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Treatment - Food Allergy

There are 2 main types of medicine that can relieve the symptoms of an allergic reaction to foods:

  • antihistamines – used to treat mild to moderate allergic reaction
  • adrenaline – used to treat severe allergic reactions (anaphylaxis)


Antihistamines block the effects of histamine, which causes most allergic reaction symptoms.

Many antihistamines are available from your pharmacist without a prescription. Non-drowsy antihistamines are usually the best option.


Avoid drinking alcohol after taking an antihistamine. They can make you feel drowsy and affect your ability to drive.

For children

Some antihistamines are not suitable for children under 2. Ask your GP which ones are suitable for a younger child.


Adrenaline narrows the blood vessels to counteract the effects of low blood pressure. It opens up the airways to help ease breathing difficulties.

You'll get an auto-injector of adrenaline to use in emergencies. This is if you or your child is at risk or had a previous episode of anaphylaxis.

Read the manufacturer's instructions that come with the auto-injector carefully. Train your child how to use it when they're old enough.

Emergency action required: Call 112 or 999 and ask for an ambulance if:

  • you suspect that somebody is experiencing a severe allergic reaction

Tell the operator that you think the person has anaphylaxis.

Using an auto-injector

Older children and adults will probably have been trained to inject themselves. You may need to inject younger children or older children and adults who are too sick to inject themselves.

There are different types of auto-injectors. They all work in much the same way.

If anaphylaxis is suspected, you should:

  • remove the safety cap from the injector
  • press firmly against the thigh, holding it at a right angle, without using the thumb at the end.

A 'click' indicates the auto-injector has been activated. Hold it in place for 10 seconds. Make sure you're familiar with the device and know the correct end to place against the thigh.

The injections can be given through clothing. This will send a needle into your thigh and deliver a dose of adrenaline.

If the person is unconscious, check their airways are open and clear, and check their breathing. Then put them in the recovery position. Putting someone who is unconscious in the recovery position ensures they do not choke if they vomit.

Place the person on their side. Make sure they're supported by one leg and one arm. Open the airway by tilting the head and lifting the chin.

If the person's breathing or heart stops, cardiopulmonary resuscitation (CPR) should be performed.

Owning an auto-injector

Carry the auto-injector at all times. Encourage your child to do so if they're old enough. You may be prescribed 2 injectors. You may also get an emergency card or bracelet with full details of your child's allergy and the contact details of their GP. This to to alert others. They should wear this at all times.

Extreme temperatures can make adrenaline less effective. Do not leave an auto-injector in places like your fridge or the glove compartment of your car.

Check the expiry date often. An out-of-date injector will only offer some protection.

The manufacturers offer a reminder service, where you can be contacted near the date of expiry. Check the information leaflet that comes with the medicine for more information.

If your child has an auto-injector, they'll need to change over to an adult dose once they reach a weight of 30 kilos (4.7 stone). This could be anywhere between 5 and 11 years.

Do not delay injecting if you think you or your child may be experiencing the start of anaphylaxis, even if the initial symptoms are mild. It's better to use adrenaline early and find out it was a false alarm than delay treatment.

Content supplied by the NHS and adapted for Ireland by the HSE

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This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.

Page last reviewed: 13 March 2021
Next review due: 13 March 2024