AAFM Boards Dermatology Practice Test

Contact dermatitis is the condition characterized by inflammation resulting from direct contact with a particular substance or chemical. This reaction can occur in response to irritants, such as soaps, detergents, or certain metals, or allergens, like nickel or poison ivy. When the skin comes into contact with these provoking agents, it triggers an inflammatory response, often resulting in redness, itching, and sometimes blistering.

The hallmark of contact dermatitis is that the inflammation is localized to the area of contact with the offending agent, distinguishing it from systemic or airborne allergic reactions. The diagnosis of contact dermatitis often involves identifying the specific substance that initiated the reaction, which can be confirmed with patch testing if necessary.

Other skin conditions, while they may involve inflammation, do not specifically arise from contact with substances or chemicals in the same direct manner. For example, allergic rhinitis is a reaction primarily affecting the nasal passages to airborne allergens and is not a dermal response. Psoriasis is an autoimmune condition that leads to rapid skin cell production and scaling rather than contact-related inflammation. Eczema, while it also features inflammation and can be triggered by irritants, often involves underlying atopic conditions and does not exclusively arise from direct contact with a substance like contact dermatitis does.