Which statement about extrinsic asthma is true?

• A. It is non-allergic
• B. It is genetic in origin only
• C. It is allergic with elevated IgE
• D. It has no relation to allergens

Answer: (C)

Extrinsic asthma is an allergic, IgE-mediated form of asthma triggered by environmental allergens. In susceptible individuals, exposure to an allergen such as pollen, dust mites, or animal dander leads to allergen-specific IgE binding on mast cells. When the allergen cross-links these IgE molecules, mediators like histamine are released, causing bronchoconstriction and airway inflammation.

This is why the statement describing extrinsic asthma as allergic with elevated IgE is the best choice: the hallmark feature is the IgE-mediated allergic response to allergens. It is not non-allergic, and it is not solely genetic in origin; while genetics can influence risk, the defining aspect is the IgE-driven allergic reaction to specific triggers, showing a clear relation to allergens.