Practical details for food challenges
| (a) | Always conducted in hospital as a day case with easy access to resuscitation equipment and adrenaline—the one time you don’t have it available ... |
| (b) | No antihistamines for previous 24 hours |
| (c) | Can only test one allergen per day |
| (d) | An intravenous cannula must be inserted before starting |
| (e) | Usually 30 minute stages: food on skin, left for 1 minute, then wiped off, then touch corner of lip, then eat 0.5 gram (1 ml), then 5 grams (5 ml), then 15 grams (15 ml), then 50 grams (50 ml), all 30 minutes apart. After last stage wait 60 minutes, then home if no adverse response. Total time about 5 hours |
| (f) | Isolated nausea is rarely an allergy; more usually dislike of food + stress |
| (g) | If needing to challenge the following day with different food, then Heplok cannula and send them home with it in overnight (no baths/showers), to return in the morning |