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eMed previously Babylon Health

Allergy Symptoms and Testing

Edited by Dr Claudia Pastides, 17th April 2019

There are many different causes of an allergy and varying levels of allergic reaction. A lot of common conditions are actually caused by allergies, such as hay fever. Having an allergy can start to affect your life negatively without the correct treatment. The most common allergens (which cause allergic reactions) are pollen, food, dust, medication and chemicals in certain products.

Allergy symptoms

An allergic reaction can vary from mild to severe. Different allergens can also cause different reactions in the body, so you may not see the same symptoms if you have hay fever and then suffer an allergic reaction from hair dye. Here are some common symptoms:

  • Sneezing
  • Itchy, watery eyes
  • Breathing difficulties such as wheezing, breathlessness, chest tightness
  • Itchy rash, typically hives/nettle rash
  • Eczema and asthma symptoms
  • Anaphylaxis – a very severe allergic reaction which requires urgent medical treatment. Its main symptoms are: swelling of the lips, tongue and throat, breathing problems like wheeze and hoarseness and in severe cases collapse and loss of consciousness.

You may experience just one or a combination of symptoms. If you’re not sure if you have an allergy or can’t determine what you’re allergic to, speak to a GP to discuss your symptoms.

Allergy causes

The immune system responds to a harmless substance as though it is harmful, and we’re still not sure why, or what contributes to becoming prone to allergies. Allergies are very common in children, and they can sometimes disappear, but in many cases an allergy lasts a lifetime. Sometimes you may have symptoms of an allergy but are unable to identify what you’re allergic to. Here are some of the most common causes of allergies:

  • Grass and tree pollen
  • Dust and dust mites
  • Insect stings and bites
  • Food – nuts, shellfish, dairy products, fruit
  • Medication – antibiotics such as penicillin
  • Latex
  • Chemicals in hair dyes, body products and household cleaners
  • Animals, especially domestic pets such as cats and dogs

Allergy testing

This is commonly requested, but not always useful as tests do not always reveal a cause. Many people mistakenly believe there is a blood test they can have to check for any specific allergy.

It is more useful to prove a suspected allergy, rather than to screen randomly for any allergy. This is because virtually anything can potentially cause an allergic reaction. There are an infinite number of allergens - certainly too many to test for. Most allergy tests involve testing for a few common allergies.

There are 3 main ways to test for allergy: skin prick tests, blood tests and patch tests.

Treatment for ongoing allergies

The best treatment for an allergy is to avoid your allergen – but this isn’t always possible. If you suffer from hay fever, asthma or another allergy which impacts your life regularly, you should see a doctor to help you manage the problem. However, if you know you are allergic to certain foods or medication, then you should be able to ensure you don’t come into contact with them to avoid a reaction.

There are multiple ways to manage allergies, including medication to combat the symptoms. Antihistamines can be used before and during exposure to an allergen, while decongestants and steroids can offer short term relief from the symptoms of an allergy. If you don’t know what is causing the allergic reaction, a doctor can use a symptom tracker and recommend ways to help you deal with the symptoms.

Similar Conditions

The information provided is for educational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Seek the advice of a doctor with any questions you may have regarding a medical condition. Never delay seeking or disregard professional medical advice because of something you have read here.