don't make a rash judgement; finger on the pulse

What comes first, chicken pox or shingles? It's something I am often asked. And why does the baby of the family always come out in an ominous rash just before a christening or a silver wedding anniversary, when grannies and aunties are just about to descend. What is it? Is it contagious? Will Auntie Mabel get it? Should she stay away? And, most important of all, should they cancel the whole proceedings?

Chicken pox and shingles are the same virus - Herpes Zoster. Chicken pox starts off as a red rash and dries up after about five days. When the spots are crusty it's no longer infectious. Most people don't feel too unwell and they usually forget they ever had it. There always seems to be a debate over who's had what in every family - was it John or Jane who had the chicken pox or the measles? I certainly remember when my kids had chicken pox, because they had it one after the other. I saw the Postman Pat video a thousand times and I bought shares in calamine lotion.

Once you have had chicken pox, the virus goes to sleep along one of the nerves and may remain dormant. If your immune system becomes suppressed, for a variety of reasons, then the virus can be reactivated. When this happens it is called shingles.

The elderly are more susceptible to shingles, but young people also get it occasionally. The first sign of trouble is a burning or tingling sensation, followed by a rash and, possibly, some pain. Some people may be left with chronic pain as a consequence of shingles, but this can be prevented if the sufferer is treated early on with one of the modern antiviral agents.

But, remember, you can't get shingles unless you have had chicken pox. However, if you have got shingles, you can give other people chicken pox. Simple isn't it? You can't "catch" shingles, it's inside you already. The baby with chicken pox can't give Aunt Mabel shingles. But if Aunt Mabel has never had chicken pox, the baby may give her chicken pox. So, cancel the party if Aunt Mabel hasn't had chicken pox - or send the baby away.

Rashes of any sort can cause anxiety. In fact, many parents immediately presume that it means one thing - meningitis. Of course, this fear heightens when there has been a recent outbreak of the disease.

This was the case when a mother rang me in desperation one evening. Her six-year-old daughter had gone to bed well, but, at around 11pm, she started crying. The mother went to her daughter's room, turned on the light, and, not surprisingly, the child retreated under the covers. Mum's first thought was photophobia - the light was bothering her - and then she saw that her daughter was covered from head to toe in a rash.

The mother ran to the phone and called me. As rash and photophobia are two signs of meningitis, I jumped in the car and drove round. When I got there, I found a happy but itchy child playing with her doll. The only thing I could see that could have caused the rash was a recent arrival - a kitten, found asleep in the young girl's bed. I prescribed some antihistamines and reassured a very relieved mother.

Of course, awareness is important, but fear can sometimes prevent people looking and seeing what is really going on. I would rather check first and reassure afterwards. Always, I think, the best bet in childcare.