I seem to be affected by dandruff during the winter months, but it usually gets a lot better in the summer. I use an anti-dandruff shampoo throughout the year, but is there a reason for this improvement?

Certain natural yeasts that are produced by your body can cause dandruff to occur. The condition may develop if your body is sensitive to the yeast.

If this is the case, you may find that your dandruff improves during warmer months, and gets worse during colder months. This is because the UVA light from the sun counteracts the yeast.

Unfortunately, there is not much that you can do to prevent dandruff occurring. However, using an anti-dandruff, or anti-fungal, shampoo, once a week (or as prescribed on the bottle) may help to prevent the onset of dandruff.

You should brush your hair daily, and wash it at least three times a week. After washing your hair, make sure that you rinse it thoroughly in order to get all of the shampoo out. Avoid using chemicals on your scalp, such as those used in hair colouring.

See your GP if you concerned about the location, amount, and size of any flakes of dandruff that you have.

My four-year-old son is getting surgery soon to correct an eye squint. I'm worried about the procedure – what are the risks involved?

Surgery to correct a squint involves moving the muscles attached to the outside of the eye to a new position. As corrective squint surgery usually takes less than an hour to perform, the procedure is often carried out as a day case, so your child will probably be able to go home the same day. The operation is usually carried out under general anaesthetic, which means that your child will be asleep throughout the procedure.

You may be able to accompany your child to the operating theatre and stay with them until they have been given the anaesthetic. A nurse will be with your child throughout the procedure.

During the operation, your child’s eye will be kept open using an instrument called a lid speculum. The ophthalmologist will detach one part of the muscle that is connected to your child’s eye and will either move it backwards to weaken the pulling effect or shorten it to increase the pulling effect. Once the correction has been made, the muscles will be sewn back into place using dissolvable stitches.

There are risks associated with any kind of surgery. Ask your son's ophthalmologist to discuss the possible risks with you before the operation to put your mind at ease.

What is pertussis?

Whooping cough (pertussis) is a highly contagious bacterial infection of the lungs and airways.

The condition usually begins with a persistent dry and irritating cough that progresses to intense bouts of coughing. The gasping for breath after one of these coughing bouts causes a distinctive "whooping" noise, which is how the condition gets its name.

Other symptoms include a runny nose, raised temperature and vomiting after coughing.

The coughing can last for around three months (another name for whooping cough is the "hundred day cough").

See your GP as soon as possible if you think you or your child may have whooping cough.

Your GP can usually diagnose the condition by asking about your symptoms and listening to the cough (the whooping cough is very distinctive).

Whooping cough can also be confirmed with:

• a blood test – to test for antibodies to Bordetella pertussis bacteria

• a sample of mucus taken with a swab – to test for Bordetella pertussis bacteria

Whooping cough can be severe in young babies and, in some cases, they may need to be diagnosed and given very prompt treatment. In the UK, whooping cough is now rare due to children and pregnant women being vaccinated against it.