Food challenges: Hospital

Hospital challenge is Indicated when the likelihood of a reaction being elicited is relatively higher or where a home challenge is not acceptable.

Hospital challenge may be for diagnostic reasons if there is clinical uncertainty or to demonstrate resolution of pre existing allergies and for research purposes. Occasionally children who would be considered certain to react during challenge on the basis of existing tests but who have never actually reacted, or, who have forgotten how they reacted may need to have a challenge to educate them about the clinical signs they should recognize. This is most common in adolescents.

Hospital oral food challenges need to be performed as a day case procedure. Access to full resuscitation equipment is essential. Staff conducting and supervising the challenge should be competent in doing so. The ability to recognise and treat allergic reactions is essential.

Practicalities

  • Compliance and co-operation from the child is vital. It is worth discussing with the parents before hand as otherwise it will end up a wasted trip for all involved. The most difficult age group is 4-6yrs.
  • Parents will bring the required food if the hospital cannot provide it, and they have no problem doing so.
  • A normal portion of food that is being challenged needs to be consumed over 5 or 6 doses in incremental 15-20 minute intervals. The last dose is always half the total dose so it’s as easy to work backwards if necessary.

Food: Peanut

Setting: Hospital / Paediatric Day Unit
Amount:

  • 8g of Regular salted Peanuts, but peanut butter is a safer option for younger children.
  • If using peanut butter a generous spread over a (sliced pan) slice of bread, if the child cannot tolerate bread, crackers or bread the child can tolerate can be used.

Method:

  • Start with a lip rub and work the dose up every 15-20 minutes for example , lip rub, ¼ peanut, ½ , 1, 2 ,4 etc. If using peanut butter on bread, divide into 5 doses the last dose being half the amount, work the doses out backwards if it’s easier.
  • Children must be observed for 2 hrs after completion of the last dose.

Tips:

  • The taste can be difficult to tolerate so peanuts can be crushed up and the doses can be mixed with yoghurt as an alternative, jam can be used over the peanut butter to help disguise the taste.

Outcome 1: If the oral food challenge is negative peanut must be introduced into the diet at least 2-3 times a week.

Outcome 2: If the oral food challenge is positive peanut must be strictly avoided, and arrange appropriate follow up.

Food: Baked Egg

Setting: Hospital / Paediatric Day Unit
Amount:

  • Give the following recipe to the parents (to be made the day before the food challenge when the child is not in the vicinity). 2 oz flour, 2oz sugar, 2 oz margarine, 2 eggs. Divide the mixture to make 4 fairy cakes and bring all 4 cakes to the challenge. If the child has an allergy to any of the other ingredients i.e. milk, wheat, they use their alternatives in the recipe.
  • 2 cakes which is equivalent to one egg needs to be eaten.
  • If younger children can’t manage the volume, completion at half the dose is acceptable.

Method:

  • Divide the cakes into 5 doses the last dose being half the amount, work the doses out, backwards if it’s easier.
  • Give the child incremental doses every 15-20 minutes.
  • Children must be observed for 2 hrs after completion of the last dose.

Outcome 1: If the oral food challenge is negative baked egg must be introduced into the diet at least 2-3 times a week.

Outcome 2: If the oral food challenge is positive baked egg must be strictly avoided, and arrange appropriate follow up.

Food: Straight Egg

Setting: Hospital/Paediatric Day Unit
Amount:

  • 1 whole scrambled egg or
  • Pasteurised whole egg powder can be used (available from www.myprotein.co.uk ). 30g is equal to one egg, ask the parents to bring yogurt or fruit puree that the child usually eats to mix it in with.

Method:

  • Divide the egg or egg powder into 5 doses the last dose being half the amount, work the doses out, backwards if it’s easier.
  • Give the child incremental doses every 15-20 minutes.
  • Children must be observed for 2 hrs after completion of the last dose.

Outcome 1: If the oral food challenge is negative straight egg must be introduced into the diet at least 2-3 times a week.

Outcome 2: If the oral food challenge is positive straight egg must be strictly avoided, and arrange appropriate follow up.

Straight Cow’s Milk

Setting: Hospital/Paediatric Day Unit
Amount:

  • For Children under 1 year use regular infant formula, starting with 1ml, 5ml, 10ml, 25,ml, 50ml.
  • For children over 1 year use full fat cow’s milk: disguise the taste using some of the child’s regular milk if needed.
  • For children over 5 yrs add an extra dose i.e. 1ml, 5ml, 10ml, 25,ml, 50ml, 100ml.
  • Marvel a dried milk product is useful to use if the child cannot tolerate the taste of full fat milk. It is also used when conducting double blind placebo controlled challenges, the protein content is the same as regular cow’s milk.
  • The same principals apply for a soya milk challenge.

Method

  • Give the child incremental doses every 15-20 minutes.
  • Children must be observed for 2 hrs after completion of the last dose

Outcome 1: If the oral food challenge is negative cow’s milk must be introduced into the diet at least 2-3 times a week.

Outcome 2: If the oral food challenge is positive cow’s milk must be strictly avoided, and arrange appropriate follow up.

Food: Baked cow’s milk

Setting : Home or hospital/paediatric day unit
Amount: 2 full buns (2.6 g of baked milk protein approx. per bun)
Parents should make the following at home in the absence of the child (and bring all with them if for a hospital challenge)

100 g (4 oz) butter, 100 g (4 oz) caster sugar, 2 eggs, beaten, 50 g (2 oz) self-raising flour, 56g Marvel (dried skim milk powder). If the child has an allergy to any of the other ingredients i.e. egg, wheat, they use their alternatives in the recipe.
Spread out 8 paper cases on baking sheets. Cream the butter and sugar together until pale and fluffy. Gradually beat in the egg, a little at a time, beating well after each addition. Fold in the flour & Marvel. Fill the paper cases half full. Bake at 175°C (350°F) mark 4 for 30 minutes.
Transfer to a wire rack to cool.

Amount: 4.6g baked milk protein per serving
Any brand of cheese pizza cooked at 425F/220C/Gas 7 for 13 minutes.

Method:

  • Choose a time and a day that suits the child and family.
  • Do not do on a day that the child is unwell or scheduled to take vigorous exercise later in the day.
  • Have oral antihistamines available.
  • Divide the cakes into 5 doses the last dose being half the amount, work the doses out, backwards if it’s easier.
  • Give the child incremental doses every 15-20 minutes.
  • Children must be observed for 2 hrs after completion of the last dose.

Stop at the first sign of a reaction: e.g. swollen lip, itching, redness, nettle sting type rash, vomiting, wheezing. Give antihistamines. If not improving, seek medical attention.

Outcome 1: If the oral food challenge is negative baked milk must be introduced into the diet at least 2-3 times a week.

Outcome 2: If the oral food challenge is positive baked milk must be strictly avoided, and arrange appropriate follow up as per the care pathway.

Food: Tree Nuts

Setting: Hospital/Paediatric Day Unit
Amount: 8g of the Tree nut being challenged
Method:

  • Start with a lip rub and work the dose up every 15-20 minutes for example , lip rub, ¼ tree nut, ½ , 1, 2 , etc.
  • Tree nuts can be crushed and added to some yoghurt as it is easier to eat. A mortar and pestle can be used to crush the nuts.
  • Give the child incremental doses every 15-20 minutes
  • Children must be observed for 2 hrs after completion of the last dose.

Tips for mixed nut challenge:

  • Mix 8g of each tree nut (crushed) with some yoghurt as it is easier to eat, there is no need to do a lip rub in this case as it is not practical.
  • Give the child incremental doses every 15-20 minutes.
  • Children must be observed for 2 hrs after completion of the last dose

Outcome 1: If the oral food challenge is negative the tree nut must be introduced into the diet at least 2-3 times a week.

Outcome 2: If the oral food challenge is positive to the mixed tree nut challenge the tree nuts must be strictly avoided, and individual challenges with the tree nuts will need to be performed.

Non food challenges: Antibiotics/ Drugs

The dose can be given in divided doses or as one total dose. The same principles apply as those for food challenges.