Irritans

Irritans is the Latin present participle meaning "irritating" or "causing irritation." In modern scientific writing the term irritans is rarely used on its own; instead irritant serves as the English noun and adjective. The form irritans may still appear in taxonomic names or as a descriptor in Latin phrases within scientific literature.

An irritant is a substance or agent that provokes irritation of tissues on contact, most commonly skin, eyes, mucous membranes, or the respiratory tract. Effects depend on concentration, duration of exposure, and the particular tissue, and can range from mild redness to inflammation or chemical burns. Mechanistically, irritants cause direct cellular damage and elicit inflammation; they do not require prior sensitization.

Examples span chemical, physical, and environmental agents. Chemical irritants include acids, alkalis, solvents, detergents, and fumes; ocular irritants include ammonia and chlorine; respiratory irritants include smoke or dust. In everyday life irritants are found in cleaning products, cosmetics, industrial atmospheres, and some plant compounds. Reactions may manifest as irritant contact dermatitis, conjunctivitis, or bronchitis, depending on exposure route.

Regulatory and medical frameworks distinguish irritants from sensitizers (allergens). Irritants can trigger symptoms in anyone at sufficient exposure, though sensitivity varies. Assessment often involves irritation tests or observed clinical reactions, and avoidance or protective measures are standard management.

See also: irritant, contact dermatitis, ocular irritation, chemical irritation.