What can cause dermatitis and what is it characterized by?

Dermatitis is a condition that can be caused by allergens or irritants, which trigger an inflammatory response in the skin. This inflammation typically results in symptoms such as redness, swelling, and discomfort. When the skin comes into contact with substances like soaps, detergents, or certain chemicals, or when it reacts to allergens like pollen or nickel, the immune system responds by sending inflammatory cells to the affected area. This response is the body's way of protecting itself from perceived threats, which is why inflammation is a key characteristic of dermatitis.

While other factors like infections, genetic predispositions, and autoimmune responses can certainly affect skin conditions, their characteristics and effects differ. For instance, infections might lead to redness and possibly pus accumulation, genetic factors can lead to conditions presenting as scaling, and autoimmune responses often cause itchiness without the typical inflammatory presentation associated with dermatitis. Therefore, among the options provided, the association of dermatitis with allergens or irritants resulting in inflammation is the most accurate characterization.