What is an Irritant?

Niki Foster
Niki Foster

Red peppers contain capsaicin, an irritant.
Red peppers contain capsaicin, an irritant.

In biology, an irritant is anything that causes irritation such as inflammation or pain. This may be chemical in nature, but it can also be mechanical, thermal, or radiative. Chemicals like the capsaicin in hot peppers, rough fabrics, friction, heat or coldness, and ultraviolet (UV) radiation are all examples of irritants. Irritants commonly affect the skin, eyes, or mucous membranes.

With contact dermatitis, many objects or materials can be irritants.
With contact dermatitis, many objects or materials can be irritants.

The Occupational Health and Safety Administration (OSHA) defines an irritant as having a temporary and local effect. Contact with irritants can sometimes be avoided by wearing protective gear such as goggles or gloves, and the first line of treatment against irritants is typically flushing the affected area with water. If irritation persists, a doctor should be consulted. Though irritation is a temporary problem, some irritants can cause more long-term damage.

Contact with an irritant may cause itching, swelling and redness.
Contact with an irritant may cause itching, swelling and redness.

Irritants are not the same as allergens, though the two may overlap. Allergens cause an immune response, while irritants cause irritation through abrasion or by removing moisture from the affected area. The effects of irritants are limited, at least initially, to the area in direct contact with them, while an allergen can have more widespread or systemic effects. Finally, a certain amount of an irritant is required to have an effect, while allergens can typically cause a reaction in much smaller amounts.

Contact with irritants may cause the skin rash eczema.
Contact with irritants may cause the skin rash eczema.

One possible effect of contact with irritants is a condition such as eczema or irritant contact dermatitis (ICD), which affects the skin. Symptoms can include redness, rash, blisters, itching, swelling, dryness, and scaling. Many different factors contribute to the severity and duration of irritant contact eczema. These include the duration and frequency of contact with the irritant, the irritant's strength and amount, the sensitivity of the sufferer's skin, and environmental factors.

Many people develop ICD in the winter due to cold, dry air.
Many people develop ICD in the winter due to cold, dry air.

ICD can affect anyone, though those with atopic dermatitis and those who frequently handle irritants as part of their job are most susceptible. Young children can develop ICD around the mouth from dribbling or licking their lips frequently. Also, many people develop the condition in the winter as a result of cold, dry air.

Irritants may lead to the development of allergies.
Irritants may lead to the development of allergies.

When allergy is ruled out, ICD can be treated with compresses, emollient creams, and sometimes topical steroids or antibiotics for secondary infections. The patient should avoid contact with the irritant whenever possible, and should keep the affected area clean and moisturized. The skin can develop tolerance to some irritants over time.

In most cases, hives are an acute condition triggered by exposure to soap, detergent, bubble bath or another irritant.
In most cases, hives are an acute condition triggered by exposure to soap, detergent, bubble bath or another irritant.
Contact with irritants may result in itchiness.
Contact with irritants may result in itchiness.
An irritant may affect the eyes.
An irritant may affect the eyes.
Niki Foster
Niki Foster

In addition to her role as a wiseGEEK editor, Niki enjoys educating herself about interesting and unusual topics in order to get ideas for her own articles. She is a graduate of UCLA, where she majored in Linguistics and Anthropology.

You might also Like

Readers Also Love

Discuss this Article

Post your comments
Login:
Forgot password?
Register: