All Things Allergy – Symptoms and Contributing Factors

Share Now:

An allergy can manifest itself in various ways and at any age. While most common in children, adults can develop allergies too.

Whether you’re a concerned parent or an individual wanting to expand your knowledge and understanding of these hypersensitivities you’ve come to the right place.

From common symptoms to look out for, to genetic and environmental factors, senior medical allergy consultant Dr José Costa gives an in-depth overview of all things allergy.

What is an allergy?

An allergy is a defensive reaction from our immune system to substances, aka allergens, we have come into contact with that the body does not recognise as safe.

Allergens can be found all around us, including certain foods, pet dander, pollen, house dust mites, and bee or wasp venom.

Chemicals and medications can also be allergens, with the most common ones being nickel, cobalt, and penicillin.

An allergic reaction can happen when a substance is either ingested, airborne (which can be either droplets or minuscule solids), injected, or through direct skin contact.

Not all allergens we come into contact with will cause our immune systems to react. Some allergens are quite harmless, and the level of severity will depend on each individual immune system.

Symptoms to look out for

Ingested symptoms

  • These may present in the form of itching, red skin or hives (starting around the mouth), sneezing, swelling, and vomiting.
  • In worst cases symptoms could include breathing problems and an altered conscious state – what we call anaphylaxis.


  • Runny, stuffed, or itchy nose; sneezing
  • Itchy or swollen eyes.
  • Headaches or a dull feeling in the forehead.
  • Itchy or sore throat, post-nasal drip, or cough.

Physical contact

  • Look out for local development of hives, redness, and swelling.


  • These are similar to symptoms of ingested allergens, with the onset being relatively fast; however, in some cases, symptoms can present a few weeks later.

Contributing factors & development

Are allergies genetic?

Many have pondered this question and while there have been no genetic links with food allergies that have been clinically proven to date – research is still ongoing in this area.

It is often thought that genes related to conditions such as asthma, allergic rhinitis, and eczema might be linked to a food allergy, but this is actually an indirect effect of other genes.

When pregnant and breastfeeding, women are encouraged to avoid certain foods. This decreases the baby’s exposure to allergens, with them potentially becoming less tolerant to those allergens and therefore more prone to the development of allergies.

Does it seem like there are more allergies than there were in the past?

That’s because there are! Allergies are increasing because our homes are cleaner. Hygiene is important, but like many things in life, it’s important to get a balance.

Germs are actually good for our immune systems; they challenge them and make them stronger to fight off serious infections.

Studies show that children living in the countryside have fewer serious allergies than those in the city because of their exposure to germs and dirt.

If you suspect that you might have an allergy or need further advice about managing medically diagnosed allergies, it is important to consult with your GP at the earliest opportunity.

Want more information about Dr Costa? Check out his Instagram, @childrensallergy, and visit his website.