Allergies in adulthood: Is it possible to develop an allergy later in life?

Although allergies can be common amongst young children, many adults may be surprised by the onset of new symptoms triggered by an allergy later in life. We invited renowned consultant in respiratory medicine and allergy Dr Raghu Raju to share his expert insight on adult onset allergies and what triggers them. The leading specialist also reveals which are the most common allergies to come on in adulthood and discusses how allergies are passed down through families.

How and when do allergies occur?

Allergies are essentially an abnormal immune response to what might be a completely harmless substance, say for example a peanut or a grass pollen. Our immune systems can sometimes perceive these substances as being dangerous and start attacking them, mistakenly thinking they are a virus, for example. The collateral damage that occurs is basically an allergic reaction.

We don’t completely understand exactly why this happens or why a person may react to certain chemicals and not others. However, we do know that genes certainly have a part to play in allergies, as well as a person’s environment.

There are different types of allergies that can develop at different times in life. Allergies are very common in early childhood, including food allergies, eczema, and a degree of allergic wheeze, and asthma. In adults, hay fever, certain types of food allergies and asthma are relatively common.

Is it possible to develop an allergy later in life?

Yes, certain types of allergies are common in later life. In fact, there are certain types of food allergies, as well as other specific allergic conditions, such as asthma and hay fever which are extremely common in adults. In fact, a lot of the adult population suffering from hay fever find that it's a condition that affects their quality of life, and so they commonly seek out for solutions.

Specific food allergies can sometimes be found for the first time in adulthood and there are some types of allergies which are only common in adults.

What can trigger an allergy in an adult?

There are lots of factors which can “switch on” an allergy, which can often suddenly seem as though it has appeared from nowhere. Sometimes a change in a person's circumstances can trigger an allergy, for example, moving to a new location where there are different allergens in the environment. In addition, changes in diet, hormones, chemicals, or stress can sometimes bring an allergy on.

What are the most common adult onset allergies?

The most common adult onset allergy would be allergic rhinitis, also known as hay fever. Asthma is also common in adults, and certain types of food allergies are much more common in adults than in children. For example, shellfish allergies and certain types of types of tree nut allergies are more common in adults, as is a type of food allergy known as pollen food syndrome or oral allergy syndrome. There are also many other conditions which start in childhood and can continue into adulthood, meaning that treatment will still be required as the person ages.

Can childhood allergies recur in adulthood?

Yes, childhood allergies can recur in adulthood. Allergies tend to be caused by our immune cells recognising an allergen to be dangerous. Our immune cells have a very strong memory, and so once a person is sensitised to an allergen, they tend to be sensitised for life.

Sometimes, the person may develop a degree of tolerance because they are being exposed to the allergen in small doses. However, for a variety of reasons exposure may not occur for a period of time. This may happen for a number of reasons, for example, someone relocating to live in a different place and then coming back to their original environment or to another environment where the allergen is present, and as a result, the allergens can start causing more symptoms. This can be perceived as an allergy that didn't previously exist, or sometimes, it's simply an allergy that was not really causing many symptoms but now has started to cause more problems in adult life.

Are allergies passed down through families?

Allergies certainly have genetic predisposition, and we are well aware that they run in families. If a parent has an allergy condition, the child has a 50 per cent chance of developing some sort of allergy. If both parents have some type of allergy, the child has a 75 per cent chance of developing allergies.

This doesn’t mean, however, that parent and child will necessarily have the same allergies. For example, if the parent has a nut allergy, this doesn't mean that the child will have a nut allergy, but rather that they are at risk of developing some sort of allergy – perhaps hay fever, a milk allergy, or something else completely different. Therefore, although allergies do run in families, parents do not necessarily pass on the same allergies to their children.




If you are struggling with allergy symptoms and wish to schedule a consultation with Dr Raju, you can do so by visiting his Top Doctors profile today.