A Question Of Health

Do I really need my 'freckle' to be treated? And why do mosquitoes find me so tasty?

SPOT CHECK

SPOT CHECK

Q. I have a freckle/sun spot/age spot the size of a 5p coin on my cheek. It is flat, but my GP wants to blast it with the cryotherapy gun he uses to freeze warts. Is this the best treatment? After all, it's only a freckle.

A. Large, flat, brown areas on the skin of the face and hands are usually caused by sun damage over many years. These spots are often called age spots or liver spots, but the technical name is benign solar lentigines (singular, lentigo). If you remove these spots and look at them under a microscope, they simply contain an excess of pigment-producing skin cells. They are not malignant and do not usually become malignant. If and when they start to become scaly, they are known as solar keratoses. These are caused by further sun damage and do have the potential to become skin cancer. There is no medical need to treat a smooth, flat solar lentigo unless your doctor is concerned that it has features of skin cancer. If the colour of the spot is very irregular, or if it has an irregular border, if may be transforming into skin cancer. Itching, bleeding and crusting are other warning signs of skin cancer. If in doubt, an expert opinion from a dermatologist is the best course of action.

ONCE BITTEN

Q. My wife and I are going on safari to Africa, and I know that she will be left alone by the mosquitoes and I will be eaten alive. Why does this happen?

A. Mosquito bites are a global health problem. It is estimated that mosquitoes transmit disease to more than 700 million people every year - the death of one in every 17 people now alive will be caused by their bites and the infections they transmit. Mosquitoes carry malaria, yellow fever, dengue fever and some types of encephalitis. Malaria causes more than a million deaths a year, mostly in Africa.

Mosquitoes are attracted to the sight, smell and heat of human beings. They like the carbon dioxide we exhale, and are attracted to the lactic acid produced in our muscles. There are also many other chemical compounds in our breath and on our skin that attract mosquitoes. Some perfumes, soaps and hair products make it more likely that mosquitoes will find you. They prefer adults to children, big people to small, and men to women. People who sweat little are less attractive to mosquitoes than sweaty people.

The only reliable way to avoid getting bitten is to stay covered up, especially around dusk and at night. Insect repellents containing DEET are effective, but must be applied regularly as they wear off. Citronella oil is also effective, but doesn't last as long as DEET. When travelling to Africa, it is important to take antimalarial pills. You can get advice from the National Travel Health Network and Centre ( www.nathnac.org), or Health Protection Scotland ( www.fitfortravel.scot.nhs.uk).

Have your say: Readers write

SS from Surrey is convinced that there was a link between his gallstones and his muscle twitching:

In my forties, I had the same symptoms of widespread and very uncomfortable muscle twitching. My GP and a neurologist couldn't find a cause. However, after a few years, I suffered with acute attacks of pain that were found to be caused by gallstones. After an operation to remove my gall bladder, 10 years ago, the muscle twitching disappeared completely.

Send your questions and suggestions to A Question of Health, 'The Independent', 191 Marsh Wall, London E14 9RS; fax 020 - 7005 21 82; or e-mail health@independent.co.uk

Dr Kavalier regrets that he is unable to respond personally to questions