This transmission of virus begins even before they begin to exhibit any symptoms or the disease is identified in them. This is the main reason why it is very difficult to control the spread of Chicken Pox in society.

However, a Shingles patient should still take all necessary precautions to ensure that he does not spread the virus to others who are not infected. It is preferable to rest indoors and avoid social activities that involve physical contact, in particular, with children who can be more vulnerable. Some of the other precautions include covering the blisters with non-adhesive dressing, which can prevent contagious spread of the virus, and should be resorted to by those who still have blisters but who wish to work or enjoy social activities. Till blisters completely disappear, one must stay away from community swimming pools, contact sports like Rugby and avoid sharing towels, linen, bedding etc. with those who might be uninfected, especially children or young adults.