The family herpes – introducing chickenpox and shingles
We have all heard of herpes but may be unaware that there are three separate members in the same family and, whilst they share similar genetic material and have certain similarities, they are, like many members of the same family, completely individual and different.
Herpes zoster causes chickenpox and its secondary manifestation of shingles in later life.
Herpes simplex Type I normally causes cold sores and sometimes genital herpes.
Herpes simplex Type II causes genital herpes.
I came across a crew member recently who developed full-blown chickenpox for the first time after spending time with an affected child a couple of weeks previously. He had not had chickenpox and was therefore not immune and he developed the typical illness. It is not generally regarded as an occupational hazard of yachting but owners’ families and charter guests can bring children onboard and they may succumb to any of the common childhood ailments
Herpes are all viruses and therefore are not amenable to treatment by antibiotics like bacteria. Antibiotics vastly outnumber antivirals but the good news is that there are a few antivirals and one of the first on the market, available since 1982 (Nobel Prize for Medicine, 1988), was aciclovir (“Zovirax”) which is active against the nuclei of herpes viruses. This is one of the important similarities in the family and it opened up the door to more effective treatment of the conditions listed above.
The other similarity, which is not so welcome, is that infection is permanent. Once infected with any of the herpes viruses, the symptoms can keep recurring indefinitely.
This is illustrated by the herpes zoster virus which produces the familiar chickenpox infection, usually in childhood. The infection is spread by droplet inhalation rather like a cold and then the rash starts after a day or two of flu-like symptoms which resolve after about two weeks. The affected person is infective to others from the start of the flu-like symptoms until about ten days after the rash starts by which time the spots have turned to little scabs and are starting to fall off. The rash is notoriously itchy in the early stages and scratching can disturb the lesions and causearticles/article_42.htm permanent spot scars which do not tan. Aciclovir can ease the severity of the attack but is not generally given to children who normally make an uneventful recovery but adults can be more seriously ill especially if the virus causes pneumonia so they justify high dose oral aciclovir. It is very important that infected individuals remain as isolated as possible to avoid infecting others at risk, particularly those with chronic disease and reduced resistance who have never had the condition because they can become seriously unwell or die.
Once the acute episode has settled the virus remains in the body and lives permanently in the roots of spinal nerves. At some future date when, for example, the person is run down or suffering from some other illness, the virus can re-emerge along the track of one particular nerve and cause a chickenpox rash in the skin supplied by that particular nerve. This is shingles and accounts for the rash being very demarcated in a section of the body and only on one side of the body – the mirror image nerve on the opposite side remaining dormant. The rash can coalesce from the back to the front and form a half-circle “ring of fire”, so called because of the intense pain associated with herpes skin infection. The symptoms are reduced by high dose oral aciclovir taken as early as possible.
An episode of chickenpox confers immunity on the individual, although subsequent episodes have been recorded when the first attack was mild, but shingles remains a possible long term complication. There is a mild risk of catching chickenpox from shingles and this is much more likely amongst patients who are ill in hospital, perhaps on immunosuppressive or cytotoxic therapy – staff in these units are required to stay home. There is no chance of catching shingles from shingles because it is a secondary manifestation of chickenpox and therefore the individual needs to have chickenpox first and then maybe develop shingles later. There is a vaccine against chickenpox which is used routinely in some countries such as US but the UK public health programme limits to some sections such as non-immune health care workers although the vaccine can always be obtained privately.
Aciclovir is also available as a cream but this is only really suitable for small areas as in cold sore treatment around the mouth – more of this when there is space to write in more detail about cold sores and genital herpes in another issue!
Dr Ken Prudhoe, MCA Approved Doctor, can be contacted at Club de Mar Medical Centre, Palma de Mallorca.