Q: I'm going on holiday to Thailand and have been advised to take an antibiotic called doxycycline against malaria. I remember being prescribed the same drug when I had acne as a teenager. Is it the best one and does it really work?
A: You're right. It's the same antibiotic used in acne, but also helps to protect against malaria. None of the antimalarial drugs is perfect. Resistance to all of the drugs is becoming an increasingly complex problem and no drug regime is a substitute for measures to prevent getting bitten in the first place, eg chemically treated nets to sleep under and clothing that covers you from head to foot. Doxycycline can upset your tummy and in three out of a hundred users causes a rash in sunlight which can put a major dampner on your holiday. You can't use it if you're pregnant, but otherwise it's a good one to take. An alternative regime would be the drug combo of atovaquone and proguanil (Malorone) which works well and causes fewer side effects.
Q:I am plagued by cramps in my legs at night. They are ruining my sleep.What causes them and what on earth can I do?
A: Cramps are painful spasms in your leg muscles. They come on at night or sometimes after exercise, get worse as you get older, and have affected over two thirds of people over 50 at some time or another. No one knows what causes them, though they're worse in pregnancy, if you have poor circulation or severe salt depletion. Quinine tablets work on their own or in combination with the anti-asthma drug theophylline. Vitamin E supplements, painkillers and drugs used to treat epilepsy have been tested but don't seem to help. Knowing that your cramps don't indicate severe underlying disease may also help to give you peace of mind, if not a cramp-free night.
Where's my energy gone?
Q: I am a 16-year-old female and over the past year have been feeling constantly tired and lethargic. I don't understand why as I follow a healthy, varied diet, get plenty of sleep and do regular, albeit not huge amounts of exercise. I miss the energy I used to have - is this an inevitable part of growing up?
A: It's a common complaint, but not inevitable. Eating disorders, depression and a few physical complaints can cause excessive tiredness. Ask yourself honestly whether you're eating enough or whether you're becoming depressed and get help if you are. You could also ask your GP for a blood test to include a full blood count to check for anaemia (possible if you have heavy periods and don't eat much iron, which is found mainly in red meat), an underactive thyroid or glandular fever. If you don't have any other specific symptoms, it is unlikely that you will find one cause of your tiredness. Gradually increasing the amount of exercise you do may boost your energy levels.
Hair loss worries
Q: I am a woman of 61, still in full-time work as a university lecturer though retiring in the next year or two. For the past year I have been experiencing significantly increased hair loss from all over my scalp. In the past there have been short-lived episodes of this, generally associated (as far as I can recall) with periods of stress. Neither of my parents had this problem, so I am wondering what the cause might be if not genetic or hormonal. What can I do to help myself and what are the treatment options?
A: Hair loss can be due to diseases affecting the scalp (scarring alopecia) or occur in normal scalps (non scarring). The non-scarring type is far commoner and can include patchy hair loss or the more diffuse hair loss that you have. The usual culprit are the male sex hormone testosterone that both men and women have. Men get the characteristic receding hairline and bald crown whereas women get gradual hair loss across all the scalp. Minoxidil (Regaine) liquid applied to the scalp may help a bit. HRT may also be worth a try if you were considering it anyway, but comes with no guarantees. An underactive thyroid can make your hair thin, coarse and dry, can be detected by a blood test and treated with thyroid replacement. Iron deficiency can also make hair sparse while stress and certain drugs can make your hair fall out. Hair dyes that irritate the scalp a great deal may cause some patchy hair loss. You need a good and sympathetic hairdresser both to advise about mild hair products and disguise any hair thinning with a creative cut.
These answers are intended to be as accurate and full as possible, but should never be used as a substitute for visiting a doctor and seeking medical help. If you have a question for Dr Robinson, email firstname.lastname@example.org or write to her c/o The Health Editor, The Guardian, 119 Farringdon Road, London EC1R 3ER. She regrets that she cannot enter into personal correspondence.