Even if you pay a premium to stay in an expensive hotel, you run the risk of finding unwanted companions in your bed. A reader from London recently emailed me to say she had been very badly bitten by bed bugs at a four-star hotel in Iceland.

So how can you tell whether your hotel room has been infested? And if it is, what can you do about it?

Bed bugs are oval, brown and around 4mm to 5mm long – about the size of a ladybird. But because they are nocturnal, you can’t usually see them during the day. You need to check creases in mattresses, gaps under headboards, cracks in plaster or between timber floorboards, where they hide. Apart from the bug itself, telltale signs of infestation include dark pellets of faeces, yellowing cast-off skins and a distinctively sweet, sickly smell which you may be able identify when you enter, in much the same way that you can smell if a room is damp.

Bed bugs aren’t life-threatening but they feed on human blood during the night, consuming four times their body weight in under 15 minutes. Their saliva causes itchy, red spots that can be confused with mosquito bites. A key way to tell them apart is that bed-bug bites form a line, whereas mosquito bites are usually randomly spaced. Antiseptic soap, calamine lotion or anaesthetic creams can help soothe itchiness and avoid infection.

What to do if your room is infested

If you find any bed bugs, you should change hotels – not just rooms. Baths are bug-free zones, so put your luggage in the tub while you check your hotel room.

If you are bitten and think you may have brought bugs home, throw away your suitcase without bringing it indoors and wash your clothes at 60C or higher, or have them dry-cleaned.