My 14-year-old son is in remission with acute lymphoblastic leukaemia and has a Hickman line in situ for his maintenance treatment. We are going to Disneyland Paris in a few weeks (by air). Should we tell the airline, and are there any possible problems?

Dr Jules Eden replies: There is no real need to tell them. A Hickman line is an intravenous line placed into one of the veins of the neck and going down towards the heart. This is done so that shots of chemotherapy can be given regularly without needing to place a line in the vein each time. It does not contain any air because after each dose it should be flushed through with normal saline/heparin mix to stop it from clotting up. So there are no worries regarding air expansion on take off. The only thing to watch for is on descent. When he has to equalise to pop his ears, this can raise the pressure in the thorax and there may be a bit of flush back down the line. Make sure that the cap on the line is tightly fitted in order to stop blood from oozing out.

I have a nut allergy and will be travelling to India (Goa) in a couple of weeks. I would like to take an adrenalin pen with me but I am not currently registered with a GP.

If your allergy is such that you are in danger of a severe allergic reaction, then it is a good idea to take an adrenalin pen. To get hold of one, you need a prescription from a doctor. If you cannot be registered with an NHS GP, then you could go private. This may cost £60 just for the consultation plus the price of the pen. Alternatively, you can go into any GP as a temporary patient, wait a long time, and plead your case.

If you have any questions you want to ask Dr Jules Eden, email travel.doctor@theguardian.com, or write to The Flying Doctor, The Guardian, 119 Farringdon Road, London EC1R 3ER.