Why do I have allergies?

In simplest terms, an allergy is a condition caused by the immune system being too sensitive in response to something (an allergen) that in most people doesn’t cause problems. But let’s look at a more thorough answer to the question.

Like many other disorders of the weird and wonderful immune system, allergies are complex and at times confusing. If we think of the immune system as a task force, white blood cells are like patrolling policemen, circulating in our bloodstream every day of our living lives. Once a disease-causing agent (a pathogen) has been recognised, special mechanisms are activated, such as the release of antibodies and inflammatory substances like histamine.

In our task force analogy, antibodies are like fired bullets – they bind to the unique, identifying features on the surface of the invader. Histamine, on the other hand, makes blood vessels leakier, which while it may cause swelling, allows immune cells to reach tissues easily – like police cars speeding down the roads with sirens blaring as other cars make way.

A pathogen once fought is then remembered on an offender’s list of sorts, formed by memory cells and antibodies now present in greater numbers.

Now, just like in the world of law enforcement there are false accusations, the immune system can mistake a harmless substance for a threat and a response can be activated. From then on, the allergen remains on our offenders’ list, eliciting an allergic reaction each time it’s encountered.


Since there are so many different things to which someone could be allergic, there are also many symptoms that can arise. In general terms, symptoms will tend to be influenced by the area of the body at which contact with an allergen is made.

 Allergies to substances suspended in air will therefore cause:

  • a runny nose (allergic rhinitis),
  • sneezing,
  • coughing,
  • itchy, red eyes (allergic conjunctivitis),
  • shortness of breath,
  • wheezing.


Hayfever is a common example of allergies to an airborne allergen: pollen!

These are due to the allergen making contact with the mucosal surfaces of the nose, eyes and airways. On the other hand, someone with a food allergy could expect:

  • abdominal pain,
  • bloating,
  • nausea,
  • vomiting,
  • diarrhoea.

These happen as the food makes its way down the digestive system, causing inflammation. However non-gastrointestinal symptoms could also occur with food allergy such as itchiness and swelling of the skin.

Allergens which may spread via the bloodstream such as medications or insect bites can affect many sites at once, triggering just about any of the above symptoms. As you can see, allergic symptoms are many in number and overlap – it’s understandable why pinning down the exact culprit responsible for the condition can be tricky.



Skin rashes are also a common symptom of allergic reactions.

Although allergy is common, it shouldn’t be taken lightly. If you’ve experienced allergy yourself, you’ll know very well how the constant experience of symptoms can significantly affect the quality of life for so many.

Let’s have a look at what you can do:


Diagnosis and management

Anti-inflammatory medications such as antihistamines or glucocorticoids are the most common pharmacological interventions to help alleviate symptoms of allergy. However, as you can imagine, the best way to approach managing allergy is to avoid triggers.

To be able to do this you must be at least vaguely aware of what it is that you’re allergic to

We offer a wide range of allergy tests at London Doctors Clinic, the most accessible and affordable time with a GP London has to offer, to help you adapt your lifestyle and habits so that you can live life as free from allergic reactions as possible. During a consultation with one of our private doctors you will be able to discuss which allergy profile would suit you best. They include: 

  • General Allergy Profile (UK) - £232
  • Food & Inhalants - £667.20
  • Inhalants - £368
  • Food - £331.20
  • Shellfish - £298.40
  • Antibiotics - £212

If, for example, you suspect a certain cream, hygiene product or medication is responsible for the reaction, we can investigate the ingredient list for suspect agents, carrying out any appropriate blood tests to detect any allergic responses to any individual chemicals.

Finally, it’s important to have realistic expectations with regard to allergen-confirmation: there are millions of allergens out there, and sometimes it’s simply not worth the extensive money and time required to thoroughly investigate an obscure allergen. When these tricky cases crop up, it's often best to simply treat symptoms, while gradually narrowing down allergen options. It’s often the case that with time, through everyday observations (such as diary of potential-allergen exposures), the cause of the reactions will eventually become apparent.

So book in for a GP today for a 15-minute consultation, costing just from £89, to start your journey into allergy investigation and treatment with one of our experienced GP's. From here, should our investigations prove inconclusive, or problems continue, we can provide a private specialist referral to an Allergy Clinic.

By Dawid Mobolaji Akala