Oral drug challenge: Not all drug reactions are true hypersensitivity reactions. An oral challenge may be to done to assess if a patient is truly allergic and must avoid the drug. The patient is administered small doses of the potential allergen, initially as a skin and epicutaneous test, and then incremental increases orally until the therapeutic dose is achieved. The patient is watched throughout the challenge for an immediate type reaction such as anaphylaxis. Depending on the drug, the patient may be instructed to take the drug for several days after the visit. Oral drug challenges can help to liberalize medication and treatment options and determine potential risk of anaphylaxis.
Oral food challenge: An oral food challenge may be employed as the final step in the diagnosis of food allergy. Scratch testing and occasionally blood testing are required prior to a food challenge, which involves incremental increases in exposure to a suspected food allergen. Between each consumption the patient is monitored for reaction. A food challenge can help to liberalize a patient’s diet.