irritants

Irritants are substances that cause irritation of the skin, eyes, or mucous membranes through direct chemical or physical action. Irritation arises from tissue damage or localized inflammation that does not involve an immune sensitization process. The severity of the response depends on the concentration, duration of exposure, and the individual’s susceptibility.

Common sites of irritation include the skin (irritant contact dermatitis), the eyes (conjunctivitis and irritation), and the respiratory tract (irritant-induced coughing, inflammation, or pneumonitis). Examples of irritants include strong acids and alkalis, ammonia, chlorine, alcohols and other solvents, detergents, and certain dusts or fumes. The effects can be immediate or delayed and may be acute or chronic with repeated exposure.

A key distinction is that irritants are not the same as sensitizers. Sensitizers cause immune-mediated reactions (allergic contact dermatitis, occupational asthma) after an initial exposure, and reactions may worsen with subsequent exposures. In contrast, irritants can provoke reactions in a non-immune manner, often on first contact, though repeated exposure can intensify the response.

Diagnosis is based on history and clinical examination; patch testing is used to identify allergic sensitizers but not irritants. Management focuses on removing or reducing exposure and providing appropriate care for symptoms. Acute exposures may require irrigation, wound care, and, if necessary, topical corticosteroids or other anti-inflammatory measures.

Prevention emphasizes substitution with less irritating substances when possible, proper ventilation or containment, and the use of personal protective equipment. Occupational guidelines may establish exposure limits to reduce risk. See also irritant dermatitis, chemical burn, and sensitization.