Symptoms of an allergic reaction
Allergic reactions usually happen quickly within a few minutes of exposure to an allergen.
They can cause:
- a runny or blocked nose
- red, itchy, watery eyes
- wheezing and coughing
- a red, itchy rash
- worsening of asthma or eczema symptoms
Most allergic reactions are mild, but occasionally a severe reaction called anaphylaxis or anaphylactic shock can occur.
This is a medical emergency and needs urgent treatment.
How to manage an allergy
In many cases, the most effective way of managing an allergy is to avoid the allergen that causes the reaction whenever possible.
For example, if you have a food allergy, you should check a food's ingredients list for allergens before eating it.
There are also several medicines available to help control symptoms of allergic reactions, including:
- antihistamines – these can be taken when you notice the symptoms of a reaction, or before being exposed to an allergen, to stop a reaction occurring
- decongestants – tablets, capsules, nasal sprays or liquids that can be used as a short-term treatment for a blocked nose
- lotions and creams, such as moisturising creams (emollients) – these can reduce skin redness and itchiness
- steroid medicines – sprays, drops, creams, inhalers and tablets that can help reduce redness and swelling caused by an allergic reaction
For some people with very severe allergies, a treatment called immunotherapy may be recommended.
This involves being exposed to the allergen in a controlled way over a number of years so your body gets used to it and does not react to it so severely.
What causes allergies?
Allergies occur when the body's immune system reacts to a particular substance as though it's harmful.
It's not clear why this happens, but most people affected have a family history of allergies or have closely related conditions, such as asthma or eczema.
The number of people with allergies is increasing every year.
The reasons for this are not understood, but 1 of the main theories is it's the result of living in a cleaner, germ-free environment, which reduces the number of germs our immune system has to deal with.
It's thought this may cause it to overreact when it comes into contact with harmless substances.
Allergy symptoms include sneezing, wheezing and itchy eyes. A life-threatening allergic reaction can also cause swelling and breathing difficulties.
If you have an allergy, try to avoid the thing you're allergic to if you can. Medicines like antihistamines can help ease symptoms if you need them.
Allergies are caused by your immune system mistaking a harmless substance for something harmful. Common triggers include pollen, food and animals.
Avoiding exposure to allergens
The best way to keep your symptoms under control is often to avoid the things you're allergic to, although this is not always practical.
For example, you may be able to help manage:
- food allergies by being careful about what you eat
- animal allergies by keeping pets outside as much as possible and washing them regularly
- mould allergies by keeping your home dry and well-ventilated, and dealing with any damp and condensation
- hay fever by staying indoors and avoiding grassy areas when the pollen count is high
- dust mite allergies by using allergy-proof duvets and pillows, and fitting wooden floors rather than carpets
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