Q. I’ve come back from holiday wheezing and with a red rash - please help?

A. You may have had an allergic reaction to something your body isn’t used to. Allergies occur when the body's immune system reacts to a particular substance as though it's harmful. If you have been somewhere you haven’t been before its likely you’ve come into contact with some plant, pollen, food or something else you may not have encountered before.

It's not clear why this happens, but most people affected have a family history of allergies or have closely related conditions, such as asthma or eczema.

The number of people with allergies is increasing every year. The reasons for this aren't understood, but one of the main theories is it's the result of living in a cleaner, germ-free environment, which reduces the number of germs our immune system has to deal with.

It's thought this may cause it to overreact when it comes into contact with harmless substances.

There are several medications available to help control symptoms of allergic reactions, including:

• antihistamines – these can be taken when you notice the symptoms of a reaction, or before being exposed to an allergen, to stop a reaction occurring

• decongestants – tablets, capsules, nasal sprays or liquids that can be used as a short-term treatment for a blocked nose

• lotions and creams, such as moisturising creams (emollients) – these can reduce skin redness and itchiness

Seek help your local pharmacist for some suggestions about what may work best.