What causes allergies to medications
Your immune system helps protect you from disease. It’s designed to fight foreign invaders such as viruses, bacteria, parasites, and other dangerous substances.
With a drug allergy, your immune system mistakes a drug that enters your body for one of these invaders. In response to what it thinks is a threat, your immune system begins to make antibodies. These are special proteins that are programmed to attack the invader. In this case, they attack the drug.
This immune response leads to increased inflammation, which can cause symptoms such as rash, fever, or trouble breathing.
The immune response might happen the first time you take the drug, or it may not be until after you’ve taken it numerous times with no problem.
What causes allergies?
Allergies occur when the body’s immune system reacts to a specific substance as though it’s harmful.
It’s not clear why this happens, but most people affected own a family history of allergies or own 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.
Substances that cause allergic reactions are called allergens.
The more common allergens include:
- medicines – including ibuprofen, aspirin and certain antibiotics
- latex – used to make some gloves and condoms
- insect bites and stings
- mould – these can release little particles into the air that you can breathe in
- dust mites
- food – particularly nuts, fruit, shellfish, eggs and cows’ milk
- grass and tree pollen – an allergy to these is known as hay fever (allergic rhinitis)
- animal dander, tiny flakes of skin or hair
- household chemicals – including those in detergents and hair dyes
Most of these allergens are generally harmless to people who are not allergic to them.
Symptoms of an allergic reaction
Allergic reactions generally happen quickly within a few minutes of exposure to an allergen.
They can cause:
- wheezing and coughing
- red, itchy, watery eyes
- a red, itchy rash
- a runny or blocked nose
- worsening of asthma or eczema symptoms
Most allergic reactions are mild, but occasionally a severe reaction called anaphylaxis or anaphylactic shock can happen.
This is a medical emergency and needs urgent treatment.
Is it an allergy, sensitivity or intolerance?
The exaggeration of the normal effects of a substance. For example, the caffeine in a cup of coffee may cause extreme symptoms, such as palpitations and trembling.
A reaction produced by the body’s immune system when exposed to a normally harmless substance.
Where a substance causes unpleasant symptoms, such as diarrhoea, but does not involve the immune system.
People with an intolerance to certain foods can typically eat a little quantity without having any problems.
Sheet final reviewed: 22 November 2018
Next review due: 22 November 2021
A drug allergy is an allergic reaction to a medication.
With an allergic reaction, your immune system, which fights infection and disease, reacts to the drug.
This reaction can cause symptoms such as rash, fever, and trouble breathing.
True drug allergy is not common. Less than 5 to 10 percent of negative drug reactions are caused by genuine drug allergy.
The relax are side effects of the drug. Every the same, it’s significant to know if you own a drug allergy and what to do about it.
Getting assist for allergies
See a GP if you ponder you or your kid might own had an allergic reaction to something.
The symptoms of an allergic reaction can also be caused by other conditions.
A GP can assist determine whether it’s likely you own an allergy.
If they ponder you might own a mild allergy, they can offer advice and treatment to assist manage the condition.
If your allergy is particularly severe or it’s not clear what you’re allergic to, they may refer you to an allergy specialist for testing and advice about treatment.
Find out more about allergy testing
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 own 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:
- lotions and creams, such as moisturising creams (emollients) – these can reduce skin redness and itchiness
- decongestants – tablets, capsules, nasal sprays or liquids that can be used as a short-term treatment for a blocked nose
- 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
- steroid medicines – sprays, drops, creams, inhalers and tablets that can assist reduce redness and swelling caused by an allergic reaction
For some people with extremely 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.