After repeated exposure, _____ will cause an allergic reaction?

After repeated exposure, _____ will cause an allergic reaction?

• A. Carcinogens.
• B. Irritants.
• C. Convulsants.
• D. Sensitizers/allergens.

Answer: (D)

Allergic reactions come from the immune system becoming sensitized to a substance after prior exposure. A sensitizer (an allergen) triggers an immune response, and with subsequent exposures the body reacts more strongly, producing symptoms such as itching, hives, swelling, or even anaphylaxis. This happens because the immune system has already produced specific antibodies (often IgE) to the substance, so re-exposure causes rapid release of histamines and other mediators from mast cells. The other effects listed are different hazard types: carcinogens increase cancer risk with exposure; irritants cause tissue irritation but don’t rely on a sensitization process; convulsants affect the nervous system and can cause seizures, not allergic reactions.

Allergic reactions come from the immune system becoming sensitized to a substance after prior exposure. A sensitizer (an allergen) triggers an immune response, and with subsequent exposures the body reacts more strongly, producing symptoms such as itching, hives, swelling, or even anaphylaxis. This happens because the immune system has already produced specific antibodies (often IgE) to the substance, so re-exposure causes rapid release of histamines and other mediators from mast cells.

The other effects listed are different hazard types: carcinogens increase cancer risk with exposure; irritants cause tissue irritation but don’t rely on a sensitization process; convulsants affect the nervous system and can cause seizures, not allergic reactions.