Dermatology Made Easy is based on the most popular topics from DermNet NZ's vast array of material. The book combines the essential focus of the ‘Made Easy’ book series with the authority and knowledge base of DermNet NZ's unparalleled resources.
Author: Vanessa Ngan, Staff Writer, 2003.
Irritant contact dermatitis is a form of contact dermatitis, in which the skin is injured by friction, environmental factors such as cold, over-exposure to water, or chemicals such as acids, alkalis, detergents and solvents.
Irritant contact dermatitis occurs when chemicals or physical agents damage the surface of the skin faster than the skin is able to repair the damage. Irritants remove oils and moisture (natural moisturising factor) from its outer layer, allowing chemical irritants to penetrate more deeply and cause further damage by triggering inflammation.
The severity of the dermatitis is highly variable and depends on many factors including:
Irritants include such everyday things as water, detergents, solvents, acids, alkalis, adhesives, metalworking fluids and friction. Often several of these act together to injure the skin.
Irritant contact dermatitis may affect anyone, given sufficient exposure to irritants, but those with atopic dermatitis are particularly susceptible. 80% of cases of occupational hand dermatitis are due to irritants, most often affecting cleaners, hairdressers and food handlers.
Irritant contact dermatitis can appear similar to other forms of dermatitis, particularly:
Irritant contact dermatitis is usually confined to the site of contact with the irritant, at least at first. If the dermatitis is prolonged or severe it may spread later to previously unaffected areas but it is less likely to do this than allergic contact dermatitis.
The dermatitis often appears as a well demarcated red patch with a glazed surface, but there may be swelling, blistering and scaling of the damaged area. This may be indistinguishable from other types of dermatitis. It can be very itchy.
Contact irritant dermatitis can appear differently according to the conditions of exposure.
Some typical examples of irritant contact dermatitis include:
In time, the skin may develop some tolerance to mild irritants.
Sometimes it is easy to recognise irritant contact dermatitis and no specific tests are necessary. The rash usually heals once the irritant is removed and, if necessary, special treatment is applied. Whilst there are some tests that can provide an indication of the irritant potential of substances, there are no specific tests that can reliably show what the effect of an irritant will be in each individual case. Irritant dermatitis in any case is usually the result of the cumulative effect of multiple irritants.
Patch tests are used to confirm allergic contact dermatitis and identify the allergen(s). They do not exclude irritant contact dermatitis as the two may coexist.
It is important to recognise how you are in contact with the responsible substance(s) so that, where possible, you can avoid it (them) or at least reduce exposure. Wear appropriate gloves to protect against irritants in your home and work environment.
Irritant contact dermatitis is usually treated with the following:
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