Challenge Testing ( Drug challenge & Inhalation challenge)

Drug challenge

Skin testing can only be used to diagnose allergy to a few drugs such as penicillin and insulin. Drug challenge, where increasing amounts of a drug is given orally, subcutaneously or intravenously, is sometimes used to confirm or exclude drug allergy.

Allergy to food additives, which are chemicals and therefore behave more like drug allergy, also requires oral challenge for diagnosis.

Inhalation challenge

The defining characteristic of asthma is reversible lower airway obstruction. As asthma symptoms are often intermittent unless triggered by external factors, diagnosis can be difficult.

Drugs such as methacholine or histamine can trigger airway narrowing in asthmatics, and are used in inhalation challenge to diagnose asthma. Other specific asthma triggers such as aspirin and allergen can also be used.

Reference information: www.allergy.hk/

The information aims to provide educational purpose only. Anyone reading it should consult physician before considering treatment and should not rely on the information above.