Contactants

Contactants are substances that can cause harm or irritation upon direct contact with the skin or other tissues. This type of interaction is often referred to as contact dermatitis, which can manifest in various forms, including irritant contact dermatitis and allergic contact dermatitis.

Irritant contact dermatitis is the more common form and occurs when a substance directly damages the skin's outer layer. This damage is caused by the chemical or physical properties of the contactant, such as strong acids, alkalis, solvents, or even prolonged exposure to water. The reaction is typically localized to the area of contact and its severity depends on the concentration and duration of exposure. Symptoms can include redness, itching, burning, and dryness.

Allergic contact dermatitis is an immune system response to a specific substance, known as an allergen. When the immune system becomes sensitized to an allergen, subsequent contact triggers an inflammatory reaction. Common allergens include poison ivy, nickel, fragrances, and certain preservatives. The reaction may appear as a rash, blisters, or hives, and can spread beyond the immediate area of contact. Diagnosis often involves patch testing to identify the specific allergen.

Prevention of contact dermatitis involves avoiding known irritants and allergens, wearing protective clothing when handling potentially harmful substances, and practicing good personal hygiene. Treatment focuses on removing the offending agent and managing symptoms with topical creams or oral medications.