You are never too old for allergies
If you've come through childhood managing to avoid the sniffles, sneezes and itches of allergies, you may not be out of the woods yet.
Many new allergies occur as adults, often in the 30s and 40s.
"There is not always an obvious reason as to why some people develop allergies in later life," says Lindsey McManus deputy chief executive of Allergy UK.
"We don't fully understand why allergies occur at different stages of our lives, particularly in those that develop an allergy later on. They may be triggered by illness or stress. Our immune systems could be overloaded and an allergy develops as a consequence" she says.
What is an allergy?
An allergy develops when your immune system thinks that a substance like pollen, dust or a certain food is harmful. It then leads to your immune system releasing chemicals, including histamine, which can lead to the symptoms of allergy that include rashes, itchy eyes, hives, streaming nose, sneezing, tingling mouth, swelling of airways and wheezing.
Allergic reactions can be anything from mild, to the incredibly serious anaphylaxis which can kill.
It may be an old allergy
Allergies in childhood sometimes disappear and then can return years later or manifest differently, for example affecting the airways, skin and gut.
Some people are genetically pre-disposed to allergies. For instance, if as a child you had eczema, you are more likely to develop allergies like asthma or hayfever in later life.
"A person who develops late onset hayfever would already have a genetic predisposition to allergy and for some reason the allergy operator gene gets switched on," says Beverley Adams-Groom chief palynologist at the National Pollen and Aerobiology Research unit at Worcester University.
Late onset reactions can be triggered if your immune system is reacting differently to an allergen as an adult than you did as a child.
Allergies don't happen when you first encounter an allergen. Your immune system has to become sensitised to it first before any reaction can happen.
Also, it may be the case that your immune system has become more reactive to the allergen, so symptoms that were once mild are now more severe.
"Repeated exposure to an allergen can lead to sensitisation which in turn can lead to allergic reactions," says Lindsey. "For example some bakers who've worked with flour for years develop an allergic reaction to it."
Other jobs can trigger allergic reactions. Working with certain chemicals and solvents for example, can cause contact sensitivities or allergies.
" Contact dermatitis can be triggered by substances or allergens in the workplace" says Lindsey. "If you are a hairdresser and are continually using certain chemicals you could go on to develop a sensitivity or an allergic reaction."
If you can pinpoint what's caused your allergy to develop, try to change that aspect of your job. Wear a mask if you are a baker, wear gloves when you are using chemicals for example, if you are a hairdresser.
Moving to a new area or a new house may cause late onset allergies to develop. Things like dust mites, mould or animal dander from the previous owners' pets can set them off.