What kind of allergic reaction occurs from exposure to allergens or irritants?

Contact dermatitis is a specific type of allergic reaction that occurs when the skin comes into direct contact with allergens or irritants. This condition is characterized by inflammation and localized skin reactions, such as redness, swelling, and itching, which can arise from exposure to various substances like chemicals, fragrances, or metals.

Understanding contact dermatitis is important because it highlights the body's immune response to allergens, leading to a range of symptoms that can impact the skin's integrity and comfort. This reaction can occur soon after contact or may develop over time, illustrating the diversity in how individuals respond to allergens or irritants.

The other options represent different types of allergic reactions or skin conditions that don't involve direct skin contact, such as allergic rhinitis, which affects the nasal passages, hives, which are raised welts on the skin due to allergens in the bloodstream, and eczema, which is a chronic condition typically linked to an immune response but not directly from external contact in the same way.