What is the main characteristic of dermatitis?

The main characteristic of dermatitis is the presence of inflammation, erythema, and pruritus. Dermatitis is essentially an inflammatory condition of the skin, which is defined by these signs. Inflammation results in swelling and redness (erythema), while pruritus refers to the itching sensation that often accompanies this condition, driving individuals to scratch the affected areas. This trio of symptoms can be indicative of various types of dermatitis, including atopic dermatitis, contact dermatitis, and seborrheic dermatitis, among others. The inflammation arises from the skin's immune response to irritants or allergens, which is fundamental to understanding how dermatitis presents clinically.