There are two common causes of this - psoriasis, and fungal infection of the nails. Psoriasis is usually thought of as a skin condition, but it can also affect the nails, causing them to become deformed, with white, tiny pits on the surface. It is possible to have very minor skin psoriasis and quite bad nail psoriasis. Fungal infections of the nails are more common on the toenails. They are caused by a variety of organisms and the only way to be sure of the cause is for your doctor to send a sample of the nail off to the microbiology laboratory.
Psoriasis of the nails is difficult to treat, but the same creams that are used on skin psoriasis can be used around the nails. Fungal infections of the nails can be treated with anti-fungal tablets - terfenadine is the most effective. But you have to take the tablets for many months and there are potentially serious side effects. I often think the treatment for fungal nail infections is worse than the disease, and I discourage patients from using these tablets unless the infection is severe. Another unusual cause of ugly nails is yellow nail syndrome, which makes the nails thick and yellow. Vitamin E seems to help this.
I AM going to be travelling for a year in South America and I would like to find out my blood group, but my GP refuses to test me on the grounds that it is a waste of time. How can I persuade him to change his mind?
Many hospital laboratories now refuse blood-grouping requests for travellers because they believe it is of no practical use. Any medical facility, no matter how remote, that is capable of giving a blood transfusion, will also be able to check blood groups and, more importantly, test your blood against the blood of a potential donor to make sure there is not a mismatch. Even if you did know your own blood group, you would have no way of knowing the blood group of a potential donor, unless you were travelling with a companion whose blood group was also known to be compatible with your own. One simple and altruistic way of discovering your blood group is by becoming a blood donor.
To find out the name of your nearest donor centre, ring 0345 711711. If you are travelling to remote areas with poor medical facilities there is a risk of hepatitis B or HIV infection from unsterile needles. Take a pack of sterile needles and syringes. These can be purchased from travel medical centres.
I FIND injections and blood tests terribly painful. I have heard of a cream that numbs the skin. Does it work?
There are two creams, Ametop and Emla, that anaesthetise the skin before an injection or blood test. Both are local anaesthetics that have to be applied before the injection and covered with a special plaster. They are routinely used in children's wards, but there is no reason why an adult could not use them. Ametop is available from chemists without a prescription, but Emla requires a doctor's prescription.
Send questions to A Question of Health, `The Independent', 1 Canada Square, Canary Wharf, London E14 5DL; fax 0171-293 2182; or e-mail to email@example.com. Dr Kavalier cannot respond personally to questions